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PHYS 0106 (Spring, 2001) Earth History Timeline |
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| Phanerozoic Eon: Paleozoic Era: Cambrian Period | |||
Timeline Links Phanerozoic Neoproterozoic Mesoproterozoic Paleoproterozoic Archean Other Links Historical Geology Page Physical Geology Page Mike's Home Page |
Writer/Researcher: Monica Ribeiro Editor: Michelle Melikian Web Page Builder: Monica Ribeiro The Cambrian Period of the Paleozoic, about 500 million years ago, ushered in an explosion of life and saw the development and evolution of many new species. The Tommotian Age, which takes its name from a rock series in Siberia, produced fauna different than any other seen in the early Cambrian. A new category of life was spawned during this time and is now referred to as SSF - small, shelly fossils. SSF's were small in proportion, and consisted of organisms which are not easily aligned with modern fauna.
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The main feature which distinguishes the fauna of the Tommotian is the development of skeletal structures. Because of this, many of these new animals have been preserved in the fossil record. Although we can only speculate about the muscular structure of animals such as the trilobite, their skeletal form is easily recognizable even today because of the abundance of their fossilized skeletons. Another animal to come out of the Tommotian was the brachiopod. Although these two animals, and other creatures with far stranger and imposing structures, did not survive beyond the Paleozoic, the descendent of the mollusk saw the birth of its predecessors during the Tommotian. Some typical shapes for Tommotian fauna included cones and tubes.
