The Cambrian fossil record indicates that most animal phyla had diversified and inhabited the Earth's oceans approximately 518 million years ago. But even though chordates—the group that includes ...
Life began on earth more than 3.5 billion years ago, but the history of humans and other vertebrates accounts for only a fraction of this timescale. Chordates (a group that includes vertebrates) and ...
An Introduction to the Comparative Anatomy, Embryology and Evolution of Chordate Animals. By Dr. G. R. de Beer. (Text-Books of Animal Biology.) New edition. Pp. xv ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results