He doesn't even have a head. If Blob had been born with a spine, or backbone, he would have been a vertebrate. If we give Blob some legs and a head then he can start to move about. There are lots ...

By contrast, adaptive immunity, which involves lymphocyte-like cells and the antigen-binding receptors they express, is restricted to vertebrates. A major departure in adaptive immunity is evident ...

A fossil analysis suggests that the yunnanozoan, a wormlike fish that flourished around 520 million years ago, sported structures that were the precursors of the head and jaws of modern vertebrates.