Q88. Identify the phylum that is characterized by the animals that have segmented appendages.
- Cnidaria
- Porifera
- Arthropoda
- Mollusca
Animals with segmented appendages belong to a major invertebrate phylum featuring jointed limbs adapted for locomotion, feeding, and sensing. Segmentation allows specialized body regions and flexible movement. This trait defines a highly successful group dominating terrestrial and aquatic habitats.
Correct Answer
Arthropoda is the phylum characterized by animals that have segmented appendages.
These include insects, spiders, crustaceans, and myriapods with jointed (arthropod = “jointed foot”) appendages on segmented bodies.
Appendages like legs, antennae, and mouthparts arise from somites and diversify through tagmosis (fusion into tagmata like head, thorax, abdomen).Option Analysis
Cnidaria
Cnidarians like jellyfish and corals have radial symmetry and simple body plans with tentacles, not segmented appendages.
They lack segmentation entirely, using cnidocytes for prey capture instead of jointed limbs.
Marine, mostly sessile or drifting forms.Porifera
Sponges (Porifera) are the most primitive metazoans without true tissues, organs, or appendages.
Sessile filter-feeders with porous bodies and choanocytes; no segmentation or mobility structures.
Aquatic, asymmetrical.Arthropoda (Correct)
Over a million species with chitinous exoskeleton, open circulation, and ventral nerve cord.
Segmentation visible in embryos; appendages on most segments for diverse functions.
Includes insects (flight), crabs (swimming), spiders (silk).Mollusca
Mollusks like snails, squids, and clams have unsegmented, soft bodies with muscular foot or tentacles.
No jointed appendages; locomotion via foot gliding or jet propulsion in cephalopods.
Include bivalves, gastropods, cephalopods.Option Segmented Appendages? Key Body Features Examples Cnidaria No Radial symmetry, tentacles Jellyfish, anemones Porifera No Porous, no tissues Sponges Arthropoda Yes Jointed limbs, exoskeleton Insects, crabs, spiders Mollusca No Muscular foot, mantle Snails, octopuses, clams This phylum’s segmentation and appendages enable ecological dominance and evolutionary success across environments.
