Biological Classification

SHORT NOTES
Table 1: Characteristics of Five Kingdoms proposed by Whittaker (1969)

Five Kingdoms
Characters
Monera Protista Fungi Plantae Animalia
Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic
Cell wall Noncellulosic (Polysaccharide Present in some Present with chitin Present (cellulose) Absent
+ amino acid)
Nuclear membrane Absent Present Present Present Present
Body organisation Cellular Cellular Multicellular/ Tissue/organ Tissue/organ/
loose tissue organ system
Mode of nutrition Autotrophic (Chemosynthetic Autotrophic Heterotrophic Autotrophic Heterotrophic
and photosynthetic) and (Photosynthetic) (Saprophytic/ (Photosyn-thetic) (Holozoic/
Heterotrophic (sapro-phytic/ and Hetero- Parasitic) Saprophytic etc.)
parasitic) trophic

Kingdom Monera Archaebacteria

™ Has bacteria a sole member. ™ Halophiles (salt-loving)
™ Bacteria can have shapes like: Coccus (sphere cal). Bacillus (rod- ™ Thermoacidophiles (in hot springs)
shaped). Vibrio (comma shaped) and sprillum (spiral shaped) ™ Methonogens (in marsh and in gut of ruminant animals
™ Bacteria found almost everywhere and can he Photosynthetic produce methane gas.)
autotrophs, Chemosynthetic autotrophs or Heterotrophs.

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Eubacteria (iii) Euglenoids: Have protein rich layer 'pellicle' which makes
Photosynthetic autotrophs like Cyanobacteria. some like
™
body flexible. Photsynthetic in presence of sunlight but become
Anabaena have specialised cells called heterocysts for heterotrophs if they do not get sunlight.
nitrogen fixation. (iv) Slime Moulds: Saprophytic protists form aggregates to form
™ Chemosynthetic autotrophs: Oxidise various inorganic plasmodium grows on decaying twigs and leaves. Spores have
substances like nitrates/nitrites, ammonia and use released true walls which are extremely resistant and survive form many
energy for their ATP production. years.
™ Heterotrophic bacteria: decomposes, help in making curd, (v) Protozonans:
production of antibio tics, N2 fixation, cause diseases like ™ Amocboid: Catch prey using pseudopdia, e.g., Amoeba.
cholera, typhoid. ™ Flagellated: More flagella. Cause disease like sleeping
Mycoplasma: Completely lack cell wall. smallest living cells. sickness e.g., Trypanosoma.
Can survive without oxygen. Pathogenic in animals and plants.
™ Ciliated: Have cilia to move food into gullet and help in
Kingdom Prostita: (All single celled eukaryotes) locomation. e.g., Paramecium.
Forms a link between plants, animals and fungi. ™ Sprozonans: Have infective spore like stage in life cycle,
(i) Chrysophytes: (Has diatoms and golden algae) e.g., Plasmodium which causes

™ Cell walls have silica and cell walls overlap to fit together Kingdom Fungi
like a soap box. ™ Non chlorophyllous hyphae
™ Their accumulation forms 'Diatomaceous Earth'. ™ Network of hyphane called mycelium
™ Used in polishing, filtration of oils and syrups. ™ Cell wall of chitin and polysaccharides
(ii) Dinoflagellates: Marine, photosynthetic, cell wall has ™ Grow in warm and humid places
cellulose. Two flagella "one longitudinal and other transversely in ™ Saprophytic, parasitic, symbiotic (Lichen) e.g., Puccinia
a furrow between wall plates. (rust causing), Penicillium.

Table 2: Characteristics of Four Classes of fungi

Classes Typical Examples Sexual Reproduction Asexual Reproduction Hyphae
Phycomyeetes Rhizopus, Mucor, Albugo Zygospores Zoopores (motile) Aseptate and
Aplanospores (non-motile) Coenocytic
Ascomyeetes (Sac Penicillium (multicellualr), Ascospores produced Conidia produced on Branched and septate
fungi) yeast (unicellualr), Aspergillus, endogenously in sac conidiophore
Claviceps, Neurospora, morels like asci
and truffles (buffles)
Basidiomyeetes Mushrooms (Agaricus) smut Basidiospores Generally asexual spores Branched and septate
(Club fungi) (Ustilago), Rust (Puccinia) produce exogenously are not found bu reproduce
Bracket fungi or Puff balls. on the basidium vegetatively by fragmentation
Deuteromyeetes Alternaria, Colletotrichum. Sexual phase has not Conidia Branched and
(Imperfect fungi) Trichoderma been observed Septate

Classes of Fungi ™ Sexual spores are called ascspores produced endog enously
(i) Phycomycetes: in ascus produced inside fruiting body called ascocarp. e.g.,
Aspergillus, Neurospora.
™ Grow on decaying wood
(iii) Basidiomycetes:
™ Mycelium Aseptate
™ Mycelium septate.
™ spores produced endgogenously
™ The asexual spores are generally not found but vegetative
™ Asexual reproduction by Zoospores of Aplanospores e.g.,
Rhizopus, Albugo. reproduction by fragmentation is common.
(ii) Ascomycetes: ™ The basidiospores are exogenously produced on the basidium
(pl.:basidial).
™ Also known as 'sac fungi'
™ The basidia are arranged in fruiting bodies called basidiocarps.
™ Mycelium branched and septate
™ Some common members are Agaricus (mushroom), Ustilago
™ Spores: Asexual spres are called conidia produced
(smut) and Puccinia (rust fungus).
exogenously on the conidiophores.

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(iv) Deuteromycetes: Structure of Virus
™ Called as 'Fungi imperfecti' as sexual form(perfect stage) is ™ Its a nucleoprotein Covered by protein called Capsid. Capsid
not known for them. is made up of capsomeres arranged in helical or polygeometric
™ Once perfect (sexual) stages of members of dueteromycetes forms.
were discovered they were often moved to ascomycetes and ™ Have either DNA or RNA as genetic material which may be

basidiomycetes. single or double stranded.

™ Usually plant viruses have single stranded RNA
™ The deuteromycetes reproduce only by asexual spores known
™ Bacteriophages have double stranded DNA and animal virus
as conidia.
have single or double stranded RNA or double stranded DNA.
™ The mycelium is septate and branched.
Diseases caused: Mumps, Small pox, AIDA etc.
™ Some members are saprophytes or parasites while a large
Viroids
number of them are decomposers of litter and help in mineral
™ Infectious agent, free RNA (lack protein coat) of low
cycling. molecular weight
™ Some examples are Alternaria, Colletotrichum and Trichoderma. ™ Causes potato spindle tuber disease.
™ Discovered by T.O. Diener.
Viruses
Prions
™ They did not find a place i classification. Take over the machinery
™ They consist of abnormally folded protein without genetic
of host cell on entering it but as such they have inert crystalline
material.
structure. So, difficult it call them living or non-living.
™ They cause mad cow disease in cattle and
™ Pasteur gave the term 'Virus' i.e., poisonous fluid. Cr–Jacob disease (CJD) in humans.
™ D.J. Ivanowsky found out that certain microbes cause Lichens
™ M.W. Beijerinek called fluid as 'Contagium vivum fluidum' ™ Symbiotic association between algal component (Phycobiont)
as extracts of infected plants of tobacco could cause infection and fungal component (mycobiont). Algae provide food.
in healthy plants. Fungi provide shelter and absorb nutrients for alga.
™ W.M. Stanely showed viruses could be arystalli sed to ™ Good pollution indicators as they do not grow in polluted area.
form cry stals of protein which are inert outside their ™ Mycorrhiza: Symbiotic association between fungi and roots of
specific host. higher plants.