BIOS E-127 10.09.13

“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)

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. p.592)

Points re: “Spandrels”• Spandrels (p.581)

• Dr. Pangloss (p.583)

• First target? (p.583)

• Natural selection can’t drive extinction (p.584)

• Only brake upon perfection? (p.585)

• Tyrannosaurus? (p.587)

• Bluebirds? (p.588)

• G&L other possibilities? (p.590)

• “Baupläne”? (p.593)

• In ecology too…

How study adaptations?

A. B.

vs.

How study adaptations?

Microbial systematics

• Formerly Pseudomonas (partial list): Ralstonia, Burkholderia, Hydrogenophaga, Sphingomonas, Methylobacterium, Cellvibrio, Xanthomonas, Acidovorax, Hydrogenophillus, Brevundimonas, Pandoraea

multi-C C1(& all use methanol)

16S rRNA as phylogenetic marker• Why a good molecule?

70S 30S 50S

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

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

Bacteria & Archaeal: all genomes as of 12 Feb., 2010

(Lee, Robinson & Marx, in prep)

Tree basics: meaning

Tree basics: rotation

Tree basics: shape

Tree basics: character change

Monday (9/20): Phylogeny & horizontal gene transfer

& comment…