happy (198 th ) birthday chucky d.!!!

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

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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. - PowerPoint PPT Presentation

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

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

Page 2: Happy (198 th ) birthday Chucky D.!!!

Mutations are random• Luria & Delbrück experiment (1943)

Page 3: Happy (198 th ) birthday Chucky D.!!!

Mutations are random• Joshua & Esther Lederberg (1952)

Replica plating

Page 4: Happy (198 th ) birthday Chucky D.!!!

Phenotypic effect of mutations• Ranges from neutral to substantial

Antennapedia

Page 5: Happy (198 th ) birthday Chucky D.!!!

Distribution of mutational effects upon fitness

• Theoretical prediction, only now some data…

prop

ortio

n

deleterious beneficiallethal neutral

Page 6: Happy (198 th ) birthday Chucky D.!!!

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)

Page 7: Happy (198 th ) birthday Chucky D.!!!

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)

Page 8: Happy (198 th ) birthday Chucky D.!!!

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

Page 9: Happy (198 th ) birthday Chucky D.!!!

What adaptation is not…

Necessary

Perfect

Progress

Harmonious

Moral

Page 10: Happy (198 th ) birthday Chucky D.!!!

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*