Sometime before 520 million years ago, animal life began to flourish as never before. The small shells, worms and even sponge-like enigmas of earlier eras suddenly unfolded into a new array of species ...

IMAGE: Caption: Carbonate layers hold carbon isotope evidence of the late Precambrian greening of the Earth. These are located in the Old Dad Mountains in California. Credit: L.P. Knauth, Arizona ...

Animal life is extraordinarily diverse and complex, having colonised almost all environments on Earth – from hostile hydrothermal vents in the deep sea to the skies across our continents. But all this ...

Goblet-shaped sea jelly relatives with miniature “arms.” A plump, legless creature resembling a sausage. Long, wormlike animals tipped with flat “holdfast” discs for anchoring to the seafloor.

Since soon after our planet formed, Earth's 4.6 billion-year-long history was dominated by single-celled life. Something dramatic happened about 500 million years ago called the Cambrian "explosion," ...

More than 500 million years ago, during what is known as the Cambrian period, the seas and oceans on Earth were filled with a myriad of marine animals, many of which have now become extinct. This ...

This animation created for Evolution: "Great Transformations" depicts creatures whose fossils were found at the Burgess Shale. As alien as these creatures seem, they are also surprisingly familiar.