BIOC50H3 Lecture Notes - Lecture 18: Cyanidin, Punctuated Equilibrium, Phyletic Gradualism
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Rates of evolution: we can distinguish between: phylogentic rates: rates at which single characters ir complexes of character evolve, taxonomic rates: the rates at which species or higher taxa originate. Graph: time on y-axis and a character on x axis: (a) hypothetical (a) you could say :size increases linearly through time or size increases in abrupt changes. (b) phyletic: linear , traditional model. Evolution change is gradual and not associated with speciation (c) punctuated equilibria : idea that we have statis (consistent) and punctuated rate of evolution. Evolution happens in punctuated bursts. (d) punctuated gradualism:same as equilibria . gradualism however doesn"t result in separate species forming. Phylogentic rates and taxanomic rates not associated : no new species: phyletic gradualism, punctuated gradualism. Phylogentic rates and taxanomic rates are closely associated : punctuated equilibria. This pattern is referred to as punctuated equilibrium: long periods of little change (which are called stasis) interrupted by brief episodes of much more rapid change.
