LIFESCI 7B Chapter Notes - Chapter N/A: Burgess Shale, Trace Fossil, Environmental History
15 Feb 2019
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Document Summary
Fossils provide direct documentation of ancient life, and so, in combination, fossils and phylogenies provide strong complementary insights into evolutionary history. First, fossils enable us to calibrate phylogenies in terms of time. It is one thing to infer that mammals diverged from the common ancestor of birds, crocodiles, turtles, and lizards and snakes before crocodiles and birds diverged from a common ancestor. The evolutionary relationship between birds and crocodiles highlights a second kind of information provided by fossils. Not only do fossils record past life, they also provide our only record of extinct species. 23. 7 contains a great deal of information, but it is silent about dinosaurs. Fossils demonstrate that dinosaurs once roamed earth, and details of skeletal structure place birds among the dinosaurs in the vertebrate tree. A third, and also unique, contribution of fossils is that they place evolutionary events in the context of.
