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This 1 page Class Notes was uploaded by Mary-elizabeth Notetaker on Sunday August 28, 2016. The Class Notes belongs to Bio 409 at University of Louisville taught by Jeffery Bara in Fall 2016. Since its upload, it has received 17 views. For similar materials see Evolutionary Biology in Biology at University of Louisville.
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Date Created: 08/28/16
Ch 2 • Views on history of life: Special creation Darwinian theory of descent w modiﬁcation ‣ Microevolution- change through time • Vestigial stxs/genes ‣ Speciation • Species- interbreeding groups/pops ‣ Macro evolution-fossils • Transitional forms- same species w diff forms..Have traits typical of distinct organism groups even tho same species ‣ Common ancestry • Homology- get nested patterns of traits to predict when species/traits arose • Molecular homology- shared ﬂaws provide further evidence Pseudogenes- broken genes and accumulate ﬂaws ‣ Comparing to mother gene shows how old it is ‣ Life on earth is old CH 3 • relationship btwn pattern and process • Nat selection- process in which events act on individuals but affect pops only process that leads to adaptation Explains species divergence and life diversity Darwin's dangerous idea- explains apparent design of the living world w/out recourse to supernatural Darwin's postulates- claims about nature of pops of orgs..must have all 4 • tested w direct evidence • Identify logical consequence • Can test whether logical consequence is observed ‣ Phenotype variation (mutation) ‣ Heritable variation ‣ Differential survival ‣ Differential success is attributable to certain alleles/allele combos Darwinian ﬁtness- relative measure of indivs ability to survive and reproduce • indivs do not change • Pop changes as result of cold arithmetic ‣ ﬁtness of biological entity- avg over capitals rate of inc in numbers • components relate to prob of survival to reproductive age • Avg number offspring produced from females(eggs/seeds) or males(sexual selection) • Prob and avg so ﬁtness is deﬁned for indivs w particular genotype Nature of Nat selection ‣ acts on standing variation to inc ﬁtness in current environment,may not help in diff place or in future ‣ Acts on existing traits but new ones can emerge • exaptation- trait that is used in novel way • Directional selection- rare/extreme phenotype favored,causing allele freq to shift over time in direction of that phenotype selects for one extreme,moves pop in one direction • Disruptive selection- individuals w extreme/rare values of traits have highest ﬁtness increases variation Moves towards both extremes,most common is selected against • Stabilizing selection- purifying selection...Decrease in variation around mean w/out changing mean • Frequency dependent selection- ﬁtness of genotype dependent upon freq ex) mimics ‣ when small amt of mimics has high ﬁtness BC higher prob predators ate real thing and will avoid mimics
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