Claves empleadas
XXXXXX Separa fuentes
Source: Marca el origen de un fragmento
Yellow highlighting Marca los fragmentos literales. Ejemplo:
They absorb nutrients through the cell wall or produce their own by photosynthesis.
Blue highlighting Marca los fragmentos adaptados. Ejemplo:
The most common system in use today is the Five Kingdoms system of classification. In this system all
organisms are divided into five kingdoms: Monera (Prokaryota), Protista, Fungi, Plantae, and Animalia.
→The five kingdom system is the most common system of classification in use. In this system
all organisms are divided into five kingdoms:
1. Monera
2. Protista
3. Fungi
4. Plantae
5. Animalia
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Source: Education Oasis 2010
http://www.educationoasis.com/curriculum/Science/pdf/SC_fivekingdoms.pdf 18-12-2010
Five Kingdom Classification System
Once upon a time, all living things were lumped together into two kingdoms, namely
plants and animals (at least, that's how I learned it). Animals included every living thing
that moved, ate, and grew to a certain size and stopped growing. Plants included every
living thing that did not move or eat and that continued to grow throughout life. It
became very difficult to group some living things into one or the other, so early in the
past century the two kingdoms were expanded into five kingdoms: Protista (the singlecelled eukaryotes); Fungi (fungus and related organisms); Plantae (the plants); Animalia
(the animals); Monera (the prokaryotes). Many biologists now recognize six distinct
kingdoms, dividing Monera into the Eubacteria and Archeobacteria.
All I can say is that the sytem holds true for this week, at least. It might even hold up for
a century or two. Accepted systems of classification have changed at a far faster pace
than the species have taken to evolve, that's for certain.
Kingdoms are divided into categories called phyla, each phylum is divided into classes,
each class into orders, each order into families, each family into genera, and each genus
into species. A species represents one type of organism, such as dog, tiger shark,
Ameoba proteus (the common amoeba), Homo sapiens (us), or Acer palmatum
(Japanese maple). Note that species names should be underlined or written in italics.
Classifying larger organisms into kingdoms is usually easy, but in a microenvironment
it can be tricky. If you have had a little biology, a good exercise is to describe individual
living things, and to try to classify them as to kingdom.
Monera (includes Eubacteria and Archeobacteria)
Individuals are single-celled, may or may not move, have a cell wall, have no
chloroplasts or other organelles, and have no nucleus. Monera are usually very tiny,
although one type, namely the blue-green bacteria, look like algae. They are filamentous
and quite long, green, but have no visible structure inside the cells. No visible feeding
mechanism. They absorb nutrients through the cell wall or produce their own by
photosynthesis.
Protista
Protists are single-celled and usually move by cilia, flagella, or by amoeboid
mechanisms. There is usually no cell wall, although some forms may have a cell wall.
They have organelles including a nucleus and may have chloroplasts, so some will be
green and others won't be. They are small, although many are big enough to be
recognized in a dissecting microscope or even with a magnifying glass. Nutrients are
acquired by photosynthesis, ingestion of other organisms, or both.
Fungi
Fungi are multicellular,with a cell wall, organelles including a nucleus, but no
chloroplasts. They have no mechanisms for locomotion. Fungi range in size from
microscopic to very large ( such as mushrooms). Nutrients are acquired by absorption.
For the most part, fungi acquire nutrients from decaying material.
Plantae
Plants are multicellular and most don't move, although gametes of some plants move
using cilia or flagella. Organelles including nucleus, chloroplasts are present, and cell
walls are present. Nutrients are acquired by photosynthesis (they all require sunlight).
Animalia
Animals are multicellular, and move with the aid of cilia, flagella, or muscular organs
based on contractile proteins. They have organelles including a nucleus, but no
chloroplasts or cell walls. Animals acquire nutrients by ingestion.
A "mini-key" to the five kingdoms
Suppose you see something in freshwater that certainly appears to be living. How can
you begin to determine what it is? Here is a key (not quite perfect) that you might use to
help determine the kingdom to which it belongs.




1. Is it green or does it have green parts?
o Yes - go to 2
o No - go to 3
2. Could be a plant or a protist, or blue-green bacteria. Make sure that the green
is really part of the organism, though. An animal might have eaten something
green, for example.
o Single-celled? go to 6
o Multicellular? Plantae. Look for cell walls, internal structure. In the
compound microscope you might be able to see chloroplasts.
3. Could be a moneran (bacteria), protist, fungus, or animal.
o Single-celled - go to 4
o Multicellular (Look for complex or branching structure, appendages) go to 5
4. Could be a moneran or a protist. Can you see any detail inside the cell?
o Yes - Protista. You should be able to see at least a nucleus and/or
contractile vacuole, and a definite shape. Movement should be present,
using cilia, flagella, or amoeboid motion. Cilia or flagella may be
difficult to see.
o No - Monera. Should be quite small. May be shaped like short dashes
(rods), small dots (cocci), or curved or spiral shaped. The largest them
that is commonly found in freshwater is called Spirillum volutans. It is
spiral shaped, and can be nearly a millimeter long. Except for Spirillum,


it is very difficult to see Monerans except in a compound microscope
with special lighting.
5. Animalia or Fungi. Is it moving?
o Yes - Animalia. Movement can be by cilia, flagella, or complex,
involving parts that contract. Structure should be complex. Feeding
activity may be obvious.
o No - Fungus. Should be branched, colorless filaments. May have some
kind of fruiting body (mushrooms are a fungus, don't forget). Usually
attached to some piece of decaying matter - may form a fuzzy coating on
or around an object. In water, some bacterial infections of fish and other
animals may be mistaken for a fungus.
6. Most likely Protista. If it consists of long, unbranched greenish filaments with
no apparent structure inside, it is blue-green bacteria (sometimes mistakenly
called blue-green algae), a Moneran.
Most green protists are flagellates, that is, they move rapidly with a spiralling motion.
Unless you get them to stop, you can't really see the flagella. Watch out for colonial
protists, though, such as Volvox, which forms a spinning ball of green cells. Don't be
fooled into thinking it is a plant.
Remember, the more you observe the organism, the more sure you can be. Many living
things have stages that make them resemble members of another kingdom.
http://www.ruf.rice.edu/~bioslabs/studies/invertebrates/kingdoms.html 18/12/2010
Taxonomy
Taxonomy is the classification of organisms. The most common system in use today is the Five
Kingdoms system of classification. In this system all organisms are divided into five kingdoms: Monera
(Prokaryota), Protista, Fungi, Plantae, and Animalia. Organisms in each kingdom are divided into phyla.
In each phylum, organisms are separated into classes. In each class, organisms are segregated into orders.
In each order, organisms are divided into families. In each family, organisms are separated by genus.
And finally, in each genus organisms are divided into species. Just remember that King Philip Can Order
For German Students.
Kingdom Monera
All organisms in the Kingdom Monera are prokaryotes. They lack nuclei and organelles and most of their
cell walls are made of peptidoglycan (the exceptions are the archaebacteria). Most utilize flagella for
movement.
Digestion is extracellular (outside the cell) and nutrients are absorbed into the cell. Many prokaryotes are
organized by how the metabolize resources. Autotrophs manufacture their own organic compounds.
Heterotrophs obtain their energy by feeding on other organic substances. Saprophytes, a special kind of
heterotroph, obtain energy by feeding on decaying matter. Some bacteria live in symbiotic relationships
with other organisms. In parasitism, harm is caused to the host. In commensalism, one organism
benefits while the other is unaffected. In mutualism, both organisms benefit.
Circulation and digestion in Kingdom Monera is accomplished through diffusion.
Respiration in these organisms vary. In obligate aerobes, the prokaryotes must have oxygen to live. In
obligate anaerobes, the organisms cannot survive in the presence of oxygen. And in facultative
anaerobes they can survive with or without oxygen.
Most organisms in the Kingdom Monera reproduce through binary fission (asexual) or conjugation
(sexual).
Recently, biologists have identified two distinct groups within Monera.
The archaebacteria have cell walls that lack peptidoglycan, cell membranes that utilize different lipids,
and ribosomes similar to those found in eukaryotes.
The eubacteria ("true bacteria") are characterized by how they metabolize resources, their means of
motility, and their shape. The three basic shapes are cocci (spherical), bacillus (rod shaped), and
spirillum (spirals).
Kingdom Protista
Protists are grouped according to whether they are animal-like, plant-like, or fungus-like.
Animal-like protists are called protozoans. They are unicellular and parasitic. Digestion in protozoans
is intracellular. Circulation, respiration, and excretion are accomplished through diffusion. Most
reproduce through binary fission (asexual) although some utilize conjugation (sexual).
Plant-like protists contain chlorophyll. They are both unicellular and multicellular (although multicellular
forms have no organs or tissues).






Members of Phylum Chlorophyta are the most modern and have chlorophyll a, b, and carotene.
Members of Phylum Chrysophyta are unicellular, golden algae.
Members of Phylum Phyrrophyta are unicelluar, fire algae with flagella.
Members of Phylum Phaeophyta are multicellular, brown algae.
Members of Phylum Rhodophyta are multicellular, red algae.
Members of Phylum Euglenophyta live in freshwater.
Fungus-like protists are divided into three groups: mxyomycota ("plasmodial slime molds"),
acrasiomycota ("cellular slime molds"), and oomycetes ("mildews and water molds"). Circulation,
respiration, and excretion are all accomplished through diffusion. Reproduction can be asexual through
fragmentation and the production of spores or sexual through conjugation and alternation of
generations
Kingdom Fungi
In general, fungi are multicellular, parasitic or saprophytic, and have cell walls made of chitin. Digestion
is extracellular. Rhizoids secrete enzymes and reabsorb the digested nutrients. Circulation, respiration,
and excretion occur through diffusion. Reproduction can be asexual through spores or sexual where
strains of fungi meet.
Kingdom Plantae
In general, all plants have chlorophyll, cell walls of cellulose, and tissues and organs. Biologists have
theorized that plants evolved from algae since both plants and algae have chloroplasts with chlorophyll,
cell walls of cellulose, glucose stored as starch, and alternation of generations.
Plants are classified in the following divisions:

Division Bryophyta- plants are primitive and lack vascular tissue and true roots. Examples
include mosses and liverworts.

Super Division Tracheophyta- plants are more advanced and contain vascular tissue.

Division Pterophyta- plants reproduce by spores and grow from underground stems. Example
include ferns and horsetails.

Division Coniferophyta- plants produce naked seeds in cones and soft wood. Many are
evergreens. Examples include redwoods, pines, cypress, and junipers.

