Chapter 2 of Class 11 Biology is Biological Classification. It explains the five kingdom classification system devised by R.H. Whittaker and the distinguishing features of each kingdom. These Class 11 Biology Chapter 2 solutions are also useful as quick revision notes before exams.
Five Kingdom Classification
Proposed by R.H. Whittaker (1969), based on cell structure, thallus organization, mode of nutrition, reproduction, and phylogenetic relationships: Monera, Protista, Fungi, Plantae, and Animalia.
Kingdom Monera
Includes all prokaryotes (bacteria). Cell wall present but lacks a defined nucleus (no nuclear membrane). Classified by shape (bacillus, coccus, vibrio, spirillum) and nutrition mode (autotrophic/heterotrophic).
Kingdom Protista
Unicellular eukaryotes. Includes chrysophytes, dinoflagellates, euglenoids, slime moulds, and protozoans. Considered a link between plants, animals, and fungi.
Kingdom Fungi
Heterotrophic (mostly saprophytic), eukaryotic organisms with a cell wall made of chitin. Body organized as a network of filaments called hyphae, collectively forming a mycelium. Classes: Phycomycetes, Ascomycetes, Basidiomycetes, Deuteromycetes.
Viruses, Viroids, and Lichens
Viruses are non-cellular, obligate intracellular parasites (nucleic acid + protein coat) — not placed in the five kingdoms. Viroids are even simpler, consisting only of free RNA without a protein coat (discovered by Diener). Lichens are a symbiotic association between algae (or cyanobacteria) and fungi.
Class 11 Biology Chapter 2 – Notes and Extra Questions
Along with these NCERT Solutions, students can also use the Class 11 Biology Chapter 2 Extra Questions and Class 11 Biology Chapter 2 Revision Notes for quick revision and extra practice.
