bio notes

bio notes - Mutation introduces new alleles. Natural...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
5/3/07 CPS? : In a class of 100 students there are 9 who are left-handed (rr). Assume that handedness is not subjected to any evolutionary mechanism and that mutation is negligible. What’s the frequency of right-handed homozygotes (RR) in the class? B) 0.49 Freq of rr = 9/100 = q^2 Square root (q^2) = q = .3 P = .7 Freq of RR = p^2 = .49 Hardy-Weinberg frequencies: P = .44 Q = 1 - p = .56 CPS? : Which of the following is probably the mechanism of natural selection acting on rock pocket mice? B) predation by hawks and owls Evolutionary mechanisms = processes that can change allele frequencies in a population Natural selection produces adaptation. Genetic drift causes random fluctuations in allele frequencies. change in allele frequencies; causes allele freq. to drift up/down Ex: Population bottleneck : sudden decrease in population size ex: cheetas Gene flow (= migration ) equalizes allele frequencies b/w populations.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Mutation introduces new alleles. Natural selection: Directional selection decreases diversity by favoring one extreme phenotype in the population. o Natural selection shifts average value of trait toward one extreme or the other Stabilizing selection decreases diversity by favoring the average phenotype over both extremes. o Stabilizing selection decreases a populations genetic variation over time, but doesnt change its average trait value. Disruptive selection increases diversity by favoring both extremes, and selecting against the average. o Can result in speciation (formation of new species) CPS? : Which of following is not evolutionary mechanism since it cannot change allele frequencies in a population? C) Inbreeding Inbreeding (mating b/w relatives) reduces the frequency of heterozygotes and increases frequency of homozygotes in each generation....
View Full Document

Page1 / 2

bio notes - Mutation introduces new alleles. Natural...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online