Kingdom in Biology
The system of biological kingdoms- way in which science classifies living things
according to their ancestry over the course of evolution.
Trivia:
Aristotle, the Greek philosopher: planet biodiversity was of animal and plant origin. This
concept of two kingdoms was accepted in the 19th and 20th century.
Living organisms as classified by Haekel in 1866
Multicellular
Animals
Plants
Unicellular
Protists
Algae
Protozoa
Fungi
Molds
Yeasts
Bacteria
Eukaryotes
Prokaryotes
Four-kingdom system was established by the American Herbert Copeland in 1956.
Robert Whittaker, North American ecologist proved in 1959 that fungi were not plant
organism. He proposed fungi kingdom which scientific community accepted, thus Fivekingdom system.
CHARACTERISTICS OF THE FIVE KINGDOMS OF LIVING THINGS
All the species in a particular kingdom have similar characteristics in terms of their
growth and the way they function.
1. Nutrition. All biological systems, from microorganisms to man, share a set of
nutritional requirements,
a) Source of energy
Phototrophs: organisms capable of employing radiant energy
Chemotrophs; organisms which obtain the energy for their activities and selfsynthesis from chemical reactions that can occur in the dark.
b) Source of carbon
Autotrophs:organisms which can thrive on an inorganic diets, using CO2 or
carbonate as a sole source of carbon
Heterotrophs: organisms which cannot use CO2 as a sole source of carbon
but require, in addition to minerals, one more organic substances such as
glucose or amino acid as source of carbon.
Autotrophic-makes its own food
heterotrophic -feeds on other living things
c) Source of nitrogen: atmospheric nitrogen, inorganic nitrogen compounds or
other derived nitrogen
d) Source of sulfur and phosphorus: elementary sulfur, inorganic sulfur or
organic sulfur
e) Sources of metallic elements: sodium, potassium, calcium, magnesium,
manganese, iron, zinc, copper, and cobalt
f) Sources of vitamin.
2. Cell organization
Unicellular-having only one cell
Multicellular- having two or more cells
3. Cell type.
Eukaryotes-the genetic material is surrounded by a membrane
prokaryotes -lacking a membrane.
4. Respiration.
Aerobic -needs oxygen
anaerobic -does not use oxygen
Facultative: survives in the presence or absence of oxygen
5. Reproduction. Sexual, asexual or through spores.
6. Movement. Self-moving or static.
Five Kingdoms
1.Kingdom Animalia
*The most evolved.
Tsunami-nuclear fall-out in Japan; Nagasaki bombing WW11
*Division into large groups: vertebrates and invertebrates.
*Multi-celled, heterotrophic eukaryotes with aerobic respiration, sexual reproduction and
motile.
*This kingdom is one of the most diverse and comprises mammals, fish, birds, reptiles,
amphibians, insects, molluscs, echinoderms, crustaceans, arachnoids, cridaria(jelly
fish), porifera and annelids.
2.Plantae kingdom
*one of the oldest, and characterized by its immobile, multicellular and eukaryotic
nature.
*autotrophic. Cellulose and chlorophyll are essential for life on Earth since they
release oxygen through photosynthesis.
*method of reproduction: either sexual or asexual.
*Trees, plants and other species of vegetation.
Gymnosperm
Angiosperm
Fern
Moss
3.Fungi kingdom which includes yeasts, molds and all species of mushrooms and
toadstools.
*Multicellular aerobic heterotrophic eukaryotes have chitin in their cell walls, feed off
other living things, and reproduce through spores.
4.The Protista kingdom is paraphyletic - it contains the common ancestor but not all its
descendants
*The most primitive of the eukaryotics and all the others are descendants of it.
* It includes those eukaryotic organisms that are not deemed to be animals,
plants or fungi such as protozoa.
*. It is so heterogeneous it is difficult to categorixe it, since its members have very little
thing in common.
5.Monera Kingdom
*The kingdom of microscopic living things and groups together the prokaryotes (archaea
and bacteria).
*This group is present in all habitats and is made up of single-cell things with no
defined nucleus.
*Most bacteria are aerobic and heterotrophic, while the archaea are usually anaerobic
and their metabolism is chemosynthetic.
The classification of the five kingdoms of nature remains the most accepted
today, although the latest advances in genetic research have suggested new revisions
and reopened the debate among experts. Such is the case for the sixth kingdom of Carl
Woese and George Fox, who in 1977 divided bacteria into two types (Archaea and
Bacteria), and the seventh kingdom of Cavalier-Smith, who added a new group to the
previous six for algae called Chromista.
HIERARCHY/other taxonomic categories within the same classification.
→domain
→phylum
→class
→order
→family
→genus
→species
Sub-species
Microbial nomenclature: binomial system, italized
1.First word (capitalized) is the name of the genus(plural, genera). Genus name is Latin
or Greek word.
Genus names and their meanings:
Bacillus: a small rod
Lactobacillus: a small milk rod
Micrococcus: a small grain
Clostridum: a small spindle
Pasteurella: after Louis Pasteur, Latinized
Salmonella:after Daniel E. Salmon, Latinized
Saccharomyces:sugar fungus
2. Second name is the species name and is not capitalized.
When several species with the same genus, abbreviation is allowed:
Bacillus subtilis, B. albus, B. coagulans.
Mycobacterium tuberculosis, M. leprae,
Scientific names of plants follow the binomial system:
Corchorus capsularis, Vitex negundo, Morus alba, Zingiber officinale
Bacteria
*unicellular microscopic organisms
*about 1,500 known species occurring in natural environment
*typical diameter: 0.5 to 1 µm
*variety of shapes:
Cocci: spherical or ovoid
Bacilli: cylindrical or rod shaped
Spirilla: helically coiled
Reproduction process
Bacteria multiply through asexual process called binary fission which involve the
following steps:
(1) cell elongation
(2) invagination of the cell wall
(3) distribution of nuclear material
(4) formation of the transverse cell wall
(5) distribution of cellular material into two cells
(6) separation into two new cells.
Nutritional Requirements.
Elemental composition of bacteria as enumerated below should be present in their
nutritional medium in laboratory culture for bacterial growth
Elemental composition of Bacteria
Components
Dry weight %
Carbon
50
Oxygen
20
Nitrogen
14
Hydrogen
8
Phosphorus
3
Sulfur
1
Metals
4
Physical Conditions. Three physical factors in which bacteria grow best.
1. Temperature.
Microbial activity and growth are manifestation of enzymatic acid. Since the rate
of enzyme reactions increase with increasing temperature, the rate of microbial
growth is temperature dependent.
Types of bacteria according to the temperature they grow.
Types of bacteria
Psychrophiles
Mesophiles
Thermophiles
Temperature Range for
growth
-7 -35 oC
7- 45 oC
40 -75 oC
Optimum temperature
20-30 oC
30-40 oC
45-60 oC
2. Gaseous environment
Oxygen and carbon dioxide are the principal gases in the cultivation of bacteria.
Types of bacteria according to their response to oxygen:
(1) Aerobic bacteria grow in the presence of free oxygen.
(2) Anaerobic bacteria grow in the absence of free oxygen.
(3) Facultative bacteria grow in either the absence or the presence of free
oxygen.
(4) Microphillic bacteria grow in the presence of minute quantities of free oxygen.
3. pH
optimum pH for growth for most bacteria: 6.5- 7.5
Few bacteria grow at extreme pH: pH 4- pH9
Methanogenic archaea, or methanogens, under anaerobic conditions are capable of
producing methane. Their habitats include:
deep-sea hydrothermal vents in the Pacific Ocean
hypersaline soda lakes in Siberia
wetlands/other natural sources~0.2 Gt of methane per year during 2008-2017.
rumen of cows/livestock grazing contributed another ~0.2 Gt per year
The highest recorded increase in atmospheric methane concentration occurred in 2021
at 1,895.7 parts per billion (ppb) from anthropogenic activities like the production of
fossil fuels and use; agriculture and waste and biomass and biofuel burning and natural
emissions from wetlands and swamps. Soil serve as sink for Methane produced from
atmospheric reactions.
Thermus aquaticus, found in the hot springs of Yellowstone, an Archaea bacteria from
which the enzyme Taq polymerase was isolated. This enzyme is heat-resistant crucial
for a DNA-amplification technique widely used in research and medical diagnostic(PCR
polymerase chair reaction. rT-PCR)
Spore formation. Some bacteria form spores as defense mechanism for their survival,
when subjected to extreme conditions like high temperature, radiation and toxic
chemicals. These spores live for years and may revert back to their normal cells or
become virulent. Spore forming bacteria are mostly found in soil.
Gram staining is used to differentiate bacteria into gram-positive and gram-negative.
Gram stain was developed by Hans Christian Gram in 1884. Gram staining procedure
is as follows:
1. Cover a smear of bacteria on a slide with the basic dye crystal violet. Wash off
the stain after 20 seconds. All cells are stained violet.
2. Cover the stained smear with Gram’s iodine solution and let stand for 1 minute.
Crystal violet will form complex with iodine within cells. All cells remain violet.
3. Flood the smear with 95% ethanol for 10-20 seconds and rinse the slide with
water. Gram-positive cells will remain violet, while gram-negative cells will be
colorless.
4. Cover the smear with safranin, a red counter stains, for 20 minutes then wash for
a few second and dry. Gram-positive cells remain violet while gram-negative will
become red.
A gram-negative bacteria like Eschericia coli, have an outer membrane
supported by a thin peptidoglycan layer in their cell walls. Severe diseases in
humans like meningitis, pneumonia, sepsis, UTI are cause by infection with
gram-negative bacteria such as Escherichia, Pseudomonas, Salmonella,
Enterobacter, Haemophilus, Shigella and Yersinia.
Gram positive cells do not have outer membrane. Instead, a multiple layers of
peptidoglycan make up their very thick, rigid cell wall. A typical gram-positive cell
is Bacillus subtilis.
Fungi
Fungi are plants devoid of chlorophyll, hence, cannot synthesize their own food. They
range in size and shape from single celled yeasts to multicellular mushrooms.
Yeasts are generally unicellular organisms and their shape is spherical to ovoid. They
have no chlorophyll, hence, depends on higher plants and animals for their energy.
Their size is 1-5 um in width and 5-30 um in length. Cell wall is thin and thicken with
age. They are found
(a) in fruits, grains and other food containing sugar
(b) in soil and in air
(c) skin and intestines of animals.
The growth pattern for yeast is budding, an asexual process, where small bud(daughter
cells) is formed on a mature cell. The bud grows and is filled with nuclear and
cytoplasmic material from the parent cell. When the bud is as large as the parent,
nuclear apparatus from each cells(parent and daughter) are reoriented and separation
follows.
Strains of Saccharomyces cerevisiae are the used in the manufacture of wine and beer
and in the leavening of bread, making them the most important yeasts.
Molds. Are filamentous fungi. A reproductive cell or spore(conidia) is germinated
To form a long thread, hyphae, which branches repeatedly as it forms mycelium, the
vegetative structure. The mycelium can grow indefinitely and attain macroscopic
dimensions. Molds are used in the production of antibiotics, industrial chemicals,
enzymes and food additives. The most important industrial classes of molds are
Aspergillus and Peniccillium.
Algae. they are eukaryotes capable of photosynthesis with chlorophyll as their primary
pigment but they lack other morphoanatomical true roots, stems, and leaves
characteristic/ features common among vascular plants. Some are unicellular while
others multicellular. Most algae are aquatic and others are terrestrial and may be found
in moist soil, trees and rocks. Some algal species form symbiotic relationship with other
organisms. For example, a lichen is a symbiotic association between fungi and green
algae.
Algae belong to a polyphyletic group, i.e., organisms in this group are not necessarily
closely related and do not have a common ancestor ,however, they share a common
feature; they are eukaryotes.
Blue-green algae are prokaryotes and therefore not considered as algae.
Importance
(1). Algae serve as food for aquatic animals. Some of them also live in symbiosis, such
as lichens. Lichen is a symbiotic association between algae and fungi in terrestrial
habitats. The presence of lichen could indicate the pollution status of the environment.
(2).Algae are used in different industries:
kelps (brown macroscopic algae) are harvested, dried, and processed for the
commercial production of soap, glass, etc. They are also used as fertilizers. They are
also used in the production of agar, growth medium in microbiological studies.
YOUTUBE: kelp farming
(3)Seaweeds are an important food source, and source of nutrients such as vitamins (A,
B1, B2, B6, niacin, and C), iodine, potassium, iron, magnesium, and calcium.
Macroalgae vs microalgae
Microalgae as potential good sources for biofuel production because of their relatively
high oil content and rapid biomass production. Microalgae grow very quickly compared
to terrestrial crops; the practice of algal mass culture can be performed on non-arable
lands using non-potable saline water and waste water. Thus, use of microalgae as an
alternative biodiesel biofuel feedstock is gaining increasing interest from researchers,
entrepreneurs, and the general public.
Viruses. Can do great harm but are also tools for potential good.
1. Are very small; sizes vary from 30 nm to 200 nm.
2. Obligate parasites of other cells such as bacterial, yeast, plant and animal cells.
3. Contain either DNA(DNA viruses) or RNA(RNA viruses) as genetic material.
4. In free-living cells, all genetic information is contained on the DNA, whereas
viruses can use either RNA or DNA to encode information.
5. Some viruses have an outer envelope of lipoproteins and some do not.
Viruses infecting bacteria are called bacteriophages.
1. Some bacteriophages have hexagonal head, tail and tail fibers.
2. Bacteriophages attach to the host cell with tail fibers, alter the cellwall of the host
cell and inject the viral nuclear material into the cell wall.
3. Bacteriophages nucleic acids reproduce in the host cells to produce more
phages.
Lytic cycle. During viral reproduction, host cells lyse or break apart and phage
particles are released, which can infect the host cells.
Lysogenic cycle. The phage DNA may be incorporated into the host DNA and the
host cell continue to multiply.
This Photo by Unknown Author is licensed under CC BY-SA
Viruses
1. Microbial fermentations such as lactic acid and acetone-butanol fermentation are
commonly contaminated by viruses. This explains the batch operation in
fermentation.
2. Polio virus in human.
In the Philippines, polio-related disease resurface in the third quarter of 2019
when a 3 year old girl from Mindanao was tested positive. The incidence broke
the 19 years polio free status in the Philippines.
Africa’s largest polio vaccination drive in 2020( amidst the China virus pandemic)
targeted 21M children.
NovelOPV2 rollout:
620 million doses administered across 29 counties under WHO
Emergency Use Listing(EUL)
Continued support from G7, World Health Assembly
3. Some viruses can be modified and used in genetic engineering. The modified
bacteriophages can be used as a vector(carrier) to incorporate foreign DNA to
host cell.
Viruses can do great harm but are also tools for potential good. (GMO)