NCERT Solutions for Class 11 Biology Chapter 4

NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom to Study online as well as available to download in PDF form free. Download NCERT Solutions based on latest and updated NCERT Books for CBSE course.


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Animal Kingdom: Solutions




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NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom
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Important Terms on Animal Kingdom

  • Asymmetrical: Cannot be divided into equal halves through median plane e.g., Sponges.
    Radial symmetry: Any plane passing through central axis can divide organism into identical halves. e.g., coelentrates,Ctenophores and echinoderms.
  • Bilateral symmetry: Only one plane can divide the organism into two identical left and right halves e.g., Annelids and Arthropods.
  1. Coelom (Body cavity which is lined by mesoderm)
  2. Coelomates: Have coelom e.g., Annelids, Arthropods, molluscs, Echinoderms, Chordates etc.
  3. Pseudocoelomates: No true coelem as mesoderm is present in scattered pouches between ectoderm and endoderm. e.,g., Aschelminthes.
  4. Acoelomates: Body cavity is absent e.g., Platyhelminthes.



  • Metamerism: If body is externally and internally divided into segments (metameres) with serial repetition of atleast some organs, then phenomenon is called metamerism e.g., Earthworm.
  • Pseudometamerism: Found in tapeworm. The proglottids (segments of tapeworm) budded off from neck not emryonic in origin.
  • Notochord: Rod-like structure formed during embryonic development on t he dorsal side. It is mesodermally derived e.g., Chordates. Non-chordates do not have notochord .e.g., porifera to echinoderms.



Phylum Ctenophora
  • Also called as sea walnuts or comb jellies.
  • Are exclusively marine, radially symmetrical.
  • Have tissue level organisation, are diploblastic.
  • Digestion both extra and intracellular.
  • Body has eight external rows of ciliated comb plates for locomotion.
  • Show Bioluminescence (Property of living organisms to emit light).
  • Hermaphrodite (sexes are not separate).
  • Only sexual reproduction occurs. Exernal fertilization. Indirect development. e.g., Ctenoplana, Pleurobrachia.



Phyum Annelida
  1. Are aquatic or terrestrial, free-living or parasitic.
  2. Are bilaterally symmetrical, triploblastic, organ-system level of organisation and metamerically segmented body.
  3. Are coelomate animals.
  4. Have longitudinal and circular muscles for locomation.
  5. Have closed circulatory system.
  6. Nereis (dioecious and aquatic annelid) has lateral appendages called parapodia for swimming.
  7. Have nephridia for osmoregulation and excretion.
  8. Neural system consists of paired gangila connected by lateral nerves to a double ventral nerve cord.
  9. Reproduction is sexual. e.g., Earthworm (Pheretima) and Leech (Hirudinaria) which are hermaph rodites (i.e., monoecious).