1. BIOS E-127 – 08.09.22 Prior theme music: http://www.overman.info/evolutionrocks.htmlhttp://www.overman.info/evolutionrocks.html “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)

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

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

4. 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)

5. How study adaptations? A. B. vs.

6. How study adaptations?

7. Linnaean classification Two major characteristics KingdomAnimalia PhylumChordata ClassMammalia OrderPrimates FamilyHominidae Genus Homo Speciessapiens

8. Tree of Life: primary divisions

10. Tree of Life: three “domains” Based on 16S rRNA (Woese, 1987):

11. Tree of Life: three “domains” Based on 16S rRNA (Pace, 1997):

12. Tree basics: meaning

13. Tree basics: rotation

14. Tree basics: shape

15. Tree basics: lengths, unrooted cladograms vs. phylograms

16. Tree basics: character change

17. Key phylogenetic terms

19. Monday (9/29): Phylogeny and horizontal gene transfer p.s.- No office hours from 4-5 pm this week.

20. Upcoming talks in microbial evolution… Tuesday, 9/23 Uri Alon (Weizmann Institute of Science) “Design principles of bacterial gene circuits" HMS Microbiology and Molecular Genetics Seminar Series Warren Alpert, Room 341 (Longwood) 12:30 pm Wednesday, 9/24 Marx & Girguis labs open house 6:30 – 8 pm, 3081 Biolabs All are welcome to come enjoy a beer and snacks and learn about work in our labs…