Division Anthophyta- plants are the most advanced and produce flowers. Class
monocotyldonae plants have seeds that contain one cotyledon, leaves with parallel veins, flower
parts in multiples of three, no cambium, and scattered vascular bundles in the stem. Class
dicotyledonae plants have seeds that contain two cotyledons, leaves with netted veins, flower
parts in multiples of four and five, cambium, and vascular bundles in a cylinder.
 Kingdom Animalia
Animals are heterotrophic, multicellular organisms with organs or tissues. Most are mobile or
have a mobile life stage. All have a larval or embryonic stage of development.
Animals also exhibit different kinds of symmetry: asymmetry, spherical, radial, and bilateral.
Finally, animals can be invertebrates (no backbone) or vertebrates (with backbone).
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Source: O'Neil, Dennis, Behavioral Sciences Department, Palomar College. 2010
http://anthro.palomar.edu/animal/table_kingdoms.htm 14-12-2010
KINGDOMS OF LIVING THINGS
IN THE LINNAEAN CLASSIFICATION SYSTEM
KINGDOM
Monera
STRUCTURA
L
ORGANIZATI
ON
small, simple
single
prokaryotic
cell (nucleus is
not enclosed
by a
membrane);
some form
chains or mats
METHOD OF
NUTRITION
TYPES OF
ORGANISMS
absorb food
and/or
photosynthesi
ze
bacteria,
blue-green
algae, and
spirochetes
NAMED
SPECIES
4,000
TOTAL
SPECIES
(estimate)
1,000,000
Protista
large, single
eukaryotic cell
(nucleus is
enclosed by a
membrane);
some form
chains or
colonies
absorb,
ingest, and/or
photosynthesi
ze food
protozoans
and algae of
various types
80,000
600,000
Fungi
multicellular
filamentous
form with
specialized
eukaryotic
cells
absorb food
funguses,
molds,
mushrooms,
yeasts,
mildews, and
smuts
72,000
1,500,000
Plantae
multicellular
form with
specialized
eukaryotic
cells; do not
have their own
means of
locomotion
photosynthesi
ze food
mosses,
ferns, woody
and nonwoody
flowering
plants
270,000
320,000
Animalia
multicellular
form with
specialized
eukaryotic
cells; have
their own
means of
locomotion
ingest food
sponges,
worms,
insects, fish,
amphibians,
reptiles,
birds, and
mammals
1,326,239
9,812,298
NOTE: A growing number of researchers now divide the Monera into two distinct kingdoms:
Eubacteria (the true bacteria) and Archaebacteria (bacteria-like organisms that live in extremely
harsh anaerobic environments such as hot springs, deep ocean volcanic vents, sewage
treatment plants, and swamp sediments). Viruses, prions, and other non-cellular organic entities
are not included in the kingdoms of living things.
The numbers of named and estimated total species were derived from Gibbs, W. Wayt (2001)
"On the Termination of Species", Scientific American Vol. 285, No. 5.
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Source: http://teachers.oregon.k12.wi.us/hanson/index2.htm
Characteristics of
monerans
A. One-celled
organisms
B. Cells have no
membrane around the
nucleus
C. Reproduce by
splitting in two
D. Absorb nutrients
from outside their
bodies
E. Some monerans
cause diseases, but
others are helpful to
people
F. Examples: bacteria
Characteristics
of protists
A. Most are onecelled, but some
have many cells
B. Cells have a
membrane
around the
nucleus
C. Some get
nutrients and
energy by eating
other organisms
D. Some get
energy from the
sun, and
nutrients from
the water
around them
E. Most
reproduce by
splitting in two
F. Examples are
paramecium,
amoeba, and
kelp
Characteristics of fungi
A. Most are many-celled
and some are one-celled
organisms
B. Cells have a
membrane around the
nucleus
C. Get nutrients and
energy by absorbing/
digesting the surface they
live on
D. Most reproduce by
spores
E. Examples are yeast,
mushrooms, bread molds,
and lichens
Pictures of fungi
Characteristics of plants
A. Many-celled
organisms
B. Cells have a
membrane around the
nucleus, contain
chlorophyll, and have
cell walls
C. Get energy from the
sun and take in
nutrients from their
surroundings
D. Most reproduce from
seeds; some reproduce
from other special parts
E. Examples are ferns,
trees, grasses, and
bushes
Characteristics of
animals
A. Many-celled
organisms
B. Cells have a
membrane
around the
nucleus
C. Get nutrients
and energy by
eating other
organisms
D. Reproduce
with eggs. Some
eggs develop
inside the
mother's body,
and some
develop outside
the mother's
body.
E. Examples are
bears, fish, frogs,
butterflies, and
starfish
Pictures of Animals
Monerans Protists Fungi Plants Animals
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Source: http://train-srv.manipalu.com/wpress/?p=86485 18-12-2010
BO0036-Unit-01-Overview of Plant
Biology
Unit-01-Overview of Plant Biology
Structure:
1.1 Introduction
Objectives
1.2 Classification of Organisms
1.3 Five Kingdom Classification
1.4 The Plant Kingdom
1.5 Branches of Plant Biology
1.6 Binomial Nomenclature
1.7 Summary
1.8 Terminal Questions
1.9 Answers
1.1 Introduction
Man has always been impressed by the vastness and variety of living things. Plants and
animals are the main livings things dominated on earth. Though some small
microscopic organisms have been claimed as plants by the botanists and as animals by
the zoologists, the higher plants may be readily distinguished from the higher animals.
This unit takes you through the scope and importance of plant biology, overview of
classification of plant kingdom, branches of plant biology and eventually into binomial
nomenclature which is essential to understand plant taxonomy.
Objectives:
After studying this unit, you should be able to:
· discuss the scope and importance of plant biology
· describe the system of classification of plant kingdom
· list the branches of plant biology
· define binomial nomenclature.
1.2 Classification of Organisms
Current systems of classifying forms of life descend from the thought presented by the
Greek philosopher Aristotle (384 B.C. to 322 B.C.), who published in his works the
first known classification of everything whatsoever, or "being". This is the scheme that
gave such words as ’substance’, ’species’ and ‘genus’ and was retained in modified and
less general form by Linnaeus. Aristotle is also called “Father of Biological
Taxonomy”.
Since late in the 15th century, a number of authors had become concerned with what
they called methodus (method). By method authors mean an arrangement of minerals,
plants, and animals according to the principles of logical division. The term Methodists
was coined by Carolus Linnaeus in his Bibliotheca Botanica to denote the authors who
care about the principles of classification (in contrast to the mere collectors who are
concerned primarily with the description of plants paying little or no attention to their
arrangement into genera, etc). Important early Methodists were Italian philosopher,
physician, and botanist Andrea Caesalpino, English naturalist John Ray, German
physician and botanist Augustus Quirinus Rivinus, and French physician, botanist, and
traveller Joseph Pitton de Tournefort.
Carlous Linnaeus (1707-1778), also referred as “Father of Classification”, divided the
living organisms in to two kingdoms – Animalia for animals and Vegetabilia for plants
(Linnaeus also included minerals, placing them in a third kingdom, Mineralia).
Linnaeus divided each kingdom into classes, later grouped into phyla for animals and
divisions for plants. He published his work in “Systema Naturae” (1758). He also
introduced the Binomial System of nomenclature, which would be discussed later in this
unit.
1.3 Five Kingdom Classification
The present trend in biology is to follow the five kingdom classification proposed by
Robert. H. Whittaker in the year 1969. Whittaker classified the living organisms into
five kingdoms namely.
1. Kingdom: Monera (prokaryotic organisms)
2. Kingdom: Protista (primitive eukaryotic organisms)
3. Kingdom: Mycota (exclusively fungi)
4. Kingdom: Metaphyta (advanced eukaryotic plants)
5. Kingdom: Metazoa (all multicellular animals)
According to this classification, Monera represent the earliest group of organisms. The
Monera are thought to have given rise to Protista from which the three other kingdoms
of organisms namely, the fungi, plants and animals evolved along separate lines
(fig.1.1). Fungi were the first to appear from Protista. Later, about a billion years ago
some protists must have evolved into primitive multicellular animals. Still later,
probably about 350 million years ago, some protists must have evolved into higher
forms of plants.
Fig. 1.1: Five Kingdom Classification
Following table includes the characteristic features of five kingdoms:
Merits and Demerits of Five Kingdom Classification
The five-kingdom classification has certain merits and demerits. However, it is largely
the most accepted system of modern classification mainly because of the phylogenetic
placing of different groups of living organisms.
· Separation of prokaryotes into an independent kingdom is justifiable because they
differ from all other organisms in their general organization.
· Grouping of all unicellular eukaryotes under the kingdom Protista has solved many
problems, particularly related to the position of organisms like Euglena.
· Elevation of the group fungi to the status of a kingdom is justifiable since fungi totally
differ from other primitive eukaryotes like algae and protozoans.
· The kingdoms Metaphyta and Metazoa are now more homogenous groups than they
were in the two kingdom classification as it shows the phylogeny of different life styles.
· The five-kingdom classification gives a clear indication of cellular organization and
modes of nutrition, the characters which appeared very early in the evolution of life.
However, the five-kingdom classification has certain drawbacks also, particularly with
reference to the lower forms of life.
· The kingdoms Monera and Protista include diverse, heterogeneous forms of life. In
both the kingdoms there are photosynthetic (autotrophic) as well as non-photosynthetic
(heterotrophic) organisms.
· Both the kingdoms include organisms which have cells with cell wall as well as
without cell wall.
· None of the three higher kingdoms include a single ancestor of all its forms.
Multicellular lines have originated from protistans several times (polyphyletic).
· Unicellular green algae like Volvox and Chlamydomonas have not been included under
Protista because of their resemblance to other green algae.
· Slime moulds differ totally from other members of Protista in their general
organization.
· Viruses have not been given proper place in this system of classification.
· Nevertheless, the five-kingdom classification has found a wide acceptance with
biologists all over the world.
1.4 The Plant Kingdom
Quite a large number of plants exist in this world of nature. More than 3, 50,000 plants
have been identified, described and named by the botanists and a pretty large number
still remain unknown. Thus they are not only large in number, but are equally varied in
nature. They inhabit all the conceivable places in the world and can often withstand
extreme unfavourable conditions. The smallest bacteria, which occur everywhere and
some of which are the causes of many diseases we suffer from, are plants and form one
extreme, and the gigantic forest trees form the other. Transitional stages between the
two extremes are numerous. The problem is really a stupendous one and it cannot be
tackled unless a suitable and systematic pla/n of dividing the plant kingdom into smaller
and smaller groups is devised. Attempts to classify plants were made even by the early
ancients like Theophrastus in Greece and the Indian sages in the ages of the Upanishads.
Since the sixteenth century, different systems of classification have been proposed.
Modern classification is truly systematic, as it is based on the interrelationships amongst
the plant groups.
Plant Kingdom is broadly divided into four groups, viz. Thallophyta, Bryophyta,
Pteridophyta and Spermatophyta. Of the four groups the first three never bear flowers as
they are popularly known as Cryptogams or flowerless plants. The last group includes
the plants which bear flowers and are also known as flowering plants or Phenerogams.
It is considered now that pteridophyta is not a homologous group and a clear line of
demarcation hardly exists between pteridophyta and the next higher group
spermatophyta. In view of above consideration which is based on a sound study of
fossils and living plants, it is advocated that all vascular plants, naturally including
pteridophytes and spermatophytes, should be put under the group Tracheophyta.
I. Thallophyta
Plants belonging to this group are the simplest and most primitive ones. Their bodies are
not differentiated into organs like root, stem and leaf. In fact, the plant body of a
thallophyte is an undifferentiated mass of cells, known as a thallus. A thalloid body may
be unicellular or a colony of cells which does not exhibit any division labour. The sex
organs are usually unicellular.
(a) Algae:
The green thallophytes possessing chlorophyll are known as Algae. They usually grow
in water or in moist situations. Some marine algae like the sea-weeds and arid kelps are
fairly large in size. In addition to chlorophyll, other pigments may also be present in
algae. The fresh-water algae are generally green or blue-green in colour, whereas the
marine ones are red or brown. These are autotrophic plants, as they can manufacture
their own food.
Classification of Algae:
F.E. Fritsch, the well-known algologist of the Great Britain, has published two volumes
of books on Structure and Reproduction of the algae in 1935 and 1945 and discussed his
own system of classification for algae in it. Fritch’s system of classification is based on
chemical nature of pigments, mode of attachment of flagella in the motile cells, range of
thallus structures, methods of reproduction and patterns of life cycle.
Based on these characters Fritsch’s System of Classification of Algae consists of 11
classes, they are:
1. Chlorophyceae: Chlorophyll – a, Chlorophyll –b, Xanthophyll and Carotenes –
photosynthesis food products are starch. The flagellation is isokontean type – both of
the flagella are equal in length. Sexual reproduction ranges from isogamy to oogamy.
Life cycle-Haplontic type.
2. Xanthophyceae: Chlorophyll – a, Carotenes and Xanthophyll – food products are
oils. The flagellation is Heterokontean type. – One flagellum is short and other long.
Life cycle-Haplontic type.
3. Chrysophyceae: Chlorophyll – a, Chlorophyll – c, and ß – Carotenes – food products
are Chrysolaminarin and oils. Flagella two, dissimilar.
4. Bacillariophyceae: Chlorophyll-a, ß – carotene and Xanthophylls – food products
are fats or volutins. Flagella 1 to 2, Sexual reproduction – special type – auxospores
formation. Life cycle-diplontic.
5. Cryptophyceae: Unicellular – Heterotrophs and some form symbiotic associations
with coelenterates.
6. Dinophyceae: Planktonic unicellular algae, Biflagellate, with one flagellum
encircling the cell, the other trailing backwards – food products oil, fucoxanthin
pigment, sexual reproduction oogamous.
7. Chloromonadineaceae: Unicellular – flagellate – chlorophyll – a, Carotene
8. Euglenophyceae (Eugleniaceae): Unicellular motile – no cell wall – two flagella –
one reduced. Pigments chlorophyll – a, Chlorophyll – b and ß – Carotene – food
products paramylum. There is no known sexual reproduction.
9. Phaeophyceae : Chlorophyll – a and ß – carotene – food products are alcohols,
mannitol and laminarin. Motile reproductive cells are pyriform. Sexual reproduction
ranges from isogamy to oogamy. Mostly marine species.
10. Rhodophyceae: Chlorophyll –a, ß – carotene, Xanthophylls,
γ – phycoerythrin and c – phycocyanin pigments. Food products polysaccharides,
floridean starch. The flagellation is absent. Sexual reproduction is advanced type. The
life cycle shows alternation of generations. Some fresh water and most of them are
marine species.
11. Myxophyceae (Cyanophyceae): The main pigments are chlorophyll – a, ß –
Carotene, Xanthophylls, C – phycocyanin and c – phycoerythrin – food products are
sugars and cyanophycean starch. Flagella absent. Sexual reproduction is unknown.
Mostly fresh water species.
(b) Fungi:
Non-green thallophytes characterized by total absence of chlorophyll are called Fungi.
They grow either on dead, rotten organic matters as saprophytes or live as parasites on
other living bodies, which are referred to as hosts. Moulds and mushrooms are the
familiar examples of saprophytic fungi. Parasitic fungi infect a pretty large number of
economic plants as well as animals and often cause considerable damage.
Classification of Fungi:
Fungi are eukaryotic micro organisms lacking chlorophyll. The plant body is called
mycelium which is made up of thread like filaments known as hyphae. They include
such well known forms as mushrooms, toadstools, puff balls, shelf-fungi, moulds,
mildews, rusts and smuts. The group fungi include more than 4,000 genera 100,000
species.
The Eumycophyta are the true fungi and it is divided into four classes:
(Gwynne-Vaughan and Barnes-1926)
Class Phycomycetes: Except for the most primitive members, which are unicellular,
the mycelium is aseptate and the spores are produced in indefinite numbers within a
sporangium. The Phycomycetes is further divided into three subclasses:
Archimycetes (3 orders), Oomycetes (5 orders) and zygomycetes (2 orders).
Class Ascomycetes: The mycelium is septate and the characteristic reproductive body
is the Ascus. Inside ascus, usually 8 ascospores are produced. The class Ascomycetes is
further divided into 3 sub-clases:Plectomycetes Eg : Penicilium (3 orders)
Discomycetes Eg : Peziza (5 orders)
Pyrenomycetes Eg : Xylaria (4 orders).
Class Basidiomycetes : The mycelium is septate and the characteristic reproductive
body is Basidium. This produces typically 4 basidiospores, exogeniously. The class
Basidiomycetes is divided into 3 sub-classes: Hemibasidiomycetes (1 order),
protobasidiomycetes Eg : Puccinia (3 orders)
Autobasidiomycetes Eg : Agaricus (2 orders)
Class Deuteromycetes (or Fungi Imperfecti):- In the members of this class, neither
ascospore nor basidiospore is found to be produced. The sexual stage is absent or
unknown. This is an artificial group and is created provisionally. This class includes 4
orders.
A new system of classification of Fungi has been proposed by Alexopoulos, which is as
follows.
Kingdom: Myceteae with 3 divisions.
1. Gymnomycota
2. Mastigomycota
3. Amastigomycota
Division-1: Gymnomycota is characterized by the presence of amoeboid somatic cells,
lack cell wall, saprophytic, and reproduce by spores. The members come under protista
as per five kingdom classification.
This division consists of 2 sub – divisions.
1. Acrasiogymnomycotina – Characterised by Myxamoeba, pseudoplasmodium
develops fruiting body that bears spores.
2. Plasmodiogymnomycotina: Myxamoeba fuses to form a true plasmodium.
This sub–division consists of two classes viz. Prosteliomycetes & Myxomycetes
Division-2: Mastigomycota: The division consists of 2 sub-divisions.
Sub-division-1. Haplomastigomycotina: Includes various flagellate fungi, life cycle
Haplobiontic or Diplobiontic.
This sub–division includes three classes viz. Chytridiomycetes, Hypochytridomycetes,
Plasmodiophoromycetes.
Division-3: Amastigomycota: Motile cells are lacking, asexual reproduction by
budding, fragmentation, and conidia; sexual reproduction by various means.
This division is classified into 4 sub-divisions viz. Zygomycotina, Ascomycotina,
Basidiomycotina and Deuteromycotina.
(c) Lichens:
Lichens are composite organisms consisting of a symbiotic association of a fungus (the
mycobiont) with a photosynthetic partner (the photobiont or phycobiont), usually either
a green alga (commonly Trebouxia) or cyanobacterium (commonly Nostoc). The
morphology, physiology and biochemistry of lichens are very different from those of
the isolated fungus and alga in culture. Lichens occur in some of the most extreme
environments on Earth – arctic tundra, hot deserts, rocky coasts and toxic slag heaps.
However, they are also abundant as epiphytes on leaves and branches in rain forests and
temperate woodland, on bare rock, including walls and gravestones and on exposed soil
surfaces (e.g. Collema) in otherwise mesic habitats. Lichens are widespread and may be
long-lived; however, many species are also vulnerable to environmental disturbance,
and may be useful to scientists in assessing the effects of air pollution, ozone depletion,
and metal contamination. Lichens have also been used in making dyes and perfumes, as
well as in traditional medicines.
Classification of Lichens:
Lichens are informally classified by growth form into crustose (paint-like, flat), e.g.,
Caloplaca flavescens ; filamentous (hair-like), e.g., Ephebe lanata; foliose (leafy), e.g.,
Hypogymnia physodes; fruticose (branched),
e.g., Cladonia evansii, C. subtenuis, and Usnea australis; leprose (powdery), e.g.,
Lepraria incana ; squamulose (consisting of small scale-like structures, lacking a lower
cortex), e.g., Normandina pulchella ; gelatinous lichens, in which the cyanobacteria
produce a polysaccharide that absorbs and retains water.
Lichens are also named based on the fungal component, which plays the primary role in
determining the lichen’s form. The fungus typically comprises the majority of a lichen’s
bulk, though in filamentous and gelatinous lichens this is not always the case. The
lichen fungus is typically a member of the Ascomycota – rarely a member of the
Basidiomycota, and then termed basidiolichens to differentiate them from the more
common ascolichens. Formerly, some lichen taxonomists placed lichens in their own
division, the Mycophycophyta, but this practice is no longer accepted because the
components belong to separate lineages.
II. Bryophyta
This group consists of plants which are more advanced than the thallophytes. They
usually grow in moist places. Some bryophytes like the liverworts have thalloid bodies,
whereas the mosses show slight differentiation of plant body. In fact, in a moss the plant
body is differentiated into a small stem and simple leaves, but true roots are absent. The
sex organs are multicellular and the gametes always remain surrounded by a jacket of
sterile cells.
Classification of Bryophytes:
Bryophytes are land – inhabiting plants and are compared to the Amphibia of the
Animal Kingdom. There are 960 genera and 24,000 species of bryophytes.
Classification of Bryophytes by Rothmaler (1951) was recognized by the International
Code of Botanical Nomenclature, which is as follows:
The Division-Bryophyta has three classes viz. Hepaticopsida, Anthocerotopsida and
Bryopsida.
Class-1: Hepaticopsida
Characterized by dorsiventral gametophytes, sporophyte simple and completely
dependent on gametophyte for its nutritional supply. The dehiscence of sporogonium is
irregular. Eg. Riccia
The class Hepaticopsida is further divided into following orders:
1. Sphaerocarpales 2. Marchantiales 3. Metzgeriales
4. Jungermanniales 5. Calobryales 6. Takakiales
Class-2: Anthocerotopsida
Characterized by dorsiventral gametophytes – Sex organs are embedded in the
gametophytic tissue – sporogonium contains chlorophyll – sporogonium contain
meristematic region. The class includes 2 families – Anthocerotaceae and
Notothylaceae. Eg. Anthoceros
Class-3: Bryopsida – The gametophyte is characterized by erect plant body with
rhizoid, stem, spirally arranged leaves and the sex organs at the apical region of stem.
The sporophyte is differentiated into foot, seta and capsule. Eg. Funaria
This class has been divided into 3 sub-classes viz. Sphagnobrya, Andreaeobrya and
Eubrya.
III. Pteridophyta
This group includes the vascular cryptogams like club-mosses, horsetails and ferns
which are universally distributed all over the world. Most of them are terrestrial plants
flourishing well in moist and shady places, and some of them are aquatic. The
pteridophytes have well-differentiated plant bodies, consisting of roots, stems and
leaves. Moreover, they possess vascular bundles. The sex organs are multicellular and
the gametes remain surrounded by sterile cells.
Classification of Pteridophytes:
The pteridophytes are seedless plants with vasculature. They possess xylem and phloem
for conduction. The pteridophytes have originated during Devonian period of Paleozoic
era. The pteridophytes are represented today by over 13,000 living species belonging to
400 genera.
Reimers (1954) classification of pteridophyta is as follows:
Class 1: Psilophytopsida – Includes most primitive fossil vascular cryptogams. Order:
Psilophytales(Fossils) Eg. Rhynia, Asteroxylon
Class 2: Psilotopsida- includes most primitive living vascular cryptogams.
Order: Psilotales eg. Psilotum.
Class 3: Lycopsida: Includes both living and fossil pteridophytes . The living members
are commonly called club – mosses.
This class has 5 orders viz. Protolepedendrales (fossils), Lepidodendrales (fossils),
Lycopodiales eg. Lycopodium, Selaginellales eg, Selaginella, Isoetales eg. Isoetes
Class 4: Sphenopsida: This class includes both living and fossil pteridophytes. The
living members are commonly called horsetails.
This class has 4 orders viz. Hyeniales (Fossils), Sphenophyllales (fossils) eg.
Sphenophyllum, Calamitales (Fossils) eg. Calamites, Equisetales
eg Equisetum.
Class 5 : Pteropsida: It is the most highly evolved pteridophytes. This group includes
the most familiar pteridophytes called ferns. This class is divided into 4 sub-classes.
Sub-class 1: Primofilicales (fossils) with orders viz. Cladoxylales, and Coenopteridales
Sub-class 2: Eusporangiatae with orders Marattilaes eg. Angiopteris, and
Ophioglossales eg Ophioglossum.
Sub-class 3: Osmundidae with order Osmundales eg: Osmunda
Sub-class 4 : Leptosporangiatae with orders viz. Flicales eg, Adiantum, Marsileales eg,
Marsilea, and Salviniales eg, Salvinia.
IV. Spermatophyta. The so-called higher plants belong to this group. Apart from
distinct differentiation of the plant body like the pteridophytes, development of typical
flowers and consequent reproduction through seeds are the outstanding features of this
group. Spermatophytes are again divided into two groups, viz., Gymnosperms and
Angiosperms.
(a) Gymnosperms:
Gymnosperms are the naked-seeded plants. They have very simple flowers without
accessory whorls and the microsporophylls (stamens) and megasporophylls (carpels)
remain aggregated in cones. Ovules are present on the surface of the megasporophylls
