BIOL 304 Lecture Notes - Lecture 12: Achieved Status, Pax6, Xiphophorus
5 Mar 2018
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Definitions of macroevolution: 90 papers: evolution/changes above the species level, large scale evolutionary patterns and processes, evolution on a long timescale, macroevolution is trying to explain a lot everything above micro evolution. Intermediate stages that could connect micro and macro-evolution. What should a good biological theory aspire to: explain 85% of the variation in the phenomenon. Homology: character/trait is present in most recent common ancestor. Homology of genes but not of morphology: for example, bat wings and bird wings same genes underlie the structures but are not the same. Homology of morphology but not of genes: similar bodyplans but different genes responsible for them. Parallelism: independently evolved morphologies, but being done with the same genes and developmental patterns. Essentials for an operational theory of mesoevolution: pattern: parallelism, mechanisms, conserved developmental modules facilitating bias, constraint, or a genetic path of least resistance, developmental plasticity.
