Evolution/HW

Question 1

Population

Answer 1

Group of sexually reproducing organisms that can interbreed (single species)

Question 2

Phenotype Frequency

Answer 2

• # w/ one phenotype/total population
• # w/ other phenotype/total pop
• =1

Question 3

Allele Frequency

Answer 3

• Frequency of A
  
  • Frequency of AA + 1/2 freq of Aa
• Frequency of a
  
  • Frequency of aa + 1/2 freq of Aa

Question 4

Requirement for HW equilibrium

Answer 4

• Infinite population size (no genetic drift)
• no mutation
• no migration (no gene flow)
• no differential survival and reproduction (no natural selection)
• random mating (equal probability of mating w/ everyone in the population)

Question 5

Genetic Drift

Answer 5

Chance events

Question 6

Sampling error

Answer 6

• Genetic drift in small populations
• Frequencies may rise and fall due to random chance in small pop

Question 7

Bottleneck Effect

Answer 7

Surviving members of a catastrophic event can have different allele frequencies than source population, and new pop. experiences evolution in effect.

Question 8

Founder effect

Answer 8

Founding members of a new pop. have different allele frequencies than the original source pop. and new pop. experiences evolution in effect.

Question 9

Migration in HW

Answer 9

Changes allele frequencies in both populations

Question 10

Why is HW useful?

Answer 10

We can examine what may be causing allele frequencies in a population to change between generations

Question 11

Natural selection

Answer 11

• Differential survival and reproduction
  
  • some individuals will survive better and reproduce more than other individuals

Question 12

4 requirements for natural selection

Answer 12

1. More offspring produced than can survive
2. Phenotypic variation
3. Fitness differences associated with variation
4. Heritablitiy

Question 13

Relative fitness

Answer 13

contribution individual makes to the gene pool of the next generation relative to the contribution of other individuals

Question 14

Why can’t natural selection make perfect orgs?

Answer 14

• Selection can only act on existing variation
• Evolution is limited by historical constraints
• Adaptations are compromises
  
  • same structure performs many functions
• Environment changes unpredictably

Question 15

Modes of selection

Answer 15

• Directional selection
• Stabilizing selection
• Disruptive selection
• Balancing selection

Question 16

Directional selection

Answer 16

changes the average value of a trait

Question 17

stabilizing selection

Answer 17

reduces the amount of variation in a trait

Question 18

Disruptive selection

Answer 18

increases the amount of variation in a trait

Question 19

Balancing selection

Answer 19

• Environment varies but variation maintained
• Frequency dependent selection
  *

Question 20

Sexual selection

Answer 20

Differences in reproductive rates due to differences in their mating success

Question 21

secondary sexual characteristics

Answer 21

• characteristics of males and females not directly involved in process of reