BIOL 2040 Lecture Notes - Lecture 24: Genetic Drift, Heritability, Silver Eye
19 Apr 2016
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Document Summary
Adaptive radiation: tend to see a period of rapid diversification. Once niches are filled, lineages stay relatively constant: radiation of lineages that survived permian extinction. Many fish radiated in the triassic: end pre-cambrian mass extinction. Ediacaran fauna gone extinct fossils not seen in fossil beds dating back to the beginning of the cambrian: features in current major lineages were not seen in. Ediacaran lineages (bilateral symmetry, third layer of tissue during development: most major lineages of animals appear in the cambrian, diploblastic and radially symmetry animals appeared pre- Cambrian phyla able to radiate into niches left behind by extinct ediacaran. Using divergence in dna in major lineages to infer how long ago the lineages diverged: fossil record appearance of bilateria in cambrian explosion. Stem lineages that would later diverge into current lineages appear 900. Long before the cambrian explosion extinction of ediacaran allowed radiation of stem lineages in the cambrian.
