BIOC50H3 Lecture Notes - Lecture 18: Punctuated Equilibrium, Morning Glory, Macroevolution
22 Dec 2018
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Phylogenetic rates: trait evolution (e. g. body size) Taxonomic rates: species or higher level of taxa originate. Graph: data is clumped the increase is not gradual but just jumps in the rate of how the character is growing. Phyletic gradualism: gradual increase of rate. Punctuated equilibrium: different equilibria for body sizes, phylogenetic rates and taxonomic rates are closely linked together. Punctuated gradualism: speciation does not have to occur, rapid spurts from one equilibrium to another. Something abrupt happens which causes gradual but economic change. Genetic or developmental constraints (e. g. marsupial digits) Stabilizing selection: we have selection to maintain the character state that we currently have, effective environment they are more constant over time. Gene flow swamping: species with a large geographic range is likely to undergo local adaptation, major reason why we have lack of evolutionary change in a population, local adaptation can now be free for rapid speciation.
