Molluscs

SEO Title: Molluscs: Classification, Characteristics, Examples and Importance for UPSC Biology

Category: Environment & Ecology | Zoology | Biodiversity

UPSC Notes

Mollusca is a large phylum of invertebrate animals that includes snails, slugs, oysters, clams, mussels, squids, octopuses and cuttlefish.

Key Pointers

  • Mostly soft-bodied animals.

  • Many have a protective calcareous shell.

  • Major classes:

    • Gastropoda → snails, slugs

    • Bivalvia → clams, oysters, mussels

    • Cephalopoda → octopus, squid, cuttlefish

    • Polyplacophora → chitons

  • Radula is a characteristic feeding structure in many molluscs.

  • Cephalopods are highly developed marine molluscs.

  • Octopus and squid possess sophisticated nervous systems.

  • Molluscs have major ecological and economic importance.

  • Some species act as indicators of aquatic ecosystem health.

Prelims Focus: Mollusca → soft body → shell → radula → Gastropoda/Bivalvia/Cephalopoda.