What type of embryonic development do echinoderms demonstrate?

• A. Protostome
• B. Deuterostome
• C. Lophotrochozoan
• D. Ecdysozoan

Answer: (B)

Echinoderms show deuterostome development. In this pattern, the blastopore becomes the anus and the mouth forms later, and the early cell divisions are radial and indeterminate. The coelom forms by enterocoely, with pouches pinching off from the gut to create the body cavities. Although echinoderms mature with radial, pentaradial symmetry, their embryology aligns with deuterostomes, the same group that includes chordates. This distinguishes them from protostomes, where the mouth typically forms first from the blastopore, cleavage is often determinate and sometimes spiral, and coelom formation follows a different pattern.