BIOL 2400 Lecture Notes - Lecture 2: Teleost, Amniote, Dinosaur
12 Sep 2017
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Document Summary
Paleontology: nature of fossil record mostly hard parts, dating the fossil record with radioactive decay. Early multicellular eukaryotic life took three billion years to appear. Large complex animals (lagerst tten soft parts: ediacaran fauna 575 mya (precambrian period, chenjiang fauna 515 mya (cambrian period, burgess shale fauna 505 mya (cambrian period) Sedimentary rocks form layers from the deposition of small particles in basins along continental shelves and contain fossils. Fossils: perimineralized, casts and molds, exceptional; preservation (includes soft parts but rare) Gradual vs. punctuated evolution: h1: jumps (or punctuated because of large change in morphology in next strata above homeotic mutations, h2: jump not really punctuated evolution but artifact of preservation especially in older strata. Radiometric dating estimates the age of the earth at 4. 6 billion years old. Earliest bacteria fossils: potentially 3. 45 bya, abundant by ~2. 6 bya, stromatolites corresponding to rise in oxygen.
