This is a simplified evolutionary tree of six representative animal phyla, illustrating differences in body form, habitat, and species numbers among them. This visual may only be used in conjunction ...

The group with the world's simplest animals—tiny blob-like life forms with no organs and just a few cell types—finally has a fleshed-out family tree built by a research group led by the American ...

We know that some animals are bilaterian—meaning they display bilateral symmetry—while others are not, but nature is rarely so black-and-white.

Nearly 30 years ago, a research vessel off the southeast coast of Australia dragged up samples of the sea floor from depths of 400m and 1000m. Hidden away within the samples were a few unexpected gems ...

The Cambrian explosion was an extraordinary phenomenon in the evolution of life on the planet that led to the emergence of many animal phyla and the diversification of species. During this period, ...

General animal biology: Frog as a representative animal -- Materials of the animal body -- Body covering, skeleton, and body muscles -- Digestive systems and metabolism -- Circulatory systems -- ...