BISC 102 Lecture 6: Lecture 6
3 Mar 2017
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Document Summary
Earth (4. 6 billion years old) ~ 3. 5bya mostly water, hydrothermal activity, volcanic activity, intense uv light, thin atmosphere (composed of mostly n2; some: co2, meth, h2o; no o2), lots of lightning, lots of meteorites, life! (stromatolites) Evolutionary novelty = any newly acquired structure or property that permits the performance of a new function which in turn will open a new adaptive zone. Includes: partial/complete remains (ex/ bones) or traces (ex/ footprints) Preservation is biased: hard, aquatic, abundant, long-lived, lived in many different areas, recent-lived species are more likely to be captured. Stromatolites (evidence of life) = accumulation of sediments on photosynthetic cyanobacteria. Round rock form; common in fossil record. Banded iron (indirect evidence of life) = alternating layers of grey (iron oxides) and red (silica and hematite) = evidence of oxygen. Prokaryotes (bacteria, archaea): evolved first, metabolically complex but looks simple, no nucleus, has circular dna.