and are directly pollinated by the pollen grains. There is nothing like ovary, style and
stigma, and naturally there is no fruit. Gymnosperms constitute a group intermediate
between pteridophytes and angiosperms.
Classification of Gymnosperms:
Gymnosperms are a diverse group of vascular plants and they possess seeds borne
naked on a sporophyll and not in an ovary. There are about 70 genera and 725 living
species of gymnosperms.
Sporne (1965) classified Gymnosperms into 3 Classes.
Class-1: Cycadopsida with 4 orders Pteridospermales, Bennettitales, Pentoxylales and
Cycadales. The class Cycadopsida is characterized with plants are palm – like, leaves
pinnate with central midrib; megasporophylls are not aggregated in cones, but borne
separately like foliage leaves; Megasporophyll bears two or more ovules.
Microsporophylls aggregate to form male cone. Eg. Cycas
Class-2: Coniferopsida with 4 orders Cordaitales, Coniferales, Taxales and Ginkgoales.
This class is characterized with mostly ever green trees, leaves are needle or scale like,
wood contains resin canals, male and female cones are present. Eg. Pinus
Class-3: Gnetopsida with only one order Gnetales: This class is characterized with
trees, shrubs or woody climbers, vegetative appearance is mostly like angiosperm with
large leaves, oval and entire wood contain vessels. Male strobilus contains staminate
flower and female strobilus contain ovules. Eg.Gnetum
(b) Angiosperms:
Angiosperms are the close-seeded plants. These are the most highly developed plants
which bear flowers having conspicuous accessory and essential whorls. Carpels have
the ovary, style and stigma. With the stimulus of fertilization the ovary usually develops
into the fruit and the ovules into seeds. Thus the seeds remain within the fruits.
Angiosperms exhibit wide diversities as regards their form and structure, ranging from
the smallest duck-weeds to the huge forest trees; and they are capable of growing in all
types of situations. They are further put into two subdivision dicotyledons and
monocotyledens, depending on the number of cotyledons in the embryo.
Classification of Angiosperms:
There have been several attempts to classify angiosperms, the flowering plants. One of
the earliest attempts in this direction was that of Carolus Linnaeus. He attempted a
classification of angiosperms based on the characteristics related to flowers. Subsequent
taxonomists also have found that floral characteristics provide the main basis for
angiosperm classification.
Some of the earlier systems of classification of angiosperms can be described as
artificial systems, since they use only certain superficial characteristics as the basis.
However, with more and more detailed study on the morphological, physiological and
reproductive aspects of angiosperms, the artificial systems of classifications were
replaced by the natural systems of classification.
The natural systems of classification of angiosperms have mainly used the floral
characteristics as the basis. Some of the earlier attempts in this direction were those of
Linnaeus, John Ray, Bentham and Hooker. However, these systems of classification are
now termed as non-phylogenetic natural systems. Since the classification is not based
on evolutionary relationships. Different families have been placed in specific groups
which do not show evolutionary relationships. This was mainly because, many of these
systems of classification were put forth in the pre-Darwinian period, when the idea of
evolution was still being debated. Subsequent to the advent of Darwin’s theory of
Natural Selection, great interest was generated about evolution and scientists started
looking for evolutionary relationships between different groups of plants. This led to the
revision of classification systems. In the beginning of 20th century, one can see the
emergence of new systems of classification, purely based on evolutionary relationships.
These systems came to be known as Phylogenetic systems of natural classification. The
most significant among them is the system of classification proposed by two German
scientists Engler and Prantl in the year 1905. You would learn more about the Engler
and Prantl system of classification in Unit-4 of this Self Learning Material (SLM).
Self Assessment Questions
1. Systema Naturae was published by________________________.
2. Usnea is a/an _______.
a) Algae b) Fungi c) Lichen d) Bryophyte
3. Classification for Gymnosperms was given by_______________.
1.5 Branches of Plant Biology
Plant Biology or Botany is the science of plant life. As such it includes everything
which has reference to plants. It considers the external appearance of the plant organs,
their internal structure and organization, the various vital activities like nutrition,
respiration, growth, movement and reproduction carried on by plants, as well as a
systematic classification based on resemblances and differences, their life-histories,
their adaptations to varying environmental conditions, relationships amongst themselves
and with other living things, their distribution in the world in space and time and their
economic values specially to mankind.
As Plant biology or botany is a vast science embracing everything having connection
with plants, it is usually divided into a few branches or subdivisions for the convenience
of study.
· Morphology includes the study of the form and structure of the plant organs. The
gross external features that can be examined with the naked eye, come under external
morphology.
· Anatomy or Internal morphology deals with the internal structures. The aid of the
magnifying apparatus, microscope, is indispensable for the study of internal structures
and other minute details.
· Histology is the study of minute structures. So it forms a part of anatomy.
· Cytology is the special study of the cell, the unit of structure and function.
· Physiology deals with the vital functions performed by the plants. It seeks to explain
the processes like metabolism, growth, movement and reproduction.
· Taxonomy or systematic biology is concerned with the classification of plants or
division of the plant kingdom into smaller and smaller groups in a systematic manner,
and with the naming of the plants for identification.
· Ecology considers the influence of environment or surroundings on plants and plant
communities and the various adaptations exhibited by them according to the situations
where they grow,
· Plant geography is the study of the distribution of plants in the different parts of the
world and the factors responsible for it.
· Paleobotany considers the distribution of plants in time. This study is based on the
fossil remains of the plants that existed in the dim past.
· Genetics is a modern science dealing with study of heredity in plants.
Like other natural sciences, plant biology may also be studied from two- aspects – pure
and applied.
The subdivisions stated above belong to Plant Biology, which are concerned with the
fundamental knowledge of the subject regardless of their practical application. Applied
branches are those which are particularly related to the well-being of mankind and thus
form part of economic botany. Agriculture dealing with the study of crop plants,
Horticulture concerned with the study of garden plants, Forestry, with the forest trees,
Pharmacognosy, with the drug plants, Plant pathology, with the plant diseases with
relevance suggestions about prevention and treatment, and Plant breeding are the
applied braches of plant biology. Besides these, special investigations of certain groups
of pants are also referred to as sub-sciences, viz., Algology, the study of algae;
Mycology, of fungi; Bacteriology, of bacteria and so on.
1.6 Binomial Nomenclature
It is the system of giving a scientific name to an animal or a plant, an outstanding
system contributed by Carolus Linnaeus. According to this system, any given animal
or plant is given a scientific name consisting of two words. The first word refers to
name of the genus while the second word refers to the name of the species. Both the
genus and the species are generally given Latin names. Greek words are quite prevalent
though Latin grammar is used. In rare cases, even vernacular names have been
incorporated into the scientific name. For example, Pitta brachyura for the bird called
the Indian Pitta. The word Pitta being taken from Telugu. The name of the genus is
usually a noun and that of the species is an adjective. It is not unusual in Latin that an
adjective follows the noun.
Binomial nomenclature avoids the confusion of using common names. For example, the
mountain lion is commonly called as puma, cougar, panther and so on in different parts
of the world. However, scientists all over the world recognize this animal by a scientific
name Felis concolor. The domestic cat belongs to the same genus Felis but not to the
same species. Scientifically it is known as Felis domestica. Similarly the scientific name
of tiger is Felis tigris and that of lion is Felis leo. Similarly, the bread wheat is
scientifically called Triticum aestivum and duram wheat (used in bakery) is called
Triticum durum.
There are certain guidelines laid down with reference to the use of binomial
nomenclature which is the result of deliberations held from time to time. An
international committee has been established to frame the rules and regulations
regarding binomial nomenclature for plants and animals. It is known as the
International Council for Binomial Nomenclature (ICBN). Following are some of
the major guidelines for scientific naming of plants and animals.
1. Every scientific name should have words either in Latin or be Latinized (i.e., follow
Latin grammar).
2. The first word refers to name of the genus and the second word to the name of the
species.
3. The name of the genus should start with a capital letter and name of the species with
a small letter.
4. Both the names should be printed in italics or else they should be underlined
separately. For example, Felis leo or Felis leo.
5. Name of the scientist who first identified and described the species should be
abbreviated and written after the species name, preferably in brackets. For example,
Homo sapiens Linnaeus is written as Homo sapiens (Linn). This practice is more
prevalent in the botanical sciences.
Following table (Table 1.1) includes binomial nomenclature of some common plants
and animals.
Table 1.1: Binomial Nomenclature of some common plants and animals.
Systematic Position
Once an organism is identified and grouped, it is then described in terms of the various
taxonomic categories to which it belongs. Such a description is known as systematic
position or taxonomic hierarchy. Hierarchy includes Kingdom as a higher position and
species as a lowest position (Kingdom-Subkingdom-Phylum / DivisionSubphylum/Subdivision-Class Subclass- Order-Family-Genus-Species).
The following is a description of the systematic position of human being and the
hibiscus plant (Table 1.2).
Table 1.2: Systematic position of human being and the hibiscus plant.
Self Assessment Questions
4. Triticum aestivum is scientific name of__________.
5. Name of the genus should start with________ letter.
1.7 Summary
· Current systems of classifying forms of life descend from the thought presented by the
Greek philosopher Aristotle (384 B.C. to 322 B.C.)
· Carlous Linnaeus (1707-1778) also referred as “ Father of Classification”, divided
the living organisms in to two kingdoms – Animalia for animals and Vegetabilia for
plants (Linnaeus also included minerals, placing them in a third kingdom, Mineralia).
· Robert. H. Whittaker (1969) classified the living organisms into five kingdoms
namely Monera, Protista, Mycota, Metaphyta, Metazoa.
· Plant Kingdom is broadly divided into four groups, viz.Thallophyta, Bryophyta,
Pteridophyta and Spermatophyta. Of the four groups the first three never bear flowers as
they are popularly known as Cryptogams or flowerless plants. The last group includes
the plants which bear flowers and are also known as flowering plants or Phenerogams.
· Morphology, Anatomy, Histology, Cytology, Physiology, Taxonomy, Ecology, Plant
geography, Paleobotany, Genetics are the branches of Plant biology.
· Binomial Nomenclature is the system of giving a scientific name to an animal or a
plant, an outstanding system contributed by Carolus Linnaeus.
1.8 Terminal Questions
1. Explain the merits and demerits of Whittaker’s classification.
2. Briefly describe the Fritsch’s classification of Algae.
3. What are Lichens? Add note on their classification.
4. List the various branches of plant biology.
5. What is Binomial Nomenclature? Write a note on ICBN guidelines for scientific
naming of plants and animals.
1.9 Answers
Self Assessment Questions
1. Carlous Linnaeus
2. Lichen
3. Sporne
4. Wheat
5. Capital letter
Terminal Questions
1. Refer to Section 1.3
2. Refer to Section 1.4
3. Refer to Section 1.4 I (c)
4. Refer to Section 1.5
5. Refer to Section 1.6
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http://waynesword.palomar.edu/trfeb98.htm 30/12/2010
The Five Kingdoms Of Life
The Amazing Diversity Of Living Systems
L
iving organisms are subdivided into 5 major kingdoms, including the
Monera, the Protista (Protoctista), the Fungi, the Plantae, and the Animalia.
Each kingdom is further subdivided into separate phyla or divisions.
Generally "animals" are subdivided into phyla, while "plants" are subdivided
into divisions. These subdivisions are analogous to subdirectories or folders
on your hard drive. The basic characteristics of each kingdom and
approximate number of species are summarized in the following table:
Prokaryotic Cells Without Nuclei And Membrane-Bound Organelles
1. Kingdom Monera [10,000 species]: Unicellular and colonial--including the
true bacteria (eubacteria) and cyanobacteria (blue-green algae).
Eukaryotic Cells With Nuclei And Membrane-Bound Organelles:
2. Kingdom Protista (Protoctista) [250,000 species]: Unicellular protozoans and
unicellular & multicellular (macroscopic) algae with 9 + 2 cilia and flagella
(called undulipodia).
3. Kingdom Fungi [100,000 species]: Haploid and dikaryotic (binucleate) cells,
multicellular, generally heterotrophic, without cilia and eukaryotic (9 + 2)
flagella (undulipodia).
4. Kingdom Plantae [250,000 species]: Haplo-diploid life cycles, mostly
autotrophic, retaining embryo within female sex organ on parent plant.
5. Kingdom Animalia [1,000,000 species]: Multicellular animals, without cell
walls and without photosynthetic pigments, forming diploid blastula.
1. The five-kingdom system of classification for living organisms,
including the prokaryotic Monera and the eukaryotic Protista, Fungi,
Plantae and Animalia is complicated by the discovery of archaebacteria.
The prokaryotic Monera include three major divisions: The regular
bacteria or eubacteria; the cyanobacteria (also called blue-green algae);
and the archaebacteria. Lipids of archaebacterial cell membranes differ
considerably from those of both prokaryotic and eukaryotic cells, as do
the composition of their cell walls and the sequence of their ribosomal
RNA subunits. In addition, recent studies have shown that
archaebacterial RNA polymerases resemble the eukaryotic enzymes, not
the eubacterial RNA polymerase.
Archaebacteria also have introns in some genes, an advanced eukaryotic
characteristic that was previously unknown among prokaryotes. In
eukaryotic cells, the initial messenger RNA (M-RNA) transcribed from
the DNA (gene) is modified (shortened) before it leaves the nucleus.
Sections of the M-RNA strand called introns are removed, and the
remaining portions called exons are spliced together to form a shortened
(edited) strand of mature M-RNA that leaves the nucleus and travels to
the ribosome for translation into protein. This process is known as "gene
editing." Some authorities hypothesize that eukaryotic organisms may
have evolved from ancient archaebacteria (archae = ancient) rather than
from the common and cosmopolitan eubacteria. The archaebacteria could
have flourished more than 3 billion years ago under conditions
previously thought to be uninhabitable to all known life forms.
Although many conservative references place the archaebacteria in a
separate division within the kingdom Monera, most authorities now
recognize them as a 6th kingdom--The kingdom Archaebacteria. In fact,
data from DNA and RNA comparisons indicate that archaebacteria are so
different that they should not even be classified with bacteria.
Systematists have devised a classification level higher than a kingdom,
called a domain or "superkingdom," to accomodate t accomodate the
archaebacteria he archaebacteria. These remarkable organisms are now
placed in the domain Archaea. Other prokaryotes, including eubacteria
and cyanobacteria, are placed in the domain Bacteria. All the kingdoms
of eukaryotes, including Protista (Protoctista), Fungi, Plantae and
Animalia, are placed in the domain Eukarya. The large molecular
differences between the majority of prokaryotes in the kingdom Monera
and the archaebacteria warrants a separation based on categories above
the level of kingdom. In other words, the differences between the true
bacteria and archaebacteria are more significant than the differences
between kingdoms of eukaryotes.
Guillaume Lecointre and Hervé Le Guyader (2006) have published a
remarkable book entitled The Tree of Life: A Phylogenetic
Classification. The book includes the three major domains which are in
turn subdivided into numerous branches (clades). An oversimplified 3domain system of classification is shown in the following table. The
number of subdivisions listed by G. Lecointre and H.L. Guyader for each
domain are shown in parentheses.
Three Domains (Superkingdoms) Of Living Organisms
I. Bacteria (19): Most of the Known Prokaryotes
Kingdom (s): Not Available at This Time
Division (Phylum) Proteobacteria: N-Fixing Bacteria
Division (Phylum) Cyanobacteria: Blue-Green Bacteria
Division (Phylum) Eubacteria: True Gram Posive Bacteria
Division (Phylum) Spirochetes: Spiral Bacteria
Division (Phylum) Chlamydiae: Intracellular Parasites
II. Archaea (16): Prokaryotes of Extreme Environments
Kingdom Crenarchaeota: Thermophiles
Kingdom Euryarchaeota: Methanogens & Halophiles
Kingdom Korarchaeota: Some Hot Springs Microbes
III. Eukarya (35): Eukaryotic Cells
Kingdom Protista (Protoctista)
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
See Archaebacteria: Life On Mars?
2. The kingdom Protista includes a diverse array of organisms, from
minute flagellated cells to macroscopic kelp. The smallest microscopic
organisms are termed protists, consequently some biologists prefer to call
this kingdom the Protoctista rather than Protista. All members of this vast
phylum have nucleated cells and live in aquatic habitats (freshwater and
marine). According to Lynn Margulis, K.V. Schwartz and M. Dolan
(1994), the cells of all Protoctista originally formed by bacterial
symbioses (symbiogenesis).
Symbiogenesis: Genetic Mergers Forming New Species
Members of the kingdom Protoctista are not animals, which develop
from an embryo called a blastula; they are not plants, which develop
from an embryo that is not a blastula but is retained in the mother's
tissue; they are not fungi which develop from spores and lack cilia and
flagella (called undulipodia) at all stages of development; they are not
monerans, which have prokaryotic cells.
The Structure Of 9 + 2 Cilia & Flagella (Undulipodia)
A Simple Comparison Between Animal & Plant Cells
Fossil protoctists, with thick-walled resting stages or cysts, can be
extracted from shale treated with hydroflouric acid. One of the richest
sources of bizarre fossil protoctists was discovered in southern Australia
during the late 1950s. Known as the Ediacaran biota, these deposits date
back 600 million years ago. Some of these ancient protoctists may have
been ancestral to certain animal and plant phyla. In fact, some flattened
protoctists discovered in the Ediacaran biota had characteristics
resembling lichens. [Lichens are organisms resulting from genetic
mergers betweeen protists and fungi.] All the Ediacaran biota became
extinct by about 530 million years ago and were replaced be shelled
Cambrian animals.
The Evolution Of Land Plants From Ediacaran Life
Some general biology textbook authors place the microscopic, unicellular
green algae (Division Chlorophyta) in the Kingdom Protista, and place
the larger, multicellular (macroscopic) green algae (Division
Chlorophyta) in the Kingdom Plantae. They also place the macroscopic,
multicellular brown algae (Division Phaeophyta) and red algae (Division
Rhodophyta) in the Kingdom Plantae. In fact, some authors place all of
the algae divisions in the Kingdom Plantae. Although the Kingdom
Protista includes mostly unicellular organisms, the WAYNE'S WORD
staff feels that these algal divisions belong in the Kingdom Protista
(Protoctista) rather than the Kingdom Plantae.
See The Amazing Algae Causing Pink Snow
See The Bacteria Causing Pink Salt Lakes
3. Some members of the Kingdom Fungi (in the fungal classes
Ascomycetes and Basidiomycetes) are associated with algal cells of the
Kingdom Protista (in the algal division Chlorophtya) and/or prokaryotic
cyanobacteria of the Kingdom Monera. This complex symbiotic,
mutualistic relationship is called lichen. Lichens are essentially
lichenized fungi containing unicellular monerans and/or protists.
See The Amazing Kingdom of Fungi
See Desert Varnish and Lichen Crust
4. There are approximately 1.6 million species of living organisms on
earth. This number may be much higher because new species are
continually being discovered each day, particularly insects and
nematodes in remote tropical regions. However, at the present rate of
destruction, most of the virgin tropical rain forest will be annihilated by
the end of the 20th century, so many species will never be known to
humans. It is estimated that 99 percent of all the species that have ever
lived on earth were already extinct before humans ever walked on this
planet. Although humans have a phenomenal impact on the ecology of
earth, they are relative newcomers on this great planet. It is estimated
that the earth is over 4.5 billion years old, and ancient life forms (such as
the cyanobacteria) appeared about 2-3 billion years ago. If the geologic
history of the earth is compared to a 24-hour time scale, the first
multicellular organisms do not appear until just after 8:00 P.M. and
humans are not on the scene until less than a minute before midnight.
5. There are more than one million species of animals (Kingdom
Animalia), more than all the other kingdoms combined. More than half
of all animal species are insects (800,000 species), and beetles (300,000
species) comprise the largest order of insects (one fifth of all species-using a total of 1.5 million). In fact, if all the species of plants and
animals on earth were lined up at random, every 5th species would be a
beetle.
See The Wild And Wonderful World Of Beetles
6. Viruses: Viruses do not belong to the above 5 kingdoms of life. They
are much smaller and much less complex than cells. They are
macromolecular units composed of DNA or RNA surrounded by an outer
protein shell. They have no membrane-bound organelles, no ribosomes
(organelle site of protein synthesis), no cytoplasm (living contents of a
cell), and no source of energy production of their own. They do not
exhibit autopoiesis--i.e. they do not have the self-maintenance metabolic
reactions of living systems. Viruses lack cellular respiration, ATPproduction, gas exchange, etc. However, they do reproduce, but at the
expense of the host cell. Like obligate parasites, they are only capable of
reproduction within living cells. In a sense, viruses hijack the host cell
and force it to produce more viruses through DNA replication and
protein synthesis. Outside of their host cells, viruses can survive as
minute macromolecular particles. Viruses may attack animals and plants.
Infectious human viruses can be dispersed though the air (airborne
viruses) or body fluids (HIV virus). Epidemic viruses (such as HIV) that
are passed from person to person via sexual conjugation are remarkably
similar to computer viruses. Unfortunately in humans there is no resident
antivirus program to alert you of a potential infection, or to quickly scan
your body and delete the invader once it has entered your system.
Humans must rely on their amazing antibody and cell-mediated immune
response, one of the most complex and remarkable achievements in the
evolution of living systems.
The discovery of a virus called "mimivirus" in 1992 complicates
the placement of viruses in the overall classification scheme for
living organisms. Whether mimivirus should be placed in an
existing domain (superkingdom), or in its own domain, remains
to be seen. Prior to this discovery, viruses were generally
considered nonliving until they hijack a living cell. Officially, this
virus got its name because it mimics bacteria in size and
complexity. Mimivirus was found inside an amoeba within a
cooling tower in Bradford, UK. [The cooling tower was being
investigated as the source of an influenza outbreak.] Mimivirus
is the largest known virus, about 0.8 micrometers (800
nanometers) across. In fact it is larger than the bacterium
causing gonorrhea. The virus genome contains 1.2 million bases,
more than many bacteria. The bases make up 1,260 genes,
which makes it as complex as some bacteria. Most viruses use
either DNA or RNA to carry their genetic information, but
mimivirus has both of these nucleic acids. In addition, mimivirus
can make about 150 of its own proteins, and can even repair its
own DNA if it gets damaged. Normal viruses are not capable of
protein synthesis or DNA repair on their own, they must rely on
the organelles of their host cells for these activities.
For more information, see D. Raoult, et al. "The 1.2-Mb Genome
Sequence of Mimivirus." Science Published On-line, DOI:
10.1126/Science.1101485 (2004); B. La Scola et al. "A Giant
Virus in Amoebae." Science 299 (5615): 2033 (2003).
More Information About the Mimivirus
See The WAYNE'S WORD Virus Article
T
he most morphologically and biochemically diverse, non-animal kingdom
is the Plantae or Plant Kingdom. It is subdivided into the following 10 phyla
or divisions. Note: These names vary considerably, depending on which
botany reference you are using.
Categories Within The Kingdom Plantae

