Happy (198 th ) birthday Chucky D.!!! Mutations are random Luria & Delbrck experiment (1943) Mutations are random Joshua & Esther Lederberg (1952) Replica plating Phenotypic effect of mutations Ranges from neutral to substantial Antennapedia Distribution of mutational effects upon fitness Theoretical prediction, only now some data proportion deleteriousbeneficial lethalneutral Natural selection Definition: Any consistent difference in fitness among phenotypically different biological entities (Futuyma, p.349) Requirement: variation in traits that effect fitness Selection always equal to evolution? Contrasts with drift chance rise of genotypes More than just success of individuals Cause & effect (Gould & Lewontin, 1979) Levels of selection Group selection Wynne-Edwards: self-regulation and restraint of individuals (ensure survival of the species) Related to balance of nature in ecology Williams: Only individual level benefits Species selection Genic selection Dawkins: The Selfish Gene (1989) What is adaptation? Noun vs. verb (vs. acclimation) Noun: [A] feature is an adaptation for some function if it has become prevalent or is maintained in a population because of natural selection for that function (Futuyma, p.355) the good fit of organisms to their environment (Gould & Lewontin, 1979) Preadaptation Exaptation Traits can be non-adaptive What adaptation is not Necessary Perfect Progress Harmonious Moral Looking forward Assignment: Revised plan from each group (1-2 pages) Microbiology review sessions: 2/15, 6 pm Brock 1, 2, 5 (General micro & metabolism) 2/20, 6 pm Brock 6, 9, 12, 13 (Microbial growth, basic virology, overview of bacterial & archaeal diversity) Special guest lecture: 2/22, 6 pm Daniel Segr, Origin of biological networks *pizza & beer will be provided*