How and why the Cambrian explosion occurred has been the subject of debate ever since fossils of this remarkable event were ...

The initial phases of animal evolution proceeded faster than hitherto supposed: New analyses suggest that the first animal phyla emerged in rapid succession -- prior to the global Ice Age that set in ...

Which group of animals evolved first? This problem has become a bone of contention among biologists. An international research team is now confident that the definitive answer is at hand: Sponges ...

At present there are many animal phyla that contain only a few species. The existence of these small phyla can be used to test assumptions about speciation and extinction in multicellular animals. We ...

A new study by University of Arizona biologists helps explain why different groups of animals differ dramatically in their number of species, and how this is related to differences in their body forms ...

Whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. So wrote ...

All placozoans are superficially identical. But comparative genomic data reveals the presence of different genera. This is the first time that a new animal genus has been defined solely by genomics.

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 -- ...