F13 lecture 1 v2

Previous slide migra6on of beetles into the popula6on

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Unformatted text preview: ause this •  muta6on •  gene6c drig •  migra6on •  natural (and sexual) selec6on –  red = closely related to ecology adapta6on •  defini6on of adapta6on –  phenotypic evolu6on that increases fitness in an environment Brood parasitism •  some examples? Common Cuckoo (Cuculus canorus) http://en.wikipedia.org/wiki/ File:Clown_fish_in_the_Andaman_Coral_Reef.jpg http://en.wikipedia.org/wiki/Cuckoo http://hensteethblog.blogspot.com/ 2012/07/cuckoos-evolution-ofparasitic-arms.html adapta6on •  of the 4 causal processes listed above –  only natural selec6on can cause adapta6on –  the other three can affect the rate of adapta6on but do not cause adapta6ons to evolve an example •  deer mice and beetles are part of each others’ bio6c environment & deer mice prey on beetles –  the presence of deer mice could cause beetles that are able to secrete more defense chemicals to have higher fitness than those that secrete lower levels of these chemicals •  provided that the chemicals deter preda6on by mice –  if there is at least a par6al gene6c basis to the differences in levels of secreted defense chemicals, then alleles causing higher levels of secre6ons will increase in frequency in the popula6on •  this is the core process of ecological adapta6on – but does not alone mean that adapta6on will occur what could work against the poten6al adap6ve scenario in the previous slide? •  migra6on of beetles into the popula6on from popula6ons with lower average levels of defense chemicals •  gene6c drig if popula6on size...
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