The figure below shows the vertebrates and arthropods as being distantly related, yet each has features, like limbs and jaws, seen in no other groups. How can such obvious similarities be disregarded in favor of embryological development as a basis for classification?

Question

Quizplus · Accepted Answer

Embryos provide evidence of shared inherited features because they are securely protected during development and experience little selection pressure. This is why similarities in limbs and jaws seen in distantly related groups can be explained by a common ancestor. The fact that some groups have lost certain features, like limbs, is a secondary adaptation that does not contradict the evidence provided by embryo development.

The Figure Below Shows the Vertebrates and Arthropods as Being