NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification

Short Note:

• R.H. Whittaker (1969) proposed five kingdoms based on cell structure, mode of nutrition, body organisation, and phylogenetic relationships: Monera, Protista, Fungi, Plantae, and Animalia.

Short Note:

• Monera includes all prokaryotes (bacteria), which lack a true nucleus and membrane-bound organelles; further classified based on cell wall, motility, and nutrition (archaebacteria, eubacteria).

• Protista includes unicellular eukaryotic organisms, such as chrysophytes, dinoflagellates, euglenoids, slime moulds, and protozoans.

Short Note:

• Fungi are eukaryotic, heterotrophic (saprophytic) organisms with a cell wall made of chitin; body is generally made of thread-like structures called hyphae, collectively forming a mycelium.

• Classified into Phycomycetes, Ascomycetes, Basidiomycetes, and Deuteromycetes based on the mode of spore formation.

Short Note:

• Viruses are non-cellular, obligate intracellular parasites, composed of genetic material (DNA or RNA) surrounded by a protein coat (capsid); they are inert outside a living host.

• Viroids (discovered by T.O. Diener) are smaller than viruses and consist only of free RNA, without a protein coat.

• Lichens are a symbiotic association between algae (phycobiont, provides food) and fungi (mycobiont, provides shelter and absorption).