AP BIOLOGY

Detailed explanation-1: -The blastula develops a pore at one end, called a blastopore. If that blastopore becomes the mouth of the animal, the animal is a protostome, and if it forms an anus, the animal is a deuterostome.

Detailed explanation-2: -The mouth of the Protostomia (proto, “first”; stoma, “mouth”) develops from the first opening into the embryonic gut (blastopore). The coelom (body cavity) forms from a split in the embryonic mesoderm (middle tissue).

Detailed explanation-3: -The endoderm (of the gastrula) surrounds a cavity, called as the archenteron, which has an opening to the exterior at the point at which invagination occurs and this opening is called blastopore.

Detailed explanation-4: -The key difference between protostomes and deuterostomes is the fate of the blastopore during their embryonic development. The blastopore in a protostome develops into a mouth, whereas the blastopore in deuterostomes develops into an anal opening.