(i) R.H.Whittaker, an American taxonomist proposed five kingdom classification in the year 1969.
(ii) The Kingdoms include Monera, Protista, Fungi, Plantae and Animalia.
(iii) The criteria adopted for the classification include cell structure, thallus organization, mode of nutrition, reproduction and phylogenetic relationship. The merits and demerits are as follows:
Merits:
(i) The classification is based on the complexity of cell structure and organization of thallus.
(ii) It is based on the mode of nutrition.
(iii) Separation of fungi from plants.
(iv) It shows the phylogeny of the organisms.
Demerits:
(i) The kingdom Monera and Protista accommodate both autotrophic and heterotrophic organisms, cell wall lacking and cell wall bearing organisms thus making these two groups more heterogeneous.
(ii) Viruses were not included in the system.
 

(i) Sexual reproduction is present but sex organs are absent. Somatogamy or spermatisation results in plasmogamy.
(ii) Karyogamy is delayed and dikaryotic phase is prolonged.
(iii) Karyogamy takes place in basidium and it is immediately followed by meiotic division.

Plant diseases:
(i) Tobacco mosaic
(ii) Cauliflower mosaic
(iii) Sugarcane mosaic.
Animal diseases:
(i) Foot and mouth disease of cattle
(ii) Rabies of dog
(iii) Encephalomyelitis of horse
Human diseases:
(i) Common cold
(ii) Hepatitis B
(iii) Cancer

Different Classes of viruses
Class	Example
Class 1 - Viruses with dsDNA	Adenoviruses
Class 2 - Viruses with (+) sense ssDNA	Parvo viruses
Class 3 - Viruses with dsRNA	Reo viruses
Class 4 - Viruses with (+) sense ssRNA	Toga viruses
Class 5 - Viruses with (-) antisense ssRNA	Rhabdo viruses
Class 6 - Viruses with (+) sense ss RNA - RT that replicate with DNA intermediate in life cycle	Retro viruses
Class 7 - Viruses with ds DNA - RT that replicate with RNA intermediate in life cycle	Hepadna viruses

1. Lichens are the pioneer organisms in the new terrains which colonise bare rocks, mountains and cliffs.
2. They corrode the rocks and accumulate a certain amount of minerals and organic matter.
3. The plants like mosses and grasses appear later in succession, utilizing the first soil formed by lichens.
4. Lichens thus, can convert a barren area into one that can support vegetation.

Importance of Mycorrhizae:
1. Mycorrhizae helps to derive nutrition in Monotropa, a saprophytic angiosperm.
2. Improves the availability of minerals and water to the plants.
3. Provides drought resistance to the plants.
4. Protects roots of higher plants from the attack of plant pathogens.

1. The bacteria which become decolourised and appear in red colour in Gram's staining procedure are called as Gram -ve.
2. Eg: E.coli, Salmonella.

1. Pili or Fimbriae are hair like appendages found Discuss. on surface of cell wall of gram-negative bacteria.
Eg: Enterobacterium.
2. The pili are 0.2 to 20 11m long with a diameter of about 250A
3. In addition to normal pili there are special type of pili which help in conjugation called sex pili are also found.

S.No.	Bacteria	Role
1.	Streptococcus lactis and Lactobacillus bulgaricus.	Making curd (Convert milk sugar lactose into lactic acid).
2.	Lactobacillus lactis	Used in making cheese.
3.	Streptococcus lactis.	Used in curd and making butter

Animal diseases
S.No	Name of the Animal	Name of the diseases	Name of the pathogen
1.	Sheep	Anthrax	Bacillus anthracis
2.	Cattle	Brucellosis	Brucella abortus
3.	Cattle	Bovine tuberculosis	Mycobacterium bovis
4.	Cattle	Blackleg	Clostridium chanvoei