Question

Some animals generate two germ layers during gastrulation. They are called diploblasts. Other animals generate three germ layers as a result of gastrulation. They are called triploblasts. Triploblasts can be further categorized as either protostomes or deuterostomes. Can you identify the fate of the blastopore in each category of animal?

Answer 1

Diploblastic blastopore - gastrovascular cavity

Protostome blastopore - mouth

Deuterostome blastopore - anus

Explanation:

Blastopores are structural indentations formed on the embryo during the gastrulation stage and this develops into mouth or anus depending upon the type of the embryo.

Diplolbastic (cnidarians) blastopores develop into the gastrovascular cavity in organisms like hydra

Triploblasts with three embryonic germ layers includes acoelomates, eucoelomates, and pseudocoelomates and the blastopores transform accordingly.

The blastopores of the triploblastic eucoelomates like the protosomes (mollusks, arthropods, annelids) transforms to the mouth, denoting ‘mouth first’; while that of the deuterostomes (chordates) transform to anus, denoting ‘mouth second’.