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 PresentationTRANSCRIPT
Happy (198th) birthday Chucky D.!!!
Mutations are random• Luria & Delbrück 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…
prop
ortio
n
deleterious beneficiallethal neutral
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 Segrè, “Origin of biological networks”
*pizza & beer will be provided*