Lecture11_slides_19Sep11

Lecture11_slides_19Sep11 - Deciphering Earth History:...

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Deciphering Earth History: Geology and Chronology Study of natural selection in populations is about a mechanism of evolutionary change But what actually happened? Big view of history of life Today: context of earth history, dating Wed: fossils and their preservation Fri: patterns of change in fossil record How can we reconstruct what happened? 1. Phylogenies: show patterns of common ancestry as inferred from shared characters. 1. Fossils : direct evidence of past life; diversity; morphology, origins, extinctions 1. Phylogenies show branching sequence human chimp mouse hair mammaryglands bipedal Humans and chimps share a more recent common ancestor than either does with mouse. We can infer traits of ancestors. present past 2. Fossils provide direct evidence of past life and we can date them.
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Phylogenies and fossil history together are a powerful combination for reconstructing the history of life! vertebrates jawed vertebrates bony fshes tetrapods What are fossils? They are the remains or traces of once living organisms. Fossils are generally found in sedimentary rocks age of sediments gives time of preservation Today’s goal is to develop the geological and chronological context for learning about fossil history. How do we know Earth & its life have a history? (interpreting the sedimentary record) Geological dating: how do you know how old it is? James Ussher (1650) Annals of the Old Testament, deduced from the first origins of the world Pre-modern Natural Philosophy In 1650, Ussher published the finding that creation occurred on the night prior to October 23, 4004 B.C. - The world is only a few thousand years old. -The world has always been pretty much as we see it today. Nicolas Steno (Niels Stensen) (1638-1686) “tongue stones” in rocks View started to change with the dissection of a shark in 1666!
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Steno’s big ideas: If an object embedded in a rock looks like it was once alive, then maybe it
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This note was uploaded on 01/01/2012 for the course BIOEE 1780 taught by Professor Harrison during the Fall '10 term at Cornell.

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Lecture11_slides_19Sep11 - Deciphering Earth History:...

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