Evolution before Darwin• Lamarck: Philosophie Zoologique (1809)

OEB 192 – 10.09.08Prior theme music: http://www.overman.info/evolutionrocks.html

Darwin & Wallace

• In June 1858 received manuscript from Wallace “On the Tendency of Varieties to Depart Indefinitely form the Original Type”• Rushed to present his work at the same time, then wrote

a 490 page abstract… (1859)

Darwin and natural selection

• Two major tenets (Darwin, 1859):

– “[A]ll species, living and extinct have descended without interruption from one (or a few) original forms of life”

Darwin and natural selection

• Two major tenets (Darwin, 1859):

– “[A]ll species, living and extinct have descended without interruption from one (or a few) original forms of life”

– “[I]f variations useful to any organic being ever occur, assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance, these will tend to produce offspring similarly characterised. This principle of preservation, or the survival of the fittest, I have called natural selection.”

After Darwin• Big problem:

• Solution:

• Fisher, Haldane, Wright, Mayr, Huxley, Stebbins, Simpson, Dobzhansky…

Are mutations random & independent of selection?

• Luria & Delbrück experiment (1943)

• Joshua & Esther Lederberg (1952)

“Replica plating”

Are mutations random & independent of selection?

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)

How study adaptations?

A. B.

vs.

How study adaptations?

Monday (9/13): Phylogeny and the tree of life

Tanja BosakMIT

“Life between the Snowballs”

Thursday, September 9th @ 6PM

Location: Center for the Environment (Rm 310)24 Oxford St, Harvard University, Cambridge

Please join us for a wine and cheese reception at 5:30 pmHost: Ann Pearson- MSI Seminar Schedule: http://www.msi.harvard.edu/thursdays.html- Directions to 24 Oxford St:  http://www.msi.harvard.edu/ov_dir.html