Which feature is characteristic of Porifera?

Which feature is characteristic of Porifera?

• A. Spicules
• B. Segmented Bodies
• C. Jointed Limbs
• D. Chitinous Exoskeleton

Answer: (A)

Sponges (Porifera) are simple, sessile animals that lack true tissues and organs. A defining feature is their internal skeleton made of spicules (mineral needles made of silica or calcium carbonate) or, in some species, a fibrous network of a protein called spongin. This skeletal support gives shape and rigidity to the sponge as it functions as a filter feeder, drawing water through its porous body to capture micro–organisms. Because spicules are a distinctive, structural trait of sponges, they stand out as the characteristic feature among the options. The other possibilities describe features of different animal groups—segmented bodies, jointed limbs, and chitinous exoskeletons are associated with arthropods and related lineages—not with Porifera, which do not have tissues or organs and rely on their spicule- or spongin-based skeleton for support.

Sponges (Porifera) are simple, sessile animals that lack true tissues and organs. A defining feature is their internal skeleton made of spicules (mineral needles made of silica or calcium carbonate) or, in some species, a fibrous network of a protein called spongin. This skeletal support gives shape and rigidity to the sponge as it functions as a filter feeder, drawing water through its porous body to capture micro–organisms. Because spicules are a distinctive, structural trait of sponges, they stand out as the characteristic feature among the options. The other possibilities describe features of different animal groups—segmented bodies, jointed limbs, and chitinous exoskeletons are associated with arthropods and related lineages—not with Porifera, which do not have tissues or organs and rely on their spicule- or spongin-based skeleton for support.