There are millions of different types of living things on Earth. In order to keep track of them all, scientists put living things into groups based on characteristics that they have that are the same.

Tidal marshes : home for the few and the highly selected / Russell Greenberg -- The Quaternary geography and biogeography of tidal saltmarshes / Karl P. Malamud-Roam [and others] -- Diversity and ...

A stunningly-preserved, half-billion year old fossil of a strange Cambrian creature could shift our understanding of how a sister group to vertebrates evolved, a new study suggests. The fossil, ...

Scientists have long puzzled over the gap in the fossil record that would explain the evolution of invertebrates to vertebrates. Vertebrates, including fishes, amphibians, reptiles, birds, mammals, ...