Explain Protostomes vs. Deuterostomes breifly?
Branching Evolutionary Lines : It appears that the Coelomate animals separated into two divergent lines of evolution in terms of the way embryos develop. In the embryonic development sequence of one group (including the mollusks, annelids, and arthropods), the mouth is the first opening in the digestive tract to develop. That is, the mouth forms before the anus. Such animals are referred to as Protostomes. In the second group of Coelomates (the echinoderms and chordates), the anus forms prior to the development of the mouth; these animals are called Deuterostomes. A clear evolutionary relationship is reflected in the fact that all of the species within each group share the same pattern of embryonic development.