BIOLOGY 1M03 Lecture Notes - Lecture 14: Even-Toed Ungulate, Permineralization, Proterozoic
8 Oct 2015
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Biology 1m03 - lecture 14 - phylogenies and the history of life (continued) More-recently obtained and analyzed data on gene sequences called short interspersed nuclear elements (sines) show that whales and hippos share several sine genes that are absent in other artiodactyl groups. These sines are shared derived traits (synapomorphies) and support the hypothesis that whales and hippos are closely related. A fossil is the physical trace left by an organism that lived in the past. The fossil record is the collective fossil specimen set that has been found throughout the world. The fossil record provides the only direct evidence about what organisms that lived in the past looked like, where they lived, and when they existed. Most fossils form when an organism is buried in sediment before decomposition occurs. The four fossil types are recognized: intact, compression, cast, and permineralized. For example, a tree lives in a swampy (low oxygen) habitat.
