sept 1 - 2 Tuesday, September 01, 2009 9:30 AM How...

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Insects are diverse, but have small fossil record Mollusks, chordates, protozoa, has comparable fossil record compared to ones alive today, more fossils than living ones, fair amount of diversity How extensive is the fossil record? Body fossil: skeleton or hard parts Trace fossil: trace of the organisms activity Micro fossil: skeletons of tiny or unicellular organisms Extraordinary fossil: soft part preservation in fossil organisms What are the different types of fossils? More than 50% of the fossil record is preserved in the Cretaceous sequence on upwards 99% of the fossil in 12% of the geologic time is held in the Phanerozoic v. ~1% of the fossil in 88% of the geologic time is held in the Pre-Cambrian (Phanerozoic bias) Precambrian contains mostly igneous, met rocks, or badly deformed sedimentary rock; therefore, does not hold fossils well Phanerozoic has mostly sedimentary rocks, slightly deformed, or undeformed Fewer fossils in Phanerozoic, simple fossils, microfossils -> preserved in cherts Named and described fossils <1% of what has lived in the past Bias in the amount of paleontological systematics done: need to find and collect fossils in the field, prepare, reconstruct, describe and illustrate them back in the lab Conclusion: The fossil record has a bias in terms of preservation… although fossils are found in the Precambrian record, the bigger bulk of the fossil record is preserved in the Phanerozoic sequence. Furthermore, sedimentary rocks preserve the fossil record better than igneous rocks.
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This note was uploaded on 02/21/2010 for the course GEO 420k taught by Professor Staff during the Spring '08 term at University of Texas.

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sept 1 - 2 Tuesday, September 01, 2009 9:30 AM How...

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