• Aristotle:
about 2,300 years BP
Plants and animals, habitats and physical differences
• Carolus Linnaeus:
in the late 1700s
The system we have today, with the kingdoms
Linnaeus classified organisms not just by structural similarities and differences,
but by evolutionary relationships.
We are unsure of the true number of species
on Earth, but up to now scientists have
classified:
• 1.4 million
The true total number of species is
estimated between: • 2-100 million
In the Linnaean system, kingdoms are the largest taxon, or
grouping of organisms. However, recently scientists have
described yet a larger taxon.
There are three domains, into
which scientists have grouped
all living things:
• Archaea
• Eubacteria
•Eukarya
Prokaryotes
Eukaryotes
Classification
The science of classification is known as TAXONOMY.
Taxonomic nomenclature is a fancy way of saying “our scientific system of
naming orgainsms”.
Binomial nomenclature is the part of taxonomic nomenclature that contains the
final two classifications…that of Genus, and species.
Binomial nomenclature is the most common two
name system known to science.
Domain:
What is the binomial
nomenclature of humans?
ANS: Homo sapiens
Eukarya
Kingdom:
Animalia
Chordata
Phylum:
TAXONOMIC
NOMENCLATURE OF
HUMANS:
Mammalia
Class:
Primates
Order:
Family:
Genus:
Hominidae
Homo
Species:
sapiens
Taxonomy, the classification of organisms according to
similarity, has been influenced by phylogenetics.
Classification of Living Things
DOMAIN
KINGDOM
Bacteria
Archaea
Eubacteria
Archaebacteria
Eukarya
Protista
Fungi
Plantae
Animalia
CELL TYPE
Prokaryote
Prokaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
CELL
STRUCTURES
Cell walls with
peptidoglycan
Cell walls without
peptidoglycan
Cell walls of cellulose
in some; some have
chloroplasts
Cell walls of chitin
Cell walls of
cellulose;
chloroplasts
No cell
walls or
chloroplasts
NUMBER OF
CELLS
Unicellular
Unicellular
Most unicellular; some
colonial; some
multicellular
Most multicellular;
some unicellular
Multicellular
Multicellular
MODE OF
NUTRITION
Autotroph or
heterotroph
Autotroph or
heterotroph
Autotroph or
heterotroph
Heterotroph
Autotroph
Heterotroph
EXAMPLES
Streptococcus,
Escherichia coli
Methanogens,
halophiles
Amoeba, Paramecium,
slime molds, giant kelp
Mushrooms, yeasts
Mosses, ferns,
flowering plants
Sponges,
worms,
insects,
fishes,
mammals
Classification of Four Organisms
Corn
Whale
Shark
Humpback
Whale
Eukarya
Spider
Monkey
Kingdom
Plantae
Animalia
Animalia
Animalia
Phylum
Anthophyta
Chordata
Chordata
Chordata
Class
Monocotyledones
Chondrichthyes
Mammalia
Mammalia
Order
Commelinales
Squaliformes
Cetacea
Primates
Family
Poaceae
Rhincodontidae
Balaenopteridae
Atelidae
Genus
Zea
Rhincodon
Megaptera
Ateles
Species
Zea mays
Rhinacodon typus
Megaptera
novaeangilae
Ateles paniscus
Pay close
attention to
this
taxonomic
table,
because the
activity
designed for
later, and
tomorrow will
have you
designing
one of your
own.
You can tell simply by looking at this taxonomic table, which organisms
are more closely related by observing their similarities. The more they
have in common…the more related they are. Which two organisms are
most closely related? To what domain would all these organisms belong?
Notice that
as you move
down
through the
“taxons”, you
see more and
more
specificity,
and fewer
and fewer
organisms…
Into what domain would plants fit?
Eukarya
until finally,
you arrive at
the species,
and there is
only one!
• Archaebacteria
• Eubacteria
• Protista
• Fungi
Monerans
Algae, protozoans, and slime molds
Mushrooms, molds, yeasts and lichens
• Plantae
• Animalia
Plants
Animals
There are only a couple hundred species of archaebacteria
that have been classified on Earth, and most of them live in
extreme environments.
An extremophile is an organism that thrives under
All archaebacteria are
"extreme" conditions, such as:
unicellular prokaryotes, and
• low or high pH
lack distinct membrane bound
• high salt concentration organelles… but unlike
• high temperatures
Eubacteria, Archaebacteria do
not have peptidoglycan in their
• low temperatures
cell walls.
• Autotrophs
• Heterotrophs
• Chemotrophs
Interestingly, archaebacteria have complex
genetic makeup, and their genes have similar
structure to those found in eukaryotes (far
more complex organisms). Questions have been
raised about which came first, as a result!
Just as the archaebacteria, Eubacteria are all unicellular
prokaryotes…but some live in colonial fashion. There are
10,000 described species.
They have extremely strong cell walls, no defined nucleus or
membrane bound organelles, and a less complex genetic
makeup than found in archaebacteria and eukaryotes.
While some Eubacteria are known to
cause diseases, such as strep throat
and pneumonia, most are harmless
and indeed are actually helpful, like
Lactobacillus acidophilus
Kingdom Protista is hugely diverse (250,000 species). While
most are unicellular, some are multicellular, but they all
share some common characteristics.
Protists are eukaryotes that lack complex organ systems
and live in moist environments. • Some are animal-like
• Some are plant-like autotrophs heterotrophs
• Still others are fungi-like
heterotrophs
With the diversity of
this kingdom in mind,
many scientists believe
it should be divided to
make it more
manageable.
Organisms in Kingdom Fungi are heterotrophs that do not
move from place to place.
They can be either unicellular or multicellular eukaryotes
that absorb nutrients from organic materials in the
environment.
There are more than 50,000 known species of fungi, and
they are all decomposers.
Puffball
fly agarics
mushroom
Stinkhorn
Yeast
Most fungi are decomposers,
and they digest things
extracellularly, and then
absorb the nutrients through
a network of “root-like”
structures known as hyphae.
Sometimes the fungus doesn't
wait for the organism to die, in
which case the fungus is called
a parasite.
Another thing that sets fungi
apart from plants and other
organisms with cell walls, is the
presence of chitin.
Chitin is a polysaccharide that is beneficial as a
structural strengthener in the fungi organism.
• All plants are multicellular autotrophic eukaryotes.
• Plants are sessile.
• Cells usually contain chloroplasts to help in the
production of sugars during photosynthesis.
• Cell walls which contain cellulose.
• Plant “bodies” are organized from
cells, to tissues, to organs, to organ
systems.
There are more than
250,000 species of plants
described on Earth today.
While the more familiar
flowering plants exist,
don’t forget about the
lowly mosses, ferns and
evergreens
Like plants, all animals are multicellular. Unlike plants,
however, all animals are heterotrophs.
• Nearly all of them move from place to place
• Animal cells do not contain cell walls, or chloroplasts
• Animal “bodies” are organized into cells, tissues, organs
and organ systems.
There are an amazing 1,000,000
species of described animals on
Earth.
Animals range from
the most simple
invertebrate sponge,
to the most complex
vertebrate mammal.
Porifera
Annelids
MollusksPlatyhelminthes
NematodaRotifera
Cnidarians
Echinoderms
Arthropods
Classification of Four Organisms
Corn
Whale
Shark
Humpback
Whale
Spider
Monkey
Kingdo
m
Plantae
Animalia
Animalia
Animalia
Phylum
Anthophyta
Chordata
Chordata
Chordata
Class
Monocotyledon
es
Chondrichthyes
Mammalia
Mammalia
Order
Commelinales
Squaliformes
Cetacea
Primates
Family
Poaceae
Rhincodontidae
Balaenopterid
ae
Atelidae
Genus
Zea
Rhincodon
Megaptera
Ateles
Species
Zea mays
Rhinacodon
typus
Megaptera
novaeangilae
Ateles
paniscus
Then, students will draw and color these four
organisms for placement on their posters. Have
some fun with this!
The humpback whale and the spider monkey
diverge at the order taxon. This makes them the
most closely related of all four.
The three animals are most distantly related to the
plant at the kingdom taxon.
Hopefully, this table looks
familiar to you!
•Each lab group will get
a random list of 10
organisms to classify
based upon their
taxonomic
nomenclature.
•Students will research
each of these
organisms, and place
them in a classification
table such as this.
•Based upon their
classification, students
will then decide which
two are most closely
related, and which two
(or more) are most
distantly related.
•They will justify that
relationship with data
they found while
researching.