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Happy (198 th ) birthday Chucky D.!!!

Happy (198 th ) birthday Chucky D.!!!. Mutations are random. Luria & Delbr ü ck experiment (1943). Mutations are random. Joshua & Esther Lederberg (1952). Replica plating. Phenotypic effect of mutations. Ranges from neutral to substantial. Antennapedia.

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Happy (198 th ) birthday Chucky D.!!!

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  1. Happy (198th) birthday Chucky D.!!!

  2. Mutations are random • Luria & Delbrück experiment (1943)

  3. Mutations are random • Joshua & Esther Lederberg (1952) Replica plating

  4. Phenotypic effect of mutations • Ranges from neutral to substantial Antennapedia

  5. Distribution of mutational effects upon fitness • Theoretical prediction, only now some data… proportion deleterious beneficial lethal neutral

  6. 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)

  7. 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)

  8. 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

  9. What adaptation is not… Necessary Perfect Progress Harmonious Moral

  10. 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 Segrè, “Origin of biological networks” *pizza & beer will be provided*

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