What Is the Primary Distinction Between Protostomes & Deuterostomes?

Distinction

• The opening of the digestive tract in an embryo is called the blastopore. The primary difference between protostome and deuterostomes concerns whether the blastopore becomes a mouth or an anus. Protostome means "mouth first," reflecting the fact that in this type of animal, the embryo first forms a mouth from the blastopore and then later forms an anus. In deuterostomes, meaning "mouth second," the anus forms from the blastopore and the mouth follows later.

Cleavage

• Deuterostomes have indeterminate cleavage, every early cell is the same. A cell taken from a four-cell embryo could form a whole new embryo by cell division. Protostomes have determinate cleavage, cells differentiate and if isolated, are capable of forming a normal new embryo.

Examples

• Echinoderms and chordates, which include mammals, are a few examples of deuterostomes. arthropods, annelids and mollusks are examples of protostomes.