Get 1 week of unlimited access
Class Notes (1,053,415)
US (414,813)
IUP (150)
ANTH (11)

ANTH222 Lecture Notes - Daphne Major, Phenotype

1 pages98 viewsFall 2012

Course Code
Dr.Francis Allard

This preview shows half of the first page. to view the full 1 pages of the document.
Notes: 9/7 Evolution/Natural Selection “In Action”
Phenotype (form evolutionary perspective)
Ex. skin color, finches beaks
Peter and Rosemary Grant- Galapagos experiment on natural selection “in action” on Medium
Ground Finches on Daphne Major (an island) 1976-78
1. During drought, finches with “small” beaks didn’t reproduce as much because they were
unable to break the larger/harder seeds (population dropped from 1200 to 180)
2. Before drought, larger variation in beak depth, after increasingly “bigger” to eat
larger/harder seeds
3. Offspring tended to have beak depth of parents
(*Fits all Postulates of Darwin’s Theory)
Directional Selection- normal distribution of traits shifts right or left on graph
Stabilizing Selection- pressure at either side of variation, no evolution happening but natural
selection still continues (species cannot be static)
Figure 1.9 on Worksheet (H1)
1. Height of bar goes down, aka less birds (population drop)
2. Average beak depth shifts to the right, aka average beak depth is larger than before
3. Curve shape of bars didn’t change, variation still exsists
You're Reading a Preview

Unlock to view full version

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.