Nonvascular Plants: No water-conducting cells (xylem).
1. Division Bryophyta (mosses and liverworts).

Vascular plants: Xylem tissue, true roots, stems & leaves.
[The following divisions are often placed in Division Tracheophyta]
Pteridophytes: Spores but no seeds
2. Division Psilophyta (Psilotum or whisk fern.
3. Division Lycophyta (club mosses).
4. Division Sphenophyta (horsetails).
5. Division Pterophyta (ferns).
Spermatophytes: Seed Plants

Gymnosperms--Naked Seeds
6. Division Cycadophyta (cycads).
7. Division Ginkgophyta (maidenhair tree).
8. Division Gnetophyta (mormon tea & Welwitschia).
9. Division Coniferophyta (Pinophyta: conifers).

Angiosperms--Seeds Enclosed In A Fruit
10. Division Anthophyta (flowering plants)
E
ach of the plant divisions in the above table are further subdivided into
successively smaller and smaller subcategories. The complete hierarchal
breakdown is Kingdom-Phylum (Division)-Class-Order-Family-GenusSpecies. To remember this sequence, the following mnemonic device is often
helpful:
King--Phillip--Came--Over--For--Good--Soup
A Biological and Military (Army) Organizational Hierarchy Compared:
Biological Organization
T
Military Organization
Kingdom (one or more phyla)
Brigade (two or more regiments)
Phylum (one or more classes)
Regiment (two or more battalions)
Class (one or more orders)
Battalion (two or more companies)
Order (one or more families)
Company (two or more platoons)
Family (one or more genera)
Platoon (two or more squads)
Genus (one or more species)
Squad (a group of 12 soldiers)
Species (a distinct kind or unit)
Soldier (a distinct kind or unit)
he following table compares the complete taxonomic hierarchy of a
marine lichen of the rocky Pacific coast Verrucaria maura with the minute
aquatic flowering plant Wolffia borealis:
T
Kingdom
Fungi
Plantae
Phylum
Eumycota
Tracheophyta
Class
Ascomycetes
Angiospermae
Order
Pyrenulales
Arales
Family
Verrucariaceae
Lemnaceae
Genus
Verrucaria
Wolffia
Species
maura
borealis
he plant kingdom includes nonvascular and vascular plants. Nonvascular
plants lack a water-conducting system of tubular cells (called xylem tissue),
and do not have true roots, stems and leaves. Like algae and fungi, the plant
body of some nonvascular plants is often called a thallus. Nonvascular plants
are all placed in the Division Bryophyta, including the mosses and
liverworts. The vast majority of the plant kingdom are vascular, with tubular,
water-conducting cells called xylem tissue. Like a microscopic pipeline
system, they are arranged end-to-end from the roots to the leaves. Unlike
nonvascular plants, they have true roots, stems and leaves. Some references
place all the vascular plants in a separate phylum or division called the
Tracheophyta. Most botanists now subdivide vascular plants into 9 divisions.
More primitive vascular plants that reproduce by spores, but without seeds,
are called pteridophytes, and include the 4 divisions Psilophyta (whisk ferns),
Lycophyta (club mosses), Sphenophyta (horsetails), and Pterophyta (ferns).
Seed-bearing vascular plants are called spermatophytes and include the
primitive gymnosperms (with immature seeds or ovules naked and exposed
directly to pollen) and the more advanced angiosperms (with ovules enclosed
in an ovary that ripens into a fruit). Gymnosperms include the 4 divisions
Cycadophyta (cycads), Ginkgophyta (maidenhair tree), Gnetophyta
(mormon tea & the bizarre South African Welwitschia), and the
Coniferophyta (conifers). The angiosperms are placed in the single division
Anthophyta which includes all the flowering plants and 90 percent of all the
plant kingdom.
See The Amazing Welwitschia Plant
See Diversity In Flowering Plants
Twenty of the more than 100 species of Pinus on earth. All of these
pines are native to the state of California, USA. 1. Monterey Pine (P.
radiata), 2. Bishop Pine (P. muricata), 3. Santa Cruz Island Pine (P.
remorata), 4. Whitebark Pine (P. albicaulis), 5. Limber Pine (P. flexilis),
6. Beach Pine (P. contorta), 7. Lodgepole Pine (P. murrayana), 8.
Western White Pine (P. monticola), 9. Knobcone Pine (P. attenuata),
10. Bristlecone Pine (P. longaeva), 11. Foxtail Pine (P. balfouriana), 12.
Four-Leaf Pinyon (P. quadrifolia), 13. Two-Leaf Pinyon (P. edulis), 14.
One-Leaf Pinyon (P. monophylla), 15. Ponderosa Pine (P. ponderosa),
16. Coulter Pine (P. coulteri), 17. Digger Pine (P. sabiniana), 18. Torrey
Pine (P. torreyana), 19. Jeffrey Pine (P. jeffreyi), 20. Sugar Pine (P.
lambertiana).
Note: In the Jepson Flora of California (1993), Pinus
remorata is now considered a synonym of P.
muricata. Another species (left image) called the
Washoe Pine (P. washoensis), with cones similar to a
miniature Jeffrey Pine, is now recognized for
California. In addition, the Beach and Lodgepole Pines
are now recognized as subspecies of P. contorta,
rather than separate species.
According to R.M. Lanner (Conifers of California, 1999), there may be
other significant changes in the pines of California. Allozyme studies in
two-leaf pinyons (Pinus edulis) of the New York Mountains indicate that
these populations are biochemically (and genetically) consistent with
nearby one-leaf pinyon (Pinus monophylla), and that P. edulis may not
occur in California. The unusual New York Mountains population
appears to be a 2-needle variant of P. monophylla. The four-leaf or
Parry pinyon of San Diego County (P. quadrifolia) may be a hybrid
between P. monophylla and Sierra Juárez pinyon (P. juarezensis) of
northern Baja California. According to Lanner, the latter species has five
needles per fascicle and occurs in San Diego County. The hybrid
hypothesis might explain the perplexing variation in needle number for
P. quadrifolia, with clusters of three, four and five.
See A Giant Coulter Pine Cone
Foxtail pines (Pinus balfouriana) on the 11,000 ft (3353 m) slopes of
Alta Peak. The 13,000 ft. (3962 m) crest of the Great Western Divide of
the Sierra Nevada can be seen in the distance.
Selection & Genetic Drift In California Cypress
M
illions of years ago, cypress woodlands containing one or more ancestral
species of the cone-bearing genus Cupressus once dominated vast areas of
California. During the past 20 million years, as mountains were uplifted and
the climate became increasingly more arid, most of these extensive cypress
woodlands vanished from the landscape. In some areas, the cypress were
probably unable to compete with more drought resistant, aggressive species,
such as impenetrable chaparral shrubs and desert scrub. Although cypress are
fire-adapted with serotinous seed cones that open after a fire, they are
vulnerable if the fire interval occurs too frequently, before the trees are old
enough to produce a sufficient cone crop. Chaparral shrubs quickly resprout
after a fast-moving brush fire from well-established subterranean lignotubers.
This may explain why some cypress groves occur in very rocky, sterile sites
with poor soils where the chaparral shrubs can't compete as well.
See Article About Brush Fires In California
T
oday this fascinating genus is represented by 10 species (or 8 species and
2 subspecies), confined to isolated groves scattered throughout the coastal and
inland mountains, from the Mexican border to Oregon. Because some of these
populations became isolated into "arboreal islands," gradual genetic changes
over millions of years resulted in the present-day species and subspecies. This
is somewhat analogous to the evolution of Darwin's finches on the Galapagos
Islands. It is quite likely that natural selection played a role in cypress
speciation. Cypress of arid inland mountains and valleys (such as Piute
cypress, Macnab cypress, Cuyamaca cypress, and Arizona cypress) have
glandular (resinous) foliage and are more drought resistant. Coastal species
(such as Monterey cypress, Gowen cypress, Santa Cruz cypress and
Mendocino cypress) are generally nonglandular without resin glands on the
leaf surfaces. Some phenotypic variability, particularly between different
isolated groves of the same species may be due (in part) to genetic drift. These
differences include slight variations in foliage, bark characteristics
(exfoliating vs. persistent), and the general shape of seed cones. These
differences attributed to genetic drift are analogous to racial differences in
people, such as different blood type percentages and facial characteristics.
T
he relatively short period of isolation for Cupressus (cypress) species
may be one of the reasons taxonomists disagree on the total number of species
native to North America. In 1948, Carl B. Wolf published his "Taxonomic and
Distributional Studies of the New World Cypresses" (El Aliso 1: 1-250). Dr.
Wolf listed a total of 15 species, one in Baja California, one on Guadalupe
Island off the coast of Baja California, one in Mexico and Central America,
two in Arizona, and 10 in California. In 1953, the number of U.S. species was
reduced to six by Dr. Elbert Little, Jr. in his Check List of Native and
Naturalized Trees of the United States (USDA Agriculture Handbook No.
41). These numbers have fluctuated greatly in subsequent publications. In
addition, the nursery trade has added several cultivated varieties, including at
least four different cultivars for the Arizona cypress.
N
ew evidence from DNA sequencing has further complicated the number
of cypress species, including the transfer of other conifer genera into the
genus Cupressus. For example, the Jepson Manual of California Plants
lists ten species; however, two of these C. nootkatensis (Alaska cedar) and C.
lawsoniana (Port Orford cedar) were formerly placed in the genus
Chamaecyparis. It is possible that some of the isolated species of Cupressus
in California and Arizona have not been isolated long enough to warrant the
status of a species. In fact, this is why most modern floras have consolidated
four species into subspecies of the Arizona cypress (C. arizonica). These
species have been isolated long enough for genetic drift to occur, but perhaps
not long enough for the development of distinct species populations.
Left: Seed cones of cypress (Cupressus) from groves in southern
California. A. Tecate cypress (C. forbesii), B. Sargent cypress (C.
sargentii), C. Piute cypress (C. nevadensis) [Syn. C. arizonica ssp.
nevadensis], D. Cuyamaca cypress (C. stephensonii) [Syn. C. arizonica
spp. stephensonii], E. Smooth-bark Arizona cypress (C. glabra) [Syn. C.
arizonica ssp. glabra], F. Rough-bark Arizona cypress (C. arizonica)
[Syn. C. arizonica ssp. arizonica]. Right: Seed cones of cypress from
groves in central and northern California. G. Monterey cypress (C.
macrocarpa), H. Gowen cypress (C. goveniana) [Syn. C. goveniana ssp.
goveniana], I. Santa Cruz cypress (C. abramsiana), J. Sargent cypress
(C. sargentii), K. Mendocino cypress (C. pygmaea) [Syn. C. goveniana
ssp. pigmaea], L. Macnab cypress (C. macnabiana), M. Modoc cypress
(C. bakeri).
Male (pollen) cones of the Piute cypress (Cupressus nevadensis) [syn.
C. arizonica ssp. nevadensis). Each scalelike leaf bears a dorsal gland
that exudes a resin droplet (red arrow). Interior cypress species such
as this one typically have glaucous, resinous foliage, presumably an
adaptation to dry, arid habitats.
A. Foliage and pollen cones of the Smooth-bark Arizona cypress
(Cupressus glabra) [Syn. C. arizonica ssp. glabra]. B. Foliage of the
Tecate cypress (C. forbesii). The scalelike leaves of Arizona cypress are
glaucous and very glandular (sticky). The scalelike leaves of Tecate
cypress are green and without dorsal resin glands.
Left: Monterey cypress (Cupressus macrocarpa) in Point Lobos State
Park on the coast of central California. Right: Grove of Piute cypress (C.
nevadensis) in the Piute Mountains, with Lake Isabella and the snowcovered Sierra Nevada in the distance. The Piute cypress are more
drought resistant, with gray (glaucous), glandular (resinous) foliage
similar to the Arizona cypress. In fact, some botanists now consider
the Piute cypress to be a subspecies of the Arizona cypress and have
named it C. arizonica ssp. nevadensis.
A grove of Sargent cypress (Cupressus sargentii) in the San Rafael
Mountains of Santa Barbara County, California. This species typically
grows on outcrops of serpentine in the Coast Ranges of central and
northern California. Serpentine is a shiny rock with a waxy luster and
feel. It varies in color from creamy white and shades of green to black.
In California, many species of rare and endangered plants are endemic
to serpentine outcrops. Genetic drift has undoubtedly occured in
isolated cypress groves such as this one, which are often referred to as
"arboreal islands."
Other Members Of The Division Coniferophyta
Podocarpus gracilior, a member of the Podocarpaceae native to
eastern Africa. Although it is sometimes called "fern pine" it does not
belong to the genus (Pinus); however, like pines and other conebearing species, it does belong to the Division Coniferophyta. Minute
female cones are composed of 2-4 reduced scales, but usually only
one scale bears an ovule that matures into a seed. There is little
resemblance to a cone in the mature seed. The seed has a hard coat
surrounded by a fleshy outer layer (aril). The drupelike seed often sits
on a fleshy red or purple base or cone axis that is called an aril in some
references. The seeds are similar to the California nutmeg (Torreya
californica) and Pacific yew (Taxus brevifolia), members of the closelyrelated Yew Family (Taxaceae). In the latter species, the naked seed
sits partially exposed in a red, cup-shaped aril. Podocarpus seeds are
often referred to as fleshy fruits called drupes, but this is incorrect
because drupes develop from the ovaries of flowering plants. Another
group of conifers with fleshy seed-bearing structures are the junipers
(Juniperus) in the Cypress Family (Cupressaceae). Junipers actually
produce small cones with fleshy, fused scales bearing one-several
seeds. Podocarpus is a dioecious species, with separate male and
female trees in the population. Podocarpus has an ancient lineage
dating back to distant relatives that lived during the Jurassic Period
170 million years ago.
California nutmeg (Torreya californica), a member of the Division
Coniferophyta, Order Taxales, Family Taxaceae. Like Podocarpus, the
"naked" seed is enclosed in a fleshy, outer layer (called an aril) which
superficially resembles a one-seeded fruit of an angiosperm. The name
"nutmeg" is derived from its superficial resemblance to the fruit of the
true nutmeg (Myristica fragrans).
Pacific yew (Taxus brevifolia), another member of the Division
Coniferophyta, Order Taxales, Family Taxaceae that occurs in northern
California, Oregon and Washington. Unlike the California nutmeg, the
naked seed is not completely enclosed by the fleshy aril. Instead, the
seed sits in a cup-shaped aril. Since this species is native to regions of
the Pacific northwestern United States containing the timber tree
Douglas fir (Pseudotsuga menziesii), it was once considered a weedy
species when areas of the forest were logged. Luckily, the Pacific yew
still survives because it is now considered to be an exceedingly
valuable species. An extract from the bark (and needles) called taxol
has been found to be a very effective treatment for ovarian and breast
cancers. It is very important to preserve natural, old growth forests
with a diversity of species, some of which may prove to be valuable
medicines for the treatment of diseases.
Santa Lucia Fir (Abies bracteata)
The Santa Lucia or bristlecone fir (Abies bracteata) has a tall, slender,
steeple-like crown. Seed cones are produced near the top of the
slender spire, and they are some of the most unusual cones of all
cone-bearing trees on earth. Long, spine-like bracts extend outwardly
from between the cone scales, and resemble the antennae of a space
satellite. This uncommon and remarkable fir tree is endemic to steep,
rocky slopes in the Santa Lucia Range of California's Coast Ranges.
Santa Lucia fir (Abies bracteata), a remarkable California endemic.
See Conifers Of The Araucaria Family
U
sing fossil evidence and computerized cladistic analyses, it is generally
concluded that evolution in the plant kingdom proceeded from nonvascular,
spore-bearing ancestors to vascular, seed-bearing, flowering plants, as more
and more advanced morphological and biochemical traits gradually appeared
along the geologic time scale. This is somewhat analogous to the evolution of
Microsoft; however, unlike Microsoft, the phenomenal success of flowering
plants is based on natural selection rather than timely, strategic decisions by
brilliant top level executives such as Bill Gates.
See Evolution of Microsoft vs. Natural Selection of Antlions
See Ancient Seed Plants "Living Fossils" At Palomar College
Ancient Plants That Lived When Dinosaurs Roamed The Earth
See The Demise of Dinosaurs and The Rise of Flowering Plants
References
1. Armstrong, W.P. 1978. "Southern California's Vanishing
Cypresses." Fremontia 6 (2): 24-29.
2. Armstrong, W.P. 1977. "The Close-Cone Pines and Cypresses"
(Chapter 9, pp. 295-358). In: Terrestrial Vegetation of California,
John Wiley & Sons.
3. Hickman, J.C. (Editor). 1993. The Jepson Manual: Higher Plants of
California. University of California Press, Berkeley.
4. Lecointre, G. and H.L. Guyader. [Illustrated by D. Visset &
Translated by K. McCoy.] 2006. The Tree of Life: A Phylogenetic
Classification. Harvard University Press, Cambridge,
Massachusetts.
5. Margulis, L., K.V. Schwartz, and M. Dolan. 1994. The Illustrated
Five Kingdoms: A Guide To The Diversity Of Life On Earth.
HarperCollins College Publishers, New York.
Return To The Gee-Whiz Trivia Home Page
Return To The WAYNE'S WORD Home Page
Return To The NOTEWORTHY PLANTS Menu
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Source: Armstrong (1999) Major Divisions Of Life
http://waynesword.palomar.edu/trmar99.htm 29-12-2010
Major Divisions Of Life
Generally Included In Botany Courses
1.
2.
3.
4.
5.
Kingdom Monera
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
The Major Divisions Of Life:
Thallophytes
Embryophytes
Bryophytes
Tracheophytes
Pteridophytes
Spermatophytes
Select A Division
Note: An alternations of generations occurs in members of the algae, fungi and plant
kingdoms. For example, the edible red alga called nori is actually the haploid
gametophyte phase that alternates with a minute, filamentous sporophyte form that
lives inside sea shells. The diploid sporophyte fern is the typical, spore-bearing plant that
we see in cultivated flower beds and in moist areas throughout North America. The
haploid fern gametophyte is a small, seldom-seen, thallus plant about the size of your
smallest fingernail. It grows on the moist ground beneath sporophyte fern populations in
areas with sufficient rainfall. Even flowering plants have a conspicuous sporophyte
generation that alternates with a microscopic gametophyte phase within the ovule. The
gametophye phase is reduced to a 7-celled, egg-bearing embryo sac within the ovule,
and a germinated pollen grain and sperm-bearing pollen tube.
I. Thallophytes: Plant body called a thallus, without true roots, stems
or leaves; zygote not developing into multicellular embryo within the
female sex organ; typically nonvascular without a water-conducting
system of cells. [I.e. without xylem tissue.]
1. Kingdom Monera:
Note: Kingsley R. Stern (Introductory Plant Biology, 8th Edition, 2000) has
replaced the Kingdom Monera with two kingdoms: the Eubacteria and the
Archaebacteria. Kingdom Eubacteria includes the Division Eubacteriophyta
(True Bacteria) and the Division Cyanophyta (Formerly Blue-Green Algae).
Tree Of Life: The Phylogeny Of Living Organisms
1. Division Eubacteriophyta (True Bacteria or Eubacteria)
Prokaryotic, unicellular organisms; three major types or forms, including
spherical coccus, rod-shaped bacillus and spiral-shaped spirillum forms; many
pathogenic as well as beneficial species; studied in bacteriology and
microbiology courses; grow practically everywhere, including your mouth and
digestive tract, the root nodules of legumes and the sun-baked boulders of arid
deserts; the latter bacteria are responsible for microscopic layers of iron and
manganese oxide on boulders known as desert varnish.
Yellow sweet clover (Melilotus indicus), a member of the pea family
(Fabaceae). The roots of this legume contain swollen nodules (red arrow)
containing nitrogen-fixing bacteria of the genus Rhizobium or
Bradyrhizobium in the bacteria family Rhizobiaceae.
Nitrogen fixation is a remarkable prokaryotic skill in which inert atmospheric
nitrogen gas is converted into ammonia. Through another bacterial process
called nitrification, the ammonia is converted into nitrites and nitrates, thereby
making the vital element nitrogen readily available to the roots of higher
plants. Since this process commonly occurs in the root nodules of legumes,
farmers often rotate their crops with leguminous species (such as alfalfa and
clover). The economic importance of legumes and root nodules is astonishing.
For example, the average annual crop of clover seed in Ohio (250,000
bushels) will plant approximately 3 million acres in clover. This acreage
would yield about 4.5 million tons of hay (worth about $90 million). Because
of nitrogen fixation in the root nodules of clover, about 273 million pounds of
nitrogen is added to the soil (worth about $50 million annually). Nitrogen
fixation is also accomplished by a number of species of microscopic
cyanobacteria, some of which live symbiotically in nonleguminous plants,
including the leaves of water fern (Azolla) and the roots of cycads. The actual
sites of nitrogen fixation in the cyanobacteria are special cells called
heterocysts. The roots of alder trees (Alnus), wax myrtle (Myrica) and
California lilac (Ceanothus) contain nitrogen-fixing actinomycetes rather
than eubacteria. Nodules of the actinomycete Frankia on alder roots greatly
resemble the Rhizobium nodules of legumes.
Actinomycetes include a large group of filamentous, fungus-like soil bacteria.
They form long, threadlike, branched filaments that resemble gray spiderwebs
throughout compost piles. In fact, the characteristic earthy smell of compost
and recently overturned rotten logs in a forest is caused by thriving
populations of actinomycetes. Electron microscopy and other studies have
shown unequivocally that these organisms are bacteria and not fungi. Some
authors refer to actinomycetes as actinobacteria and place them in their own
phylum.
Two Species Of California Lilac (Ceanothus)
Nitrogen Fixation and Nitrification Defined
Cyanobacteria In The Water Fern (Azolla)
Cyanobacteria In The Roots Of Cycads
Note: Although most of the bacteria in this division Eubacteriophyta are
heterotrophic, there are some autotrophic species which produce ATP and
glucose by oxidizing chemicals in their environment (chemosynthesis) or by
utilizing light energy in thylakoid membranes (photosynthesis). Some of the
photosynthetic species have pigments similar to chlorophyll a in higher plants,
but they do not produce oxygen as a by-product of photosynthesis. The
photosynthetic Eubacteriophyta include purple sulphur bacteria, purple
nonsulphur bacteria, green sulphur bacteria and prochlorobacteria. The
prochlorobacteria are quite distinct from other members of the
Eubacteriophyta because they possess both chlorophylls a and b of higher
plants. The prochlorobacteria also produce oxygen like the Division
Cyanophyta, but unlike the cyanobacteria they do not have phycobilin
accessary pigments. [It should be noted here that some biologists place the
prochlorobacteria in the Division Cyanophyta.]
The following simplified equation shows photosythesis of purple sulfur
bacteria:
CO2 + 2 H2S = CH2O + H2O + 2 S
Carbon dioxide + hydrogen sulfide react with bacteriochlorophyll and
sunlight to form carbohydrate (such as glucose) + water + sulphur.
Compare the above equation with photosynthesis in green plants:
CO2 + 2 H2O = CH2O + H2O + O2
Carbon dioxide + water react in the presence of chlorophyll
and sunlight to form carbohydrate + water + oxygen.
Read About Phycobilin Pigments
See Desert Varnish On Rocks
Pathogenic Bacteria
There are numerous pathogenic forms of bacteria that live parasitically inside
a living host. They are spread by airborne spores, contaminated foods and
body fluids. The sciences of bacteriology and microbiology are concerned
with the study of these organisms. The following images show three serious
infectious bacteria, anthrax, gonorrhea and syphilis. Anthrax (Bacillus
anthacis) is one of the microorganisms used in biological warfare because
strains have been developed that are extremely infectious through the skin and
through inhalation. In addition, it forms highly resistant spores that can
survive for long periods. Approximately one teaspoon or two grams of anthrax
may contain up to 20 billion spores. With an average infection rate of 10,000
spores per person, this is theoretically enough spores to infect 2 million people
with inhalation anthrax.
Gonorrhea and syphilis are venereal diseases that are spread through sexual
contact. Gonorrhea is caused by the bacterium Neisseria gonorrhoeae.
Although rarely fatal, gonorrhea is a potentially serious infection of the
urogenital system. A sample of pus from the infection can be placed on a
microscope slide and stained to reveal masses of white blood cells and minute
diplococcus bacteria (resembling minute paired dots). Syphilis is caused by
the spiral-shaped (spirochaete) bacterium Treponema pallidum. The disease
has three main stages which are typically separated by latent (dormant)
periods during which the infected person may think the disease has vanished.
In the initial stage, an ulcerated sore (called a chancre) appears in the genital
area. In the secondary stage, a rash appears all over the body, even on the
palms of the hands and soles of the feet. During the tertiary stage, the bacteria
invade other organs of the body, such as the heart, liver and nervous system,
the effects of which are devastating to the host. Long term effects of tertiary
syphilis may include blindness, difficulty walking, insanity and eventually
death. If detected early, both gonorrhea and syphilis can be treated with
antibiotics; however, as with other bacteria, new resistant strains are
constantly developing.
Six other sexually transmitted diseases in humans are: (1) Chlamydia caused
by the bacterium Chlamydia trachomatis; (2) Vaginitis caused by the
flagellated protozoan Trichomonas vaginalis. Vaginitis may also be caused
by increased populations of yeast fungus (Candida albicans) that comprise
the vaginal flora; (3) Hepatitis B and C caused by hepatitis viral strains B and
C. Hepatitis A is generally acquired from contaminated food but may be
transmitted sexually; (4) Genital Herpes caused by the herpes simplex virus
type 2. Herpes simplex virus type 1 causes cold sores and fever blisters; (5)
Genital Warts caused by the human papillomaviruses (HPVs). Genital warts
are associated with cancer of the cervix and other urogenital tumors; and (6)
AIDS (Acquired Immunodeficiency Syndrome) caused by the human
immunodeficiency virus (HIV).
Left: Highly magnified view (2000 X) of human pus showing white blood
cells (called neutrophils) with deeply-lobed purple nuclei. The minute
paired dots (red arrow) are diplococcus gonorrhea bacteria. Each dot
(coccus bacterium) is only about 0.5 micrometers in diameter. Some of
the neutrophils have ingested the bacteria through phagocytosis. Right: A
culture of rod-shaped anthrax bacteria. Some of the bacteria have divided
by fission (red arrow). [Both images came from old (circa 1960) prepared
microscope slides enhanced with PhotoShop and Paint Shop Pro by W.P.
Armstrong.]
Highly magnified view (2000 X) of a human liver infested with spiral,
threadlike syphilis bacteria (Treponema pallidum). This diseased liver
tissue came from an autopsy on a person in the fatal tertiary stages of
syphilis. [Image from an old (circa 1960) prepared microscope slide
enhanced with Adobe PhotoShop by W.P. Armstrong.]
2. Division Cyanophyta (Blue-Green Bacteria)
Prokaryotic filaments or gelatinous colonies of photosynthetic cells; produce
the blue phycocyanin and red phycoerythrin phycobilin pigments; not always
blue-green as in the coloration of the Red Sea by Trichodesmium
erythraeum; referred to as "blue-green algae" in some references;
cyanobacteria live in some of the most bizarre places on earth, including the
trunks of trees and the roots of cycads; they also form a thin, black layer on
the limestone blocks of Maya pyramids in Central America; cyanobacteria
include some of the oldest life forms on earth and produce stromatolite fossils
in limestone over 2 billion years old.
Note: The photosynthetic cyanobacteria contain chlorophyll a in their
thylakoid membranes. Chlorophyll a is also present in thylakoid membranes
within chloroplasts of higher plants. These bacteria also produce oxygen as a
by-product of photosynthesis. In fact, a photosynthetic cell from a
cyanobacterium is reminescent of a chloroplast, and some biologists believe
that chloroplasts may have evolved from photosynthetic bacterial cells. This
tentative explanation for the origin of chloroplasts is known as the
Endosymbiont Hypothesis. Cyanobacteria also contain blue phycocyanin and
red phycoerythrin pigments. Phycocyanin and phycoerythrin are accessary
pigments called phycobillins which are also found in the red algae (Division
Rhodophyta). Except for the prochlorobacteria, other bacteria in the Division
Eubacteriophyta capable of carrying on photosynthesis do not produce oxygen
and they do not have chlorophyll a. The prochlorobacteria have both
chlorophyll a and chlorophyll b of higher plants, but do not have the
phycobilins of the cyanobacteria. Because of their chemistry cell structure,
they are probably the best candidates for precursors of chloroplasts. These
remarkable green bacteria were discovered on marine invertebrates called sea
squirts (Phylum Chordata) by Dr. Ralph Lewin of Scripps Institute of
Oceanography in La Jolla, California.
See Phycobilin Pigments
See Cyanobacteria In Guatemala
Stromatolites: Fossil Cyanobacteria In Rock
Cyanobacteria Living Inside The Water Fern (Azolla)
Cyanobacteria Living Inside The Coralloid Roots Of Cycads
Cyanobacteria Living Inside A Crustose Pacific Northwest Lichen
3. Division Archaebacteriophyta (Archaebacteria)
Prokaryotic cells that are genetically quite distinct from the eubacteria;
include methanogens (methane-producers), extreme halophiles and extreme
thermophiles; live in some of the most extreme and inhospitable places on
earth; may also live on the surface of Mars.
Note: The halobacteria have a unique photosynthetic pigment in their
membranes but they do not produce oxygen. Like photosynthetic plants, the
halobacteria produce their own ATP; but unlike green plants, they utilize
bacteriorhodopsin instead of chlorophyll. The exact mechanism of ATP
production is complicated and beyond the scope of this article, but it involves
a "proton pump" across their cell membrane similar to the chemiosmotic
mechanism for ATP synthesis in the chloroplasts and mitochondria of
eukaryotic cells in higher organisms. Positively-charged hydrogen ions
(protons), forced to one side of the membrane, flow back through special
channels (pores) in the membrane as ATP (adenosine triphosphate) is
enzymatically produced from ADP (adenosine diphosphate) and P
(phosphate). These bacteria are especially interesting because the
chemiosmotic mechanism for generating ATP does not require an electron
transport system as in other photosynthetic bacteria and higher plants. Strains
of these amazing bacteria have also been shown to survive anaerobically
without free atmospheric oxygen while deeply embedded in thick salt crust.
Bacteriorhodopsin is remarkably similar to the light sensitive pigment
(rhodopsin) in the rod cells of human eyes which enables us to see in dim
light. Thus, when we enter a dimly lighted room, it takes about 30 minutes for
our eyes to adjust fully as the rhodopsin gradually increases in concentration.
Of course, a flash of light can instantaneously break down your rhodopsin
level, much to the chagrin of star-gazers who have become accustomed to the
darkness.
In recent years, the traditional 5-kingdom system of classification has been
challenged by authorities. Data from DNA and RNA comparisons indicate
that archaebacteria are so different that they should not even be called a type
of bacteria. Systematists have devised a classification level higher than a
kingdom, called a domain or "superkingdom," to accomodate the
archaebacteria. These remarkable organisms are now placed in the domain
Archaea. Other prokaryotes, including eubacteria and cyanobacteria, are
placed in the domain Bacteria. All the kingdoms of eukaryotes, including
Protista (Protoctista), Fungi, Plantae and Animalia, are placed in the domain
Eukarya. The large molecular differences between the majority of prokaryotes
in the kingdom Monera and the archaebacteria warrants a separation based on
categories above the level of kingdom. In other words, the differences
between the true bacteria and archaebacteria are more significant than the
differences between kingdoms of eukaryotes. The 3-domain system of
classification is shown in the following table:
Three Domains (Superkingdoms) Of Living Organisms
I. Bacteria: Most of the Known Prokaryotes
Kingdom (s): Not Available at This Time
Division (Phylum) Proteobacteria: N-Fixing Bacteria
Division (Phylum) Cyanobacteria: Blue-Green Bacteria
Division (Phylum) Eubacteria: True Gram Posive Bacteria
Division (Phylum) Spirochetes: Spiral Bacteria
Division (Phylum) Chlamydiae: Intracellular Parasites
II. Archaea: Prokaryotes of Extreme Environments
Kingdom Crenarchaeota: Thermophiles
Kingdom Euryarchaeota: Methanogens & Halophiles
Kingdom Korarchaeota: Some Hot Springs Microbes
III. Eukarya: Eukaryotic Cells
Kingdom Protista (Protoctista)
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
Archaebacteria: Possible Life Form On Mars?
Salt Lakes: Pink Color Caused By Halobacteria
2. Kingdom Protista (Protoctista):
The kingdom Protista includes a diverse array of organisms, from minute
flagellated cells to macroscopic kelp. The smallest microscopic organisms are
termed protists, consequently some biologists prefer to call this kingdom the
Protoctista rather than Protista. All members of this vast phylum have
nucleated cells and live in aquatic habitats (freshwater and marine). According
to Lynn Margulis, K.V. Schwartz and M. Dolan (1994), the cells of all
Protoctista originally formed by bacterial symbioses (symbiogenesis).
Symbiogenesis: Genetic Mergers Forming New Species
Members of the kingdom Protoctista are not animals, which develop from an
embryo called a blastula; they are not plants, which develop from an embryo
that is not a blastula but is retained in the mother's tissue; they are not fungi
which develop from spores and lack cilia and flagella (called undulipodia) at
all stages of development; they are not monerans, which have prokaryotic
cells. Fossil protoctists, with thick-walled resting stages or cysts, can be
extracted from shale treated with hydroflouric acid. One of the richest sources
of bizarre fossil protoctists was discovered in southern Australia during the
late 1950s. Known as the Ediacaran biota, these deposits date back 600
million years ago. Some of these ancient protoctists may have been ancestral
to certain animal and plant phyla. In fact, some flattened protoctists
discovered in the Ediacaran biota had characteristics resembling lichens.
[Lichens are organisms resulting from genetic mergers betweeen protists and
fungi.] All the Ediacaran biota became extinct by about 530 million years ago
and were replaced be shelled Cambrian animals.
The Evolution Of Land Plants From Ediacaran Biota
The Structure Of 9 + 2 Cilia & Flagella (Undulipodia)
A Simple Comparison Between Animal & Plant Cells
Some general biology textbook authors place the microscopic, unicellular
green algae (Division Chlorophyta) in the Kingdom Protista, and place the
larger, multicellular (macroscopic) green algae (Division Chlorophyta) in the
Kingdom Plantae. They also place the macroscopic, multicellular brown algae
(Division Phaeophyta) and red algae (Division Rhodophyta) in the Kingdom
Plantae. In fact, some authors place all of the algae divisions in the Kingdom
Plantae. Although the Kingdom Protista includes mostly unicellular
organisms, the Wayne's Word staff feels that these algal divisions belong in
the Kingdom Protista (Protoctista) rather than the Kingdom Plantae.
Autotrophic Thallophytes
1. Division Chlorophyta (Green Algae)
Many different forms including unicellular (non-motile and flagellate),
filamentous, and macroscopic (sea lettuce); common in fresh water and
marine environments; not always green in color, e.g. bright red snow algae
(Chlamydomonas nivalis) and orange Trentepohlia on trunks of Monterey
cypress; also includes extreme halophilic species (Dunaliella and
Dangeardinella) and the most common photobiont (autotrophic symbiont)
found in lichens (e.g. Trebouxia); unicellular green algae also grow inside the
hollow hairs of polar bears, giving their fur a greenish tinge; the term
zoochlorellae refer to several species of symbiotic green algae of the division
Chlorophyta; along the Pacific coast of North America, zoochlorellae produce
the pale greenish color in sea anemone tentacles.
See Photos Of Assorted Green Algae
Lichen Crust On Rocks & Desert Varnish
Pink Snow That Smells Like A Watermelon
Salt Lakes: Pink Color Caused By Halobacteria
2. Division Phaeophyta (Brown Algae)
Includes macroscopic seaweeds or kelps (e.g. Macrocystis, Pelagophycus
and Laminaria); harvested for the natural polysaccharide gums algin and
laminaran; contain the pigment fucoxanthin.
See Photos Of Brown Algae
An Unusual Use For Brown Algae
3. Division Pyrrophyta (Dinoflagellates)
Flagellated cells with conspicuous transverse groove; occur in blooms causing
red tide and bioluminescence in ocean water; a wide variety of marine
invertebrates, including sponges, jellyfish, sea anemones, corals, gastropods
and turbellarians harbor within them golden spherical cells termed
zooxanthellae; the photosynthetic activity of these symbiotic algal cells is vital
to the survival of the individual coral animals and to the entire reef ecosystem;
the zooxanthellae include several species of unicellular algae in the order
Zooxanthellales within the algal division Pyrrophyta (also spelled
Pyrrhophyta).
4. Division Chrysophyta (Diatoms)
Cells with ornamented silica valves which fit together like a microscopic Petri
dish; along with the dinoflagellates an extremely important member of the
ocean food chain and estimated to produce more than 70% of the earth's
atmospheric oxygen.
See Photos Of Diatoms
5. Division Rhodophyta (Red Algae)
Contain the red pigment phycoerythrin and able to photosynthesize in deep
waters of the euphotic zone; many beautiful macroscopic species; do not have
centrioles or flagella; some species form bulk of algal reefs.
See Photos Of Red Algae
6. Division Euglenophyta (Euglena)
No true cell wall; cells animal-like and classified as flagellate protozoan by
some zoologists; some species contain contractile vacuoles to expel water and
exhibit cell-engulfing (phagocytosis).
7. Division Charophyta (Stoneworts)
Interesting macroscopic algae with prominent sex organs; found in fresh water
ponds throughout San Diego County, California; sometimes placed in the
Division Chlorophyta along with the green algae.
See Photos Of Stoneworts
Heterotrophic Thallophytes
Note: The following two divisions Myomycota (slime molds) and Oomycota
(water molds) are now placed in the kingdom Protista (Protoctista), although
they are classified with the kingdom Fungi in older references. These
divisions all produce motile cells (including swarm cells and zoospores)
during some stage of their life cycles. Another division called Acrasiomycota
(cellular slime molds) is also placed in the Protista. True fungi typically do not
have eukaryotic 9 + 2 flagella (called undulipodia) at any stage in their life
cycles. These classification systems are constantly changing, especially with
new information from comparative DNA studies.
8. Division Myxomycota (Slime Molds)
Very unusual organisms characterized by a multinucleate mass (blob) of
protoplasm that moves in amoeboid fashion on wet logs and the forest floor;
at a certain phase in its life cycle the plasmodium forms spore-bearing fruiting
bodies; on several occasions, slime molds grown by Dr. George Zabka in the
Palomar College botany lab have actually crawled out of their culture dish.
See Photo Of A Slime Mold
9. Division Oomycota (Water Molds)
Nonseptate, coenocytic hyphae with sexual phase quite different from black
bread mold (Zygomycota); forming cottony filaments on various substrates in
water, including the gills of unfortunate fish; major nuisance when cultivating
duckweeds in containers of water; the Oomycota were once classified as fungi
because of their filamentous growth and heterotrophic mode of nutrition; their
cell wall is not composed of chitin, as in fungi, but is made up of a mixture of
cellulosic compounds and glycan; the nuclei in their filaments are diploid,
with two sets of genetic information (chromosomes), not haploid as in the
fungi.
The Following Protists Are Often Included In Zoology Courses
They Are Placed In Phyla Rather Than Divisions By Zoologists:
See Images Of Representative Protozoans
1. Phylum Sporozoa (Parasitic Protozoans): e.g. malaria
2. Phylum Ciliophora (Ciliated Protozoans): e.g. paramecia
3. Phylum Rhizopoda (Amoeboid Protozoans): e.g. amoeba
4. Phylum Zoomastigophora (Flagellate Protozoans): e.g. trypanosomes
3. Kingdom Fungi:
Some members of the Kingdom Fungi (in the fungal classes Ascomycetes and
Basidiomycetes) are associated with algal cells of the Kingdom Protista (in
the algal division Chlorophtya) and/or prokaryotic cyanobacteria of the
Kingdom Monera. This complex symbiotic, mutualistic relationship is called
lichen. Lichens are essentially lichenized fungi containing unicellular
monerans and/or protists.
See The Amazing Kingdom of Fungi
See Desert Varnish and Lichen Crust
Note: The divisions Myomycota (slime molds) and Oomycota (water molds) are now placed
in the kingdom
Protista (Protoctista), although they are still classified with the kingdom Fungi in some older
references.
1. Division Zygomycota (Coenocytic Fungi)
Coenocytic hyphae composed of multinucleate, nonseptate filaments;
produces stalked sporangia which are very conspicuous in the ubiquitous
black bread mold (Rhizopus nigricans).
Left: A white fungus colony resembling a Greek letter growing on
wet green moss. The colony is about one inch (2.5 cm) in diameter.
Right: Magnified view of the fungus (200x) showing silvery-white
hyphae bearing stalked mitosporangia. Each mitosporangium bears
many mitospores. These fungi are sometimes called "pin molds"
because of the resemblance of the stalked mitosporangia to roundheaded pins. They belong to the family Mucoraceae in the fungal
division Zygomycota.
See The Amazing Predatory Fungi
2. Division Eumycota (Septate Fungi)
Hyphae Of Eumycota Have Definite Cross Walls (Septa).
They Are Subdivided Into The Following Three Classes:
A. Class Ascomycetes (Cup Fungi)
Spores produced in a sac-like structure called an ascus; includes cup fungi,
yeast, leaf-curl fungi and truffles; also includes many lichenized fungi called
lichens.
Read About Truffles
See Peach Leaf Curl Gall
See A Domicile Cup Fungus
See Photographs Of Cup Fungi
Carbon Balls On Palomar Mountain
Lichenized Fungi That Grow On Rocks
See Ergot Fungus--Original Source Of LSD
B. Class Basidiomycetes (Club Fungi)
Spores produced on a club-shaped structure called a basidium; includes smut
fungi, mushrooms, toadstools, puffballs and bracket fungi; some species
contain toxic and hallucinogenic alkaloids; the mycelia of many species form
an intricate symbiotic, mycorrhizal relationship with the roots of forest trees.
Gill Fungus Life Cycle
See Anther Smut & Flowers
The Amazing Bird's Nest Fungus
See WAYNE'S WORD Fungus Article
See The Toxic "Satan's Bolete" Mushroom
Old And New World Hallucinogenic Mushrooms
See More Interesting Fungi From Palomar Mountain
Go To More Interesting Fungi From Palomar Mountain
Mr. WOLFFIA Overindulging On A Fresh Bolete Harvest
HIPPER After Overindulging On A Poisonous Gill Mushroom
C. Class Deuteromycetes (Imperfect Fungi)
This class contains fungal species in which the sexual cycle is not fully
understood; therefore, it is difficult to place them in a definite fungal class. It
includes many unusual and interesting species, including parasitic and
carnivorous fungi, and the amazing subterranean fungus gardens that leafcutter ants feed upon. Traditionally, deuteromycetes have been called the
"Fungi Imperfecti" because they do not form sexual structures; therefore they
are not complete or perfect. This large group of fungi includes the antibiotic
producer Penicillium; Aspergillus, the fermenter used in making soy sauce
and also the fungus responsible for aspergillosis, a form of pneumonia;
Candida albicans, the cause of a common vaginal infection; and
Trichophyton, which lives in skin infected with athlete's foot and groins
afflicted with jockstrap itch. Also in the class Deuteromycetes are the fungi
responsible for cryptococcosis and histoplasmosis in immunosuppressed
humans, and the dreaded Rhizocotonia, a soil-dwelling fungus causing root
rot in plants.
See The Amazing Predatory Fungi
See Economically Important Fungi
The Amazing Lichens
This group includes fungi containing symbiotic algal cells (usually Division
Chlorophyta) and/or cyanobacteria (Division Cyanophyta). Since they are
essentially lichenized fungi containing symbiotic algal or cyanobacteria cells,
they are best treated within the fungal classes Ascomycetes and
Basiodiomycetes. By far the greatest number of lichen species belong to
orders and families within the Ascomycetes.
Lichen Crust On Rocks And Desert Varnish
Economically Important Fungi
Many species in the Kingdom Fungi are very important to people. In addition
to all the delectable mushrooms, truffles and morels, there are some
economically important fungi that have played a major role in the treatment of
diseases. The antibiotic penicillin was discovered by the British scientist Sir
Alexander Fleming in 1929. He noticed that certain bacteria would not grow
in the vicinity of cultures of Penicillium mold. The discovery and eventual
isolation of the drug penicillin from this common blue mold has led to the
treatment of many human diseases and has saved countless lives. Penicillium
molds (including P. roqueforti and P. camemberti) are also used to produce
"smelly" cheeses, such as the blue, Roquefort and Camembert cheeses on your
salads and spaghetti.
Aspergillus is another genus of mold that is closely related to Penicillium.
Both economically important genera belong to the widely distributed family
Aspergillaceae (also listed as Eurotiaceae in some references). This family is
often placed in the Ascomycetes, although many authors place them in the
Deuteromycetes because their complete sexual cycle is not known. Species of
Aspergillus mold produce gallic acid used in photographic developers, dyes,
and indelible black ink. [Gallic acid was originally extracted from oak galls.]
Other species produce artificial flavorings, perfumes, chlorine and alcohols,
and are used in the manufacture of plastics, toothpaste and soap. One
interesting species of Aspergillus oryzae is used to make soy sauce by
fermenting soybeans with the fungus. It is also used in the fermentation of rice
to make sake. A Japanese food paste called "miso" is made by fermenting
soybeans, salt and rice with the same mold. Miso is used in a number of
Japanese dishes, including miso soup. According to K.R. Stern (Plant
Biology, Fifth Edition, 1991), more than one-half million tons of miso are
consumed annually.
Miso: Fermented soybean paste used in Japanese miso soup.
Another very important family of fungi is the Saccharomycetaceae which
includes nutritional food yeast (Kluyveromyces marxianus), beer, wine and
bread yeast (Saccharomyces cerevisiae), and sherry yeast (Torulaspora
delbrueckii). These microscopic fungi play a major role in the beer, wine and
baking industries. In the brewery, ethyl alcohol (ethanol) from the
fermentation process is the primary industrial product; in the bakery, carbon
dioxide released from the fermentation process causes the dough to rise.
II. Embryophytes: Zygote develops into multicellular embryo within
the female sex organ (archegonium) or within an embryo sac.
4. Kingdom Plantae:
Bryophytes: Nonvascular Embryophytes Without Water-Conducting Tissue
1. Division Bryophyta (Mosses & Liverworts)
Mosses have minute "leaves" and stalks bearing a terminal capsule
(sporangium) containing spores; moss sex organs (male antheridia and female
archegonia) are typically produced on the leafy gametophytes of separate male
and female plants; liverworts have a dorsi-ventrally flattened thallus with tiny
palmlike stalks bearing male and female sex organs; the gametophyte thallus
of some species also bears small, cuplike structures called gemmae cups; the
cups contain lens-shaped buds called gemmae which can grow asexually into
new thallus plants; there are aquatic and terrestrial forms of mosses and
liverworts, some of which have a flattened, thallus that superficially resembles
certain forms of green algae; these fascinating little nonvascular
embryophytes are often subdivided into two separate divisions.
See Photos Of Liverworts & Mosses
See Gemmae Cups Of A Liverwort
Tracheophytes: Vascular Embryophytes With Water-Conducting Tissue
A. Pteridophytes: Tracheophytes Without Seeds
2. Division Psilophyta (Psilotum)
Primitive leafless vascular plants bearing 3-lobed sporangia on branches;
includes the unusual wisk fern (Psilotum nudum; plants such as this
(including treelike forms as tall as telephone poles) were abundant in ancient
swamplands 300 million years ago.
Pteridophytes That Lived With Dinosaurs
See Close-Up View Of Psilotum Nudum
3. Division Lycophyta (Club Mosses)
Minute "true" leaves superficially resembling a moss; terminal, stalked sporebearing strobilus in Lycopodium; in Selaginella male and female sporangia
are produced in the leaf axils; also includes the bizarre quillworts (Isoetes);
many fossil forms (some tree-like) dating back 300 million years ago;
Lycopodium spores used for dust explosion demonstrations, and were used
for flash powder prior to flash bulbs and strobe lights.
See More Photos Of Pteridophytes
Pteridophytes That Lived With Dinosaurs
"Resurrection Plant" (Selaginella lepidophylla)
4. Division Sphenophyta (Horsetails)
Primitive vascular plant group of the Carboniferous Period (300 million years
ago) with jointed stems, whorls of tiny scale-like leaves at the nodes, and a
terminal spore cone (strobilus); some species with dense branches at nodes,
apparently resembling a bushy horse's tail to some botanists; also called
"scouring rushes" because the silica-impregnated stems were used to clean
pots and pans; many fossils, including tree-like forms dating back 300 million
years ago; the present-day genus Equisetum is a living fossil with several
species that are the only living representatives of this ancient group of
vascular plants.
Horsetails (Equisetum telmateia ssp. braunii) in the rain-soaked Coast
Range of northern California.
Pteridophytes That Lived With Dinosaurs
5. Division Pterophyta (Ferns)
Leaves (fronds) with sporangia clusters (sori) on the underside; fronds arising
from subterranean, creeping rhizomes and from trunks of tree-like forms
(called tree ferns); includes the orders Filicales (true ferns Adiantum,
Pteridium, Dryopteris, Polypodium, Polystichum, Pellaea, etc.),
Marsileales (clover-leaf ferns Marselia and pillworts Pillularia),
Ophioglossales (adder's tongue fern Ophioglossum), and Salviniales (water
ferns Azolla and Salvinia). Sometimes these latter "ferns" are called "fern
allies" because they belong to different orders; i.e. they do not belong to the
order Filicales (the order of true ferns).
An "air fern" (Sertularia argenta). This is NOT a true fern. It is the
skeletal remains of a dead marine hydrozoan which has been dyed
green. Hydrozoans belong to the animal Phylum Cnidaria (Class
Hydrozoa), and include many marine and freshwater species. [True
corals and sea anemones belong to the Class Anthozoa and jellyfish
belong to the Class Scyphozoa.] Hydrozoans form intricately branched
colonies attached to rocks and ocean bottoms. The fernlike branches
are composed of numerous, minute, chitinous chambers where the
individual animals once lived. When the colony was alive, a tentacle-
bearing polyp occupied each chamber (hydrotheca). The "air fern"
does not grow because it is dead. In fact, it has no roots or leaves and
the green coloring will dissolve if you soak the air fern in water. Most
commercial air ferns are collected by trawlers in the North Sea. They
are sold as a curiosity or decorative "indoor plant," and as underwater
decorations for aquaria.
Note: Although it has jellyfish characteristics, the infamous Portuguese
man-of-war (Physelia) actually belongs to the Class Hydrozoa (Order
Siphonophora). It is a large colonial animal with a bladderlike float or
air sac and long stinging tentacles that hang down in the water. An
accidental encounter with one of of these creatures can be a painful and
dangerous experience for a swimmer.
Pteridophytes That Lived With Dinosaurs
See More Photos Of Ferns And Fern Allies
Cyanobacteria Inside the Water Fern (Azolla)
B. Spermatophytes: Tracheophytes With Seeds
Gymnosperms: Tracheophytes with naked seeds. Pollen deposited
on or near the ovules (immature seeds). Seeds borne on branchlets
or on ovuliferous cone scales in woody female cones.
A modern representation of the phylogeny of gymnosperms based on
chloroplast DNA. Dichotomous (paired) sister branches (clades) with a
common ancestor are said to be monophyletic and are more closely
related. For example, the conifer division Pinophyta (Coniferophyta)
and ginkgo division (Ginkgophyta) have a common ancestor within the
cycad division (Cycadophyta). The seven major families of conebearing trees and shrubs all evolved from the division Pinophyta
(Coniferophyta). Chart by E.M. Armstrong (2008).
6. Division Cycadophyta (Cycads)
Palm-like plants with large seed and pollen cones; flourished during the days
of the dinosaurs and undoubtedly were a major food supply for herbivorous
dinosaurs; cycads were so numerous in Mesozoic times that this era is often
called the Age of Cycads and Dinosaurs; cycads are dioecious species with
pollen cones and seed cones produced on separate male and female
individuals; in some species, the enormous pollen and seed cones may reach 3
feet in length and may weigh up to 90 pounds, the largest of all living conebearing plants.
Ancient Plants Of Jurassic Park
Cycads that Lived With Dinosaurs
Cyanobacteria Living Inside Cycads
7. Division Ginkgophyta (Maidenhair Tree)
Seeds borne in pairs on dwarf shoots; leaves similar in shape to the
maidenhair fern (Adiantum); a true living fossil dating back 185 million
years; only one living representative Ginkgo biloba.
Ancient Plants Of Jurassic Park
Ginkgos That Lived With Dinosaurs
See Leaves And Fruit Of Ginkgo biloba
See The Petrified Trunk Of Ginkgo beckii
See Cell Structure Of Petrified Ginkgo beckii
See Maidenhair Trees During The Fall & Winter
Ginkgo Petrified Forest State Park In Washington
8. Division Gnetophyta (Gnetum & Welwitschia)
A remarkable plant division including Ephedra, Gnetum and Welwitschia;
stems of Ephedra are jointed with small scale-like leaves at the nodes; the
bizarre, shredded, wind-blown leaves of Welwitschia arise from a woody
caudex on the desert floor; this division includes species with vessels and
other characteristics typically found in flowering plants.
Bizarre Welwitschia and Ephedra
9. Division Coniferophyta (Cone-Bearing Trees & Shrubs)
Seeds borne on the surface of woody scales, the overlapping scales forming a
cone; includes pine (Pinus), fir (Abies), spruce (Picea), hemlock (Tsuga),
larch (Larix), juniper (Juniperus), and cypress (Cupressus); also includes
the tallest (redwood) and most massive (giant sequoia) living organisms; some
species (especially pines) require fire for seed germination and regeneration.
The World's Tallest Living Thing
See The Fire Adapted Knobcone Pine
Variation In Native Pines Of California
See A Very Large California Pine Cone
Large Cone Of Australian Bunya-Bunya
The World's Most Massive Living Thing
Foxtail Pines In California's Sierra Nevada
Nutmeg & Yew: Conifers With Naked Seeds
Podocarpus: Conifer With Fleshy Naked Seeds
Fabulous Wood & Cones Of The Araucaria Family
Angiosperms: Flowering plants. Seeds enclosed within ripened ovary
(fruit). The fruit may be fleshy or dry at maturity, and dehiscent or
indehiscent. More than 90% of all plants on earth are angiosperms.
10. Division Anthophyta (Flowering Plants)
Amazing Diversity Of Flowering Plants
Class Monocotyledoneae: Monocots. Flower parts in 3's or multiple of
3's; one cotyledon inside seed; parallel leaf venation; includes Lilium,
Amaryllis, Iris, Agave, Yucca, orchids, duckweeds, grasses, & palms.
Class Dicotyledoneae: Dicots. Flower parts in 4's or 5's; 2 cotyledons
inside seed; branched or net leaf venation; includes the most species
of flowering herbs, shrubs and trees.
Characteristics Of Monocots & Dicots
Most of the botanical records listed in Botanical Record-Breakers
(WAYNE'S WORD Volume 6 Spring 1997) belong to the amazing
flowering plants. In fact, most of the plant articles featured in
WAYNE'S WORD are angiosperms. They can easily be found using
the Index. Flowering plant records include the following links:
The Oldest Living Thing
Hardest And Heaviest Wood
Smallest Flowering Plant
Smallest And Largest Fruit
The Largest Vegetable
Smallest And Largest Seed
Record Distance For Drift Seed
Fastest Reproducing Plants
The Fastest Growing Plants
The Deadliest Plants
The Most Painful Plants
Most Valuable Plant Jewels
Other WAYNE'S WORD articles about amazing and little-known
flowering plants can easily be found using the Index. Some of the
more notable articles include the following:
Smallest Flowering Plant
The Smallest Fruit
The Largest Fruit
The Largest Vegetable
The Longest Bean Pod
An Amazing Drift Seed
Worst Smelling Plants
Amazing Fungus Flowers
Post-Burn Wildflowers
Plants That Make Amber
The Ultimate Hitchhikers
Hitchhikers On Big Animals
Ocean Drift Seeds & Fruits
Bat-Pollinated Lianas
Marine Sea Grasses
Wind Seed & Fruit Dispersal
Plants That Make You Loco
Poison Oak Makes You Itch
Vegetable Ivory From Palms
The Amazing Castor Bean
Job's Tears: Perfect Beads
Natural Jewelry From Plants
The Truth About Cauliflory
Calimyrna Fig & Its Wasp
Galls: Growths On Plants
Soap Lilies In California
Beautiful Morning Glories
The Amazing Gourd Family
The Carnivorous Plants
Swollen-Thorn Acacias
5. Kingdom Animalia:
Go To The Major Phyla Of Animals
Multicellular animals not usually included in botany courses; without cell
walls and without photosynthetic pigments, forming diploid blastula; there are
more than one million species of animals in at least 30 phyla, more species
than all the other kingdoms combined; more than half of all animal species are
insects (800,000 species), and beetles (300,000 species) comprise the largest
order of insects (one fifth of all species based on a total of 1.5 million); if all
the species of plants and animals on earth were lined up at random, every 5th
species would be a beetle.
See The World Of Beetles
References
1. Bold, H.C. and M.J. Wynne. 1985. Introduction to the Algae.
Prentice-Hall, Inc., Englewood Cliffs, New Jersey.
2. Brock, T.D. and M.T. Madigan. 1988. The Biology of
Microorganisms. Prentice-Hall, Englewood Cliffs, New Jersey.
3. Margulis, L., K.V. Schwartz, and M. Dolan. 1994. The Illustrated
Five Kingdoms: A Guide To The Diversity Of Life On Earth.
HarperCollins College Publishers, New York.
4. Stern, K.R. 1991. Introductory Plant Biology (Fifth Edition). Wm. C.
Brown Publishers, Dubuque, Iowa.
5. Thorne, R.F. 1992. "Classification and Geography of the Flowering
Plants." The Botanical Review 58 (3): 225-350.
6. Thorne, R.F. 1992. "An Updated Phylogenetic Classification of the
Flowering Plants." Aliso 13 (2): 365-389.
Return To WAYNE'S WORD Home Page
Return To NOTEWORTHY PLANTS Page
Go To Biology GEE WHIZ TRIVIA Page
Go To The LEMNACEAE ON-LINE Page
XXXXXXXXXXXXXXXXXXXXXXXx
Source: wikipedia http://en.wikipedia.org/wiki/Kingdom_%28biology%29 29-12
From Wikipedia, the free encyclopedia
Jump to: navigation, search
The hierarchy of biological classification's eight major taxonomic ranks, which is an
example of definition by genus and differentia. A domain contains one or more
kingdoms. Intermediate minor rankings are not shown.
In biology, kingdom (Latin: regnum, pl. regna) is a taxonomic rank, which is either
the highest rank or in the more recent three-domain system, the rank below domain.
Kingdoms are divided into smaller groups called phyla (in zoology) or divisions in
botany. The complete sequence of ranks is life, domain, kingdom, phylum, class, order,
family, genus, and species.
Currently, textbooks from the United States use a system of six kingdoms (Animalia,
Plantae, Fungi, Protista, Archaea, Bacteria) while British, Australian and Latin
American textbooks may describe five kingdoms (Animalia, Plantae, Fungi, Protista,
and Prokaryota or Monera).
Historically, the number of kingdoms in widely accepted classifications has grown from
two to six. However, phylogenetic research from about 2000 onwards does not support
any of the traditional systems.
Contents
[hide]











1 Two kingdoms
2 Three kingdoms
3 Four kingdoms
4 Five kingdoms
5 Six kingdoms
6 Cavalier-Smith's six kingdoms
7 International Society of Protistologists Classification 2005
8 Summary
9 See also
10 References
11 External links
[edit] Two kingdoms
The classification of living things into animals and plants is an ancient one. Aristotle
(384 BC–322 BC) classified animal species in his work the History of Animals, and his
pupil Theophrastus (c. 371–c. 287 BC) wrote a parallel work on plants (the History of
Plants).[1]
Carolus Linnaeus (1707–1778) laid the foundations for modern biological
nomenclature, now regulated by the Nomenclature Codes. He distinguished two
kingdoms of living things: Regnum Animale ('animal kingdom') for animals and
Regnum Vegetabile ('vegetable kingdom') for plants. (Linnaeus also included minerals,
placing them in a third kingdom, Regnum Lapideum.) Linnaeus divided each kingdom
into classes, later grouped into phyla for animals and divisions for plants.
life
Regnum Vegetabile
Regnum Animale
[edit] Three kingdoms
In 1674, Antonie van Leeuwenhoek, often called the "father of microscopy", sent the
Royal Society of London a copy of his first observations of microscopic single-celled
organisms. Up to this time, the existence of such microscopic organisms was entirely
unknown. At first these organisms were divided into animals and plants and placed in
the appropriate Kingdom. However, by the mid-19th century it had become clear that
"the existing dichotomy of the plant and animal kingdoms [had become] rapidly blurred
at its boundaries and outmoded".[2] In 1866, following earlier proposals by Richard
Owen and John Hogg, Ernst Haeckel proposed a third kingdom of life. Haeckel revised
the content of this kingdom a number of times before settling on a division based on
whether organisms were unicellular (Protista) or multicellular (animals and plants).[2]
life
Kingdom Protista
Kingdom Plantae
Kingdom Animalia
[edit] Four kingdoms
The development of microscopy, and the electron microscope in particular, revealed an
important distinction between those unicellular organisms whose cells do not have a
distinct nucleus, prokaryotes, and those unicellular and multicellular organisms whose
cells do have a distinct nucleus, eukaryotes. In 1938, Herbert F. Copeland proposed a
four-kingdom classification, moving the two prokaryotic groups, bacteria and "bluegreen algae", into a separate Kingdom Monera.[2]
life
Kingdom Monera (prokaryotes, i.e. bacteria and "blue-green algae")
Kingdom Protista (single-celled eukaryotes)
Kingdom Plantae
Kingdom Animalia
It gradually became apparent how important the prokaryote/eukaryote distinction is, and
Stanier and van Niel popularized Édouard Chatton's proposal in the 1960s to recognize
this division in a formal classification. This required the creation, for the first time, of a
rank above kingdom, a superkingdom or empire, also called a domain.[3]
life
Empire Prokaryota
Empire Eukaryota
Kingdom Monera
Kingdom Protista
Kingdom Plantae
Kingdom Animalia
[edit] Five kingdoms
The differences between fungi and other organisms regarded as plants had long been
recognized. For example, at one point Haeckel moved the fungi out of Plantae into
Protista, before changing his mind.[2] Robert Whittaker recognized an additional
kingdom for the Fungi. The resulting five-kingdom system, proposed in 1969 by
Whittaker, has become a popular standard and with some refinement is still used in
many works and forms the basis for newer multi-kingdom systems. It is based mainly
on differences in nutrition; his Plantae were mostly multicellular autotrophs, his
Animalia multicellular heterotrophs, and his Fungi multicellular saprotrophs. The
remaining two kingdoms, Protista and Monera, included unicellular and simple cellular
colonies.[4] The five kingdom system may be combined with the two empire system.
life
Empire Prokaryota
Empire Eukaryota
Kingdom Monera
Kingdom Protista
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
[edit] Six kingdoms
From around the mid-1970s onwards, there was an increasing emphasis on molecular
level comparisons of genes (initially ribosomal RNA genes) as the primary factor in
classification; genetic similarity was stressed over outward appearances and behavior.
Taxonomic ranks, including kingdoms, were to be groups of organisms with a common
ancestor, whether monophyletic (all descendants of a common ancestor) or paraphyletic
(only some descendants of a common ancestor). Based on such RNA studies, Carl
Woese divided the prokaryotes (Kingdom Monera) into two groups, called Eubacteria
and Archaebacteria, stressing that there was as much genetic difference between these
two groups as between either of them and all eukaryotes. Eukaryote groups, such as
plants, fungi and animals may look different, but are more similar to each other in their
genetic makeup at the molecular level than they are to either the Eubacteria or
Archaebacteria. (It was also found that the eukaryotes are more closely related,
genetically, to the Archaebacteria than they are to the Eubacteria.) Although the
primacy of the eubacteria-archaebacteria divide has been questioned, it has also been
upheld by subsequent research.[5]
XXOO
Woese attempted to establish a "three primary kingdom" or "urkingdom" system.[6] In
1990, the name "domain" was proposed for the highest rank.[7] The six-kingdom system
shown below represents a blending of the classic five-kingdom system and Woese's
three-domain system. Such six-kingdom systems have become standard in many works.
life
Domain Bacteria
Domain Archaea
Domain Eukarya
Kingdom Bacteria
Kingdom Archaea
Kingdom Protista
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
Woese also recognized that the Protista kingdom was not a monophyletic group and
might be further divided at the level of kingdom.
[edit] Cavalier-Smith's six kingdoms
Thomas Cavalier-Smith has published extensively on the evolution and classification of
life, particularly protists. His views have been influential but controversial, and not
always widely accepted.[8] In 1998, he published a six-kingdom model,[9] which has
been revised in subsequent papers. The version published in 2009 is shown below.[10]
(Compared to the version he published in 2004,[11] the alveolates and the rhizarians have
been moved from Kingdom Protozoa to Kingdom Chromista.) Cavalier-Smith does not
accept the importance of the fundamental eubacteria–archaebacteria divide put forward
by Woese and others and supported by recent research.[5] His Kingdom Bacteria
includes the Archaebacteria as part of a subkingdom along with a group of eubacteria
(Posibacteria). Nor does he accept the requirement for groups to be monophyletic. His
Kingdom Protozoa includes the ancestors of Animalia and Fungi. Thus the diagram
below does not represent an evolutionary tree.
life
Empire Prokaryota
Empire Eukaryota
Kingdom Bacteria — includes Archaebacteria as
part of a subkingdom
Kingdom Protozoa — e.g. Amoebozoa, Choanozoa,
Excavata
Kingdom Chromista — e.g. Alveolata, cryptophytes,
Heterokonta (stramenopiles), Haptophyta, Rhizaria
Kingdom Plantae — e.g. glaucophytes, red and green
algae, land plants
Kingdom Fungi
Kingdom Animalia
See also: Thomas Cavalier-Smith
[edit] International Society of Protistologists
Classification 2005
One hypothesis of eukaryotic relationships, modified from Simpson and Roger (2004).
The "classic" six-kingdom system is still recognizably a modification of the original
two-kingdom system: Animalia remains; the original category of plants has been split
into Plantae and Fungi; and single-celled organisms have been introduced and split into
Bacteria, Archaea and Protista.
Research published in the 21st century has produced a rather different picture. In 2004,
a review article by Simpson and Roger noted that the Protista were "a grab-bag for all
eukaryotes that are not animals, plants or fungi". They argued that only monophyletic
groups–an ancestor and all of its descendents — should be accepted as formal ranks in a
classification. On this basis, the diagram opposite (redrawn from their article) showed
the real "kingdoms" (their quotation marks) of the eukaryotes.[12] A classification
produced in 2005 for the International Society of Protistologists, which reflected the
consensus of the time[citation needed], followed this approach, dividing the eukaryotes into
the same six "supergroups".[13] Although the published classification deliberately did
not use formal taxonomic ranks, other sources[citation needed] have treated each of the six as
a separate Kingdom.
life
Domain Bacteria
Domain Archaea
Domain Eukarya
Bacteria
Archaea
Excavata — Various flagellate protozoa
Amoebozoa — most lobose amoeboids and slime
moulds
Opisthokonta — animals, fungi, choanoflagellates,
etc.
Rhizaria — Foraminifera, Radiolaria, and various
other amoeboid protozoa
Chromalveolata — Stramenopiles (or Heterokonta),
Haptophyta,Cryptophyta (or cryptomonads), and
Alveolata
Archaeplastida (or Primoplantae) — Land plants,
green algae, red algae, and glaucophytes
In this system, the traditional kingdoms have vanished. For example, research shows
that the multicellular animals (Metazoa) are descended from the same ancestor as the
unicellular choanoflagellates and the fungi. A classification system which places these
three groups into different kingdoms (with multicellular animals forming Animalia,
choanoflagellates part of Protista and Fungi a separate kingdom) is not monophyletic.
The monophyletic group is the Opisthokonta, made up of all those organisms believed
to have descended from a common ancestor, some of which are unicellular
(choanoflagellates), some of which are multicellular but not closely related to animals
(some fungi), and others of which are traditional multicellular animals.[13]
However, in the same year as the International Society of Protistologists' classification
was published (2005), doubts were being expressed as to whether some of these
supergroups were monophyletic, particularly the Chromalveolata,[14] and a review in
2006 noted the lack of evidence for several of the supposed six supergroups.[15]
As of 2010, there is widespread agreement that the Rhizaria belong with the
Stramenopiles and the Alveolata, in a clade dubbed the SAR supergroup[citation needed], so
that Rhizara is not one of the main eukaryote groups.[10][16][17][18][19] Beyond this, there
does not appear to be a consensus. Rogozin et al. in 2009 noted that "The deep
phylogeny of eukaryotes is an extremely difficult and controversial problem."[20] As of
December 2010, there appears to be a consensus that the 2005 six supergroup model
does not reflect the true phylogeny of the eukaryotes and hence how they should be
classified, although there is no agreement as to the model which should replace
it.[17][21][22]
[edit] Summary
The sequence from the two-kingdom system up to Cavalier-Smith's six-kingdom system
can be summarized in the table below.
Copelan
Whittake
Woese Cavalier
Haeckel Chatton
d
Linnaeus
r
et al. -Smith
1866[24] 1925[25][26 1938[27][2
Woese et al.
[23]
[4]
1735
1969
1990[30] 2004[11]
]
8]
3
1977[6][29]
2
5
3
6
kingdom
2
4
6 kingdoms
kingdoms
kingdom
domain kingdom
s
empires kingdom
s
s
s
s
Eubacteria
Bacteria
Prokaryot
Monera Monera Archaebacteri
Bacteria
a
Archaea
a
(not
Protista
treated)
Protozoa
Protista
Protista
Protoctist
Chromist
a
a
Eukaryot
Eukarya
a
Fungi
Fungi
Fungi
Vegetabili
Plantae
a
Plantae Plantae Plantae
Plantae
Animalia Animalia
Animalia Animalia Animalia
Animalia
Note that the equivalences in this table are not perfect. For example, Haeckel placed the
red algae (his Florideae, modern Florideophyceae) and blue-green algae (his
Archephyta, modern Cyanobacteria) in his Plantae.
One or other of the kingdom-level classifications of life is still widely employed as a
useful way of grouping organisms, notwithstanding the problems with this approach:


Kingdoms such as Bacteria represent grades rather than clades, and so are
rejected by phylogenetic classification systems.
Research in the 21st century does not support the classification of the eukaryotes
into any of the standard systems. As of April 2010, the situation appears to be
that there is no set of kingdoms sufficiently supported by current research to
gain widespread acceptance; as Roger & Simpson say: "with the current pace of
change in our understanding of the eukaryote tree of life, we should proceed
with caution." [31]
[edit] See also


Cladistics
Systematics
[edit] References
1. ^ Singer, Charles J. (1931), A short history of biology, a general introduction to
the study of living things, Oxford: Clarendon Press, OCLC 1197036
2. ^ a b c d Scamardella, Joseph M. (1999), "Not plants or animals: a brief history of
the origin of Kingdoms Protozoa, Protista and Protoctista", International
Microbiology 2 (4): 207–16, PMID 10943416
3. ^ Stanier, R.Y. & Van Neil, C.B. (1962), "The concept of a bacterium", Archiv
Für Mikrobiologie 42: 17–35, doi:10.1007/BF00425185, PMID 13916221
4. ^ a b Whittaker, R.H. (January 1969), "New concepts of kingdoms or organisms.
Evolutionary relations are better represented by new classifications than by the
traditional two kingdoms", Science 163 (863): 150–60, PMID 5762760,
http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=5762760
5. ^ a b Dagan, T.; Roettger, M.; Bryant, D & Martin, W. (2010), "Genome
Networks Root the Tree of Life between Prokaryotic Domains", Genome
Biology and Evolution 2:: 379–92, doi:doi:10.1093/gbe/evq025
6. ^ a b Balch, W.E.; Magrum, L.J.; Fox, G.E.; Wolfe, C.R.; & Woese, C.R.
(August 1977), "An ancient divergence among the bacteria", J. Mol. Evol. 9 (4):
305–11, doi:10.1007/BF01796092, PMID 408502
7. ^ Woese, C.R.; Kandler, O. & Wheelis, M. (1990), "Towards a natural system
of organisms: proposal for the domains Archaea, Bacteria, and Eucarya", Proc
Natl Acad Sci U S A 87 (12): 4576–9, doi:10.1073/pnas.87.12.4576,
PMID 2112744
8. ^ Palaeos.com, Origins of the Eukarya, archived from the original on 2010-0429, http://www.webcitation.org/5pLfYf6U7, retrieved 2010-04-29
9. ^ Cavalier-Smith, T. (1998), "A revised six-kingdom system of life", Biological
Reviews 73 (03): 203–66, doi:10.1017/S0006323198005167,
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=685
10. ^ a b Cavalier-Smith, Thomas (2009), "Kingdoms Protozoa and Chromista and
the eozoan root of the eukaryotic tree", Biology Letters 6: 342–5,
doi:10.1098/rsbl.2009.0948
11. ^ a b Cavalier-Smith, T. (2004), "Only six kingdoms of life", Proc. R. Soc. Lond.
B 271 (1545): 1251–62, doi:10.1098/rspb.2004.2705, PMID 15306349,
PMC 1691724, http://www.cladocera.de/protozoa/cavalier-smith_2004_prs.pdf,
retrieved 2010-04-29
12. ^ Simpson, Alastair G.B. & Roger, Andrew J. (2004), "The real ‘kingdoms’ of
eukaryotes", Current Biology 14 (17): R693–6, doi:10.1016/j.cub.2004.08.038,
PMID 15341755
13. ^ a b Adl, Sina M.; et al. (2005), "The New Higher Level Classification of
Eukaryotes with Emphasis on the Taxonomy of Protists", Journal of Eukaryotic
Microbiology 52 (5): 399, doi:10.1111/j.1550-7408.2005.00053.x,
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1550-7408.2005.00053.x
14. ^ Harper, J.T.; Waanders, E. & Keeling, P. J. (2005), "On the monophyly of
chromalveolates using a six-protein phylogeny of eukaryotes", Nt. J. System.
Evol. Microbiol. 55 (Pt 1): 487–496, doi:10.1099/ijs.0.63216-0,
PMID 15653923, http://www.botany.ubc.ca/keeling/PDF/05chromalvJSEM.pdf
15. ^ Parfrey, Laura W.; Barbero, Erika; Lasser, Elyse; Dunthorn, Micah;
Bhattacharya, Debashish; Patterson, David J. & Katz, Laura A. (2006),
"Evaluating Support for the Current Classification of Eukaryotic Diversity",
PLoS Genet. 2 (12): e220, doi:10.1371/journal.pgen.0020220, PMID 17194223,
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http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=17
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Skjæveland, Sergey I. Nikolaev, Kjetill S. Jakobsen, Jan Pawlowski (2007).
"Phylogenomics Reshuffles the Eukaryotic Supergroups". PLoS ONE 2 (8):
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17. ^ a b Burki, Fabien; Shalchian-Tabrizi, Kamran; Pawlowski, Jan (2008).
"Phylogenomics reveals a new 'megagroup' including most photosynthetic
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18. ^ Burki, F. et al. (2009), "Large-Scale Phylogenomic Analyses Reveal That
Two Enigmatic Protist Lineages, Telonemia and Centroheliozoa, Are Related to
Photosynthetic Chromalveolates", Genome Biology and Evolution 1: 231–8,
doi:10.1093/gbe/evp022
19. ^ Hackett, J.D.; Yoon, H.S.; Li, S.; Reyes-Prieto, A.; Rummele, S.E. &
Bhattacharya, D. (2007), "Phylogenomic analysis supports the monophyly of
cryptophytes and haptophytes and the association of Rhizaria with
chromalveolates", Mol. Biol. Evol. 24: 1702–13, doi:10.1093/molbev/msm089
20. ^ Rogozin, I.B.; Basu, M.K.; Csürös, M. & Koonin, E.V. (2009), "Analysis of
Rare Genomic Changes Does Not Support the Unikont–Bikont Phylogeny and
Suggests Cyanobacterial Symbiosis as the Point of Primary Radiation of
Eukaryotes", Genome Biology and Evolution 1: 99–113,
doi:10.1093/gbe/evp011
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Åsmund; Nikolaev, Sergey I.; Jakobsen, Kjetill S. & Pawlowski, Jan (2007),
"Phylogenomics Reshuffles the Eukaryotic Supergroups", PLoS ONE 2 (8):
e790, doi:10.1371/journal.pone.0000790, PMID 17726520, PMC 1949142,
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challenges the monophyly of Archaeplastida and Chromalveolata", PLoS ONE 3
(7): e2621, doi:10.1371/journal.pone.0002621, PMID 18612431
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proposita per classes, ordines, genera & species.
24. ^ E. Haeckel (1866). Generelle Morphologie der Organismen. Reimer, Berlin.
25. ^ É. Chatton (1925). "Pansporella perplexa. Réflexions sur la biologie et la
phylogénie des protozoaires". Ann. Sci. Nat. Zool 10-VII: 1–84.
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