Aristotle was a first person who tried to classify plant and animals on scientific basis. He use simple morphological character(shape, size, colour etc. called morphological characters) to classify plant into herbs, shrubs and trees. He also classify animals into 2, have red blood cells(enaima) and have without red blood cells(anaima).

Two Kingdom System of Classification have Kingdom Plantae(plants) and Kingdom Animalia(animals) respectively. But there are such limitations or demerits are- this system does not distinguish between eukaryotes and prokaryotes, unicellular and multicellular organisms, photosynthetic and non-photosynthetic organisms. This system easy to understand but there are many different organisms come in same category, so after some time this system found inadequate.

Then three kingdom, four kingdom, five kingdom and six kingdom classification system are found, but Five Kingdom System of Classification used today too.

FIVE KINGDOM SYSTEM OF CLASSIFICATION-

This system is proposed by R.H. Whittaker in 1969. The name of this 5 kingdoms are- Monera, Protista, Fungi, Plantae, Animalia. The main criteria for classification used by him is cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationship.

KINGDOM- MONERA

All bacteria are present in kingdom Monera. Bacteria are most abundant microorganisms and it present almost everywhere. Bacteria can also live and survive in very extreme habitat such as hot spring, deep ocean, in snow, in desert etc. where a very few life form survive. Bacteria are grouped based on their shape.*take photo of bacteria*

  1. Archaebacteria-These bacteria can survive in most harsh habitats like hot-spring(those bacteria can survive in hot areas called thermoacidophiles), salty areas(called halophiles), and marshy areas(called methanogens). Archaebacteria are special and different from other bacteria because it has different cell wall structure and this feature responsible for survive in extreme habitat. methanogens are present in gut of ruminant animals(cow, buffaloes) and responsible for production of biogas(methane) from the dung of these animals.
  2. Eubacteria or true bacteria– They are single-celled organisms without a nucleus and it include common bacteria. The cyanobacteria(also called blue-green algae) come under eubacteria and it have chlorophyll a just like green plant and cyanobacteria are photosynthetic autotrophs. The cyanobacteria are unicellular, colonial / filamentous, and found in fresh, marine water and terrestrial algae too. These colonies are surrounded by gelatinous sheath. Some organisms can fix the atmospheric nitrogen in specialised cell called heterocysts. The majority of bacteria are decomposers. Also bacteria are helpful in formation of curd, production of antibiotics, nitrogen fixing, etc. Also some bacteria are pathogens(disease causing bacteria), damage crops and harm to farm animals etc. Some dangerous disease like cholera, typhoid, citrus canker, tetanus etc. are some disease cause by bacteria. Bacteria can reproduce by fission, spore formation, and also reproduce by sort of sexual reproduction by transfer primitive type of DNA form one cell to another. Mycoplasma have no cell wall. Mycoplasma are the smallest living cell and it can survive without oxygen. Some mycoplasma are pathogenic in plants and animals.

KINGDOM- PROTISTA

All the single-celled eukaryotes are present in kingdom Protista but boundaries of this kingdom is not well defined. Member of protista are primary aquatic. All the kingdom are originate from this kingdom. Member of protista have cilia or flagella for movement. Protista reproduce sexually and asexually. Kingdom Protista include Chrysophytes, Dinoflagellates, Euglenoid, Slime Moulds and Protozoan.

  1. Chrysophytes- They are found in aquatic(both fresh and marine water) habitat. They are microscopic and float passively on flowing water(plankton). Some of these are photosynthetic. Chrysophytes has 2 types- Diatoms and Golden algae(desmids). In Diatoms, the cell well form 2 overlapping shells which fit together and look like a soapbox. Diatoms are also called chief producer in oceans.
  2. Dinoflagellates– They prepared food by photosynthetic method and mostly found in marine water(salty water). The Dinoflagellates have different colour and these colour are based on main pigment of cell. Most have 2 flagella. Most popular is red dinoflagellate(eg.- Gonyaulax) and also sea seen red by red dinoflagellate. They release toxin in sea which kill many marines animals.
  3. Euglenoid- They are found in fresh water. It has a protein rich layer called pellicle and it make its body flexible. It has 2 flagella. It behave like both photosynthetic(when it contact of sunlight) and heterotrophs(when it comes in dark region) organisms. ex-euglena.
  4. Slime Moulds- They are saprophytic organisms. Its body moves along decaying and leaves engulfing material. In favourable condition, it form plasmodium. In unfavourable condition, the plasmodium differentiate and form a fruiting bodies.
  5. Protozoans- They are heterotrophs and live as a parasite(attached on other organisms).Protozoan has 4 types-
  1. Amoeboid protozoan- They are found in fresh, marine water or in moist soil. They can move for capture food by putting out pseudopodia(false feet).
  2. Flagellated protozoan- They can free living or as parasitic. They have flagella which help in locomotion. It cause a disease called sleeping sickness. ex-Trypanosoma.
  3. Ciliated protozoan- They are found in fresh water and marine water. They can move actively because it have 1000s of cilia. ex.-Paramoecium.
  4. Sporozoan- It cause malaria which effect human population.

KINGDOM- FUNGI–

All the members of kingdom fungi is heterotrophs. All fungi are multicellular except yeast(unicellular fungi). Fungi are seen in moist bread, rotten fruits, on bear etc. Fungi are cosmopolitan and found in air, water, soil, on plant and animals(bear). Fungi prefer to grow in moist and humid places. And fungi help in making bread, beer, antibiotics(penicillium), etc. Also fungi cause diseases in plant(rust-causing disease called Puccinia) and animals.

The body of fungi is has long, thread like structure called hyphae and the network of hyphae called mycelium. Some hyphae are continuously tubes fill with multinucleated cytoplasm, called coenocytic. The cell wall of fungi is made up of chitin and polysaccharides. Fungi make beneficial association with algae as lichen and root of higher plant as mycorrhiza called symbionts. Symbiotic association is a close, long-term interaction between two different species, benefiting one or both.

The reproduction in fungi take place by sexual, asexual and vegetative method respectively. Vegetative reproduction by fragmentation, fission and budding. Asexual reproduction occur by spores called zoospores or conidia. The sexual reproduction in fungi take place by oospores, ascospores and basidiospores. These spores produced a different structure called fruiting bodies.

The sexual cycle of fungi has 3 steps-

  1. Plasmogamy- The fusion in between 2 motile and non-motile gametes of protoplasm.
  2. Karyogamy- Fusion of 2 nuclei.
  3. Meiosis process in zygote, then haploid spores formed.

Kingdom fungi are divided into 4 classes-

  1. Phycomycetes-
  • Habitat-Found in aquatic habitat, in moist region(like decaying wood) and as a parasites on plant .
  • Mycelium- Septate and coenocytic.
  • Reproduction- Asexual reproduction, take place by zoospores(motile) or by aplanospores(non-motile) which produced in sporangium. The zygospore is formed by fusion of 2 gametes. These gametes are similar(isogamous) or dissimilar(anisogamous, oogamous).
  • Examples- Mucor, Rhizopus(on bread), Albugo(parasitic fungus) etc.

2. Ascomycetes(sac fungi)-

  • Habitat- Found in dead and decaying i.e. saprophytes, decomposers and parasitic.
  • Mycelium- Branched and septate.
  • Reproduction- By sexual and asexual method- Sexual reproduction occur by spores called ascospores which produced sac like asci(singular ascus) which arranged in different types called fruiting bodies. Asexual reproduction by spores are conidia which produced on special mycelium called conidiophores.
  • Examples- Aspergillus, Claviceps, Neurospora(used in biochemical and genetic work), Yeast(unicellular), Penicillium(multicellular) etc.

3. Basidiomycetes(also called mushrooms, bracket fungi or puffball)-

  • Habitat- Found in soil, tree stumps, parasite on plants.
  • Mycelium- Branched and septate.
  • Reproduction- Vegetative by fragmentation and some time sexual reproduction occur.
  • Examples- Agaricus(mushrooms), Ustilago(smut), Puccinia(rust fungus).

4. Deuteromycetes(also called imperfect fungi)-

  • Habitat- Found as a parasitic, they are decomposers.
  • Mycelium- Septate and branched.
  • Reproduction- Only vegetative and sexual stage are known, that is why called imperfect fungi. It reproduced by only sexual spores called conidia.
  • Examples- Alternaria, Colletotrichum and Trichoderma.

KINGDOM PLANTAE-

It is a kingdom of eukaryotic chlorophyll containing, multicellular organisms commonly called plants. They are heterotrophic and parasite. It cell wall mainly composed of cellulose. Life cycle of plants has 2 phases- diploid sporophytic and haploid gametophytic. Length of these phases depend on plants, this phenomenon is called alternation of generation. Kingdom plantae includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms.

KINGDOM ANIMALIA-

It is a kingdom of heterotrophic eukaryotes and multicellular organisms which lack of cell wall is commonly called animals. The all are depend on plants for food. They digest in internal cavity and store food in form fat or glycogen. They follow holozoic(by ingestion of food) mode of nutrition. They follow definite growth pattern. They are mostly capable for locomotion. They reproduced sexually by copulation of male and female and follow embryological development.

In five kingdom system of classification of R.H. Whittaker, he does not mention about Viruses, Viroids, Prion and Lichens.

VIRUSES-

It is discovered by Dimitri Ivanowsky in 1892. Virus are non-cellular organization. It has inner crystalline structure out side the living cell. Virus means poisonous fluid. Virus contain genetic material which either be DNA or RNA. A virus is nucleoprotein and genetic material is harmful. Virus have protein coat called capsid which made of small subunits called capsomeres, it protect the nucleic acid. Virus cause many diseases like AIDS in humans, leaf rolling and curling in plants.

VIROIDS-

It is discover by T.O. Diener in 1971. It is smaller than virus. It is RNA free organisms and RNA has low molecular weight. It also lack protein coat which found in viruses. It cause potato spindle tuber disease.

PRIONS-

It is similar to viruses. It cause most notable disease like bovine spongiform encephalopathy(BSE) commonly called mad cow and cause Cr-Jacob disease(CJD) in humans.

LICHENS-

It make a symbiotic association(mutually useful association) between algae(algal component as phycobiont) and fungi(fungal component called mycobiont. They are heterotrophic. Algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients and water for its partner, i.e. fungi. Lichen grow in fresh water(means pollution indicator).

These all are the notes of chapter 2 in biology. And important questions are below HERE. *#THANKS FOR VISITING, VISIT AGAIN#* 😊

1. Who was the first person to classify plants and animals scientifically?

  • Answer: Aristotle was the first person to classify plants and animals scientifically.

2. How did Aristotle classify plants?

  • Answer: Aristotle classified plants into three categories based on their shape and size:
    • Herbs
    • Shrubs
    • Trees

3. How did Aristotle classify animals?

  • Answer: Aristotle classified animals into two groups:
    • Animals with red blood (enaima)
    • Animals without red blood (anaima)

4. What are the limitations of the Two Kingdom System of Classification?

  • Answer: The Two Kingdom System does not distinguish between:
    • Prokaryotes and eukaryotes.
    • Unicellular and multicellular organisms.
    • Photosynthetic and non-photosynthetic organisms.

5. Who proposed the Five Kingdom Classification, and when?

  • Answer: R.H. Whittaker proposed the Five Kingdom Classification in 1969.

6. What are the five kingdoms in the Five Kingdom Classification?

  • Answer: The five kingdoms are:
    1. Monera
    2. Protista
    3. Fungi
    4. Plantae
    5. Animalia

7. What is the main criterion for classification in the Five Kingdom System?

  • Answer: The main criteria are:
    • Cell structure
    • Body organization
    • Mode of nutrition
    • Reproduction
    • Phylogenetic relationship (evolutionary history)

8. What are the two main groups of bacteria in the Kingdom Monera?

  • Answer: The two main groups are:
    1. Archaebacteria: Survive in extreme conditions (hot springs, salty areas, marshes).
    2. Eubacteria: True bacteria, including cyanobacteria (photosynthetic).

9. What is special about Archaebacteria?

  • Answer: Archaebacteria have a unique cell wall structure that helps them survive in extreme environments.

10. What are the features of cyanobacteria (blue-green algae)?

  • Answer:
    • Photosynthetic autotrophs.
    • Contain chlorophyll like green plants.
    • Found in freshwater, marine, and terrestrial habitats.
    • Some fix atmospheric nitrogen using specialized cells called heterocysts.

11. What is Mycoplasma, and why is it unique?

  • Answer:
    • Mycoplasma are the smallest living cells.
    • They lack a cell wall.
    • They can survive without oxygen.

12. What is Kingdom Protista?

  • Answer:
    • Kingdom Protista includes single-celled eukaryotes.
    • They live in water and reproduce sexually or asexually.
    • Examples: Chrysophytes, Dinoflagellates, Euglenoids, Slime Molds, and Protozoans.

13. What are Protozoans?

  • Answer:
    • Protozoans are single-celled heterotrophs that can live as parasites or independently.
    • Types:
      • Amoeboid (e.g., Amoeba)
      • Flagellated (e.g., Trypanosoma, causes sleeping sickness)
      • Ciliated (e.g., Paramecium)
      • Sporozoan (e.g., Plasmodium, causes malaria)

14. What is Kingdom Fungi?

  • Answer:
    • Fungi are heterotrophs (decomposers or parasites).
    • Most are multicellular (except yeast, which is unicellular).
    • Examples: Mushrooms, Yeast, Penicillium.
    • Fungi reproduce sexually, asexually, and vegetatively.

15. What is lichen?

  • Answer:
    • Lichen is a symbiotic association between algae and fungi.
    • Algae make food, and fungi provide water and shelter.

16. What is the main characteristic of Kingdom Plantae?

  • Answer:
    • Kingdom Plantae includes multicellular organisms with chlorophyll.
    • They are autotrophs (make their own food) and have cell walls made of cellulose.

17. What is the main characteristic of Kingdom Animalia?

  • Answer:
    • Kingdom Animalia includes multicellular, heterotrophic organisms without cell walls.
    • They reproduce sexually and show locomotion.

18. Why are viruses not included in the Five Kingdom Classification?

  • Answer:
    • Viruses are non-cellular organisms.
    • They cannot reproduce without a host.
    • They have either DNA or RNA but not both.

19. What are viroids?

  • Answer:
    • Viroids are smaller than viruses.
    • They consist of RNA without a protein coat.

20. What are prions?

  • Answer:
    • Prions are infectious proteins.
    • They cause diseases like mad cow disease and Creutzfeldt-Jakob disease.