Chapter 19

Question 1

4 driving forces of evolution

Answer 1

1. natural selection
2. Genetic Drift: The randomness of meiosis causes allele freq. to change
3. Gene flow: individuals from a population migrate to another population
4. Mutation

Question 2

Gene pool concept

Answer 2

All alleles from a given group combine randomly in a reproductive event

Question 3

Hardy weinburg assumptions

Answer 3

1. Random Mating
2. Inf. Population
3. No genetic Dirft
4. No gene flow
5. No mutation

Question 4

HLA (human leukocyte antigen) genes and dirty T-Shirt theorum

Answer 4

Genes that code for antigens for the immune system and present an heterozygotic advantage. To test how humans slect for these genes, researchers think that phermones are correlated to types of HLA genes and women perfer smells of opposite antigens

Question 5

Why interbreeding bad?

Answer 5

1. Its moraaly wrong in humans
2. The concept of interbredding depression (loss of fitness due to interbreeding) makes it bad

Question 6

Other non-random mating exmapels

Answer 6

sexual selection causes: Directional, stabilizing, and disruptive selection to occur

Question 7

The asymmetry of sex

Answer 7

Males and Females detremined fitness is based off of different criteria and result in females putting more energy in their offspring than males do.

Male fitness is capped by: #females he can mate w/
Female fitness is capped by: ability to gain resoruces

Question 8

Sexual Dimorphisms

Answer 8

Males and Females look different because females select for males that can demonstrate they have the best fitness and females need to survive more to raise offspring/ gather resources

Question 9

Founders effect vs. Bottleneck affect

Answer 9

The main similarity between is both causes allele frequencies to differ because of genetic drift, but the mechaicisms of how it happens is different:
Founder- Migration event
Bottleneck- extinction event

Question 10

How can gene flow affect fitness

Answer 10

1. Can introduce lost alleles in a population due to genetic drift
2. Movement off alleles between populations often reduced genetic differences

Question 11

How does mutations affect fitness

Answer 11

Good- Can RARELY introduce beneficial genes
Neutral- Commonly have no affect on the organism’s fitness
Bad- Can SOMETIMES cause system of an organisms to collapse and lower fitness

OVERALL: mutation is the ultimate source of gentic variation because it happens randomly and introduces new alleles