1. “Evolutionary speculation constitutes a kind of metascience, which has the same intellectual fascination for some biologists that metaphysical speculation possessed for some mediaeval scholastics. It can be considered a relatively harmless habit, like eating peanuts, unless it assumes the form of an obsession; then it becomes a vice” (Stanier, 1970) BIOL E-127 11.08.31

2. An example story (Nature 394:69-72)

3. Experimental design

4. Diversity observed in still medium in 7 days

5. Diversity & cell counts over time in each environment StillShaken

6. Maintenance of high diversity requires continued heterogeneity shaken still shaken still

7. Fitness of each is ‘frequency-dependent’

8. And a world was created in 7 days…

9. Evolution before Darwin Aristotle: Scala Naturae Linnaeus: Systema Naturae (1735) –“Undertaken in hope of discovering the pattern of God’s creation”

10. Evolution before Darwin Lamarck: Philosophie Zoologique (1809)

11. Darwin & Wallace Darwin spent 5 years on HMS Beagle (1831-1836) On September 28 th, 1838 (29 years old), made connection between Malthus and organisms 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)

12. Darwin and natural selection Two major tenets: –“[A]ll species, living and extinct have descended without interruption from one (or a few) original forms of life” (Futuyma, p.21) –“[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.” (Darwin, 1859)

13. After Darwin Big problem: Solution: Fisher, Haldane, Wright, Mayr, Huxley, Stebbins, Simpson, Dobzhansky…

14. Are mutations random & independent of selection? Luria & Delbrück experiment (1943)

15. Joshua & Esther Lederberg (1952) Are mutations random & independent of selection?

16. For Wednesday (9/7) (pages 222-232, 253-264)

17. MSI Chalktalk Breakfast Friday, Sept 2 8:45-9:30 am “Multidrug Resistant Enterococci: What makes a good bug go bad?” Michael Gilmore HMS-Ophthalmology Please join us for coffee/tea/pastries at 8:30 am - Directions to 24 Oxford St: http://www.msi.harvard.edu/ov_dir.htmlhttp://www.msi.harvard.edu/ov_dir.html -Join MSI-news listserv: Email: listserv@listserv.med.harvard.edu and in the body of your email, copy the text: subscribe msi-newslistserv@listserv.med.harvard.edu