Academic journal article The Science Teacher

Fossil Animals

Academic journal article The Science Teacher

Fossil Animals

Article excerpt

The fossil remains of some of the first animals with shells--ocean-dwelling creatures that measure a few centimeters in length and date to about 520 million years ago--provide a window on evolution at this time, according to scientists. Their research indicates that these animals were larger than previously thought.

John Moore, a PhD student in the Department of Earth Science at the University of California, Santa Barbara (UCSB), and his collaborators analyzed fossils from the Early Cambrian epoch. During this important time in Earth's history, there was a tremendous diversification of animal life in the oceans. Many of the major animal groups that are still alive today appeared at this time, and many unusual groups went extinct. In particular, the Cambrian epoch marked the first widespread occurrence of animals with shells or other hard parts. Many of these early animals had complex external armors containing dozens to thousands of tiny pieces. When the animals died, the armor fell apart. From the resulting jumbled puzzle pieces, Moore and his research team discerned what the animals were like, and how they are related to other animals.

"In our study, we focused on a strange Cambrian creature, called Cambrothyra," says Moore. He explained that Cambrothyra fossils look like tiny jars or vases--a few tenths of a millimeter long. …

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