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Biological Classification

NCERT Class 11 Biology Chapter 2

Biological Classification for Class 11 Biology and NEET: the five kingdoms, Monera, Protista and Fungi, and viruses, viroids, prions and lichens.

7 topics Updated 8 Nov 2026

For: Class 11 and NEET, unless a topic says otherwise

In the syllabus: NEET Class 11 syllabus

With your textbook

NCERT Biology (Class 11), Chapter 2 “Biological Classification”, reprint 2026-27.

Open the official NCERT chapter (PDF, 3.3 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Five kingdom classification

    Whittaker’s criteria, NCERT Table 2.1 compared, why two kingdoms failed, merits and demerits, and three domains.

    NEET only 10 min read 6 solved examples 12 practice questions

  2. Kingdom Monera

    Kingdom Monera for Class 11 Biology and NEET: characteristics, bacterial shapes with a diagram, archaebacteria vs eubacteria, cyanobacteria and mycoplasma.

    NCERT Section 2.1 9 min read 6 solved examples 12 practice questions

  3. Kingdom Protista

    Kingdom Protista for Class 11 Biology and NEET: diatoms, dinoflagellates, euglenoids with a labelled diagram, slime moulds and the four protozoan groups.

    NCERT Section 2.2 11 min read 6 solved examples 12 practice questions

  4. Kingdom Fungi

    Kingdom Fungi for Class 11 Biology and NEET: hyphae, nutrition, sexual cycle and dikaryon, and phycomycetes, ascomycetes, basidiomycetes, deuteromycetes.

    NCERT Section 2.3 10 min read 6 solved examples 12 practice questions

  5. Kingdom Plantae

    Kingdom Plantae for Class 11 Biology and NEET: plant features, partial heterotrophs, the five plant groups and alternation of generations with a diagram.

    NCERT Section 2.4 7 min read 6 solved examples 12 practice questions

  6. Kingdom Animalia

    Characteristics of animals, holozoic nutrition, glycogen and fat reserves, and how animals differ from plants.

    NCERT Section 2.5 7 min read 6 solved examples 12 practice questions

  7. Viruses, viroids, prions and lichens

    Virus structure with labelled TMV and bacteriophage diagrams, viroids vs prions, and lichens.

    NCERT Section 2.6 11 min read 6 solved examples 12 practice questions

Key formulas in this chapter

Five kingdom classification

  • five kingdoms: Monera, Protista, Fungi, Plantae, Animalia (Whittaker, 1969)
  • criteria: cell structure, body organisation, nutrition, reproduction, phylogeny
  • prokaryotic: Monera only
  • cell wall: chitin in Fungi, cellulose in Plantae, none in Animalia
  • NCERT mapping: Monera split in two + 4 eukaryotic kingdoms = six kingdoms

Kingdom Monera

  • Monera: prokaryotic, only bacteria
  • shapes: coccus, bacillus, vibrio, spirillum
  • archaebacteria: halophiles, thermoacidophiles, methanogens
  • cyanobacteria: chlorophyll a; some fix N in heterocysts
  • fission: multiplication; endospores: survival; DNA transfer: variation
  • mycoplasmas: no cell wall; NCERT’s smallest-cell example

Kingdom Protista

  • Protista: single-celled eukaryotes
  • diatoms: two overlapping silica shells (soap box)
  • dinoflagellates: cellulose plates; red tides
  • euglenoids: pellicle, two flagella, plant pigments
  • slime moulds: saprophytic; plasmodium; resistant spores
  • protozoans: amoeboid, flagellated, ciliated, sporozoans

Kingdom Fungi

  • fungi: heterotrophic; walls of chitin and polysaccharides
  • sexual cycle: plasmogamy → karyogamy → meiosis
  • dikaryon (n + n): ascomycetes and basidiomycetes
  • phycomycetes: aseptate, coenocytic; zygospore
  • ascomycetes: conidia (exogenous), ascospores in asci
  • basidiomycetes: four basidiospores on a basidium
  • deuteromycetes: only conidia known

Kingdom Plantae

  • Plantae: eukaryotic, mostly photosynthetic, cellulose-rich walls
  • groups: algae, bryophytes, pteridophytes, gymnosperms, angiosperms
  • nutritional exceptions: insectivorous plants and parasites
  • sporophyte 2n → meiosis → spores n → gametophyte n
  • gametes n + n → zygote 2n → sporophyte

Kingdom Animalia

  • Animalia: heterotrophic, eukaryotic, multicellular, no cell wall
  • usual nutrition: holozoic, by ingestion; exceptions occur
  • reserves: glycogen or fat
  • definite growth pattern, shape and size
  • sexual reproduction: gamete fusion, then embryological development

Viruses, viroids, prions and lichens

  • virus: protein capsid + an RNA or DNA genome
  • plant viruses: usually ssRNA; bacteriophages: usually dsDNA
  • viroid: free RNA, no protein coat
  • prion: abnormally folded protein
  • lichen: phycobiont (alga) + mycobiont (fungus)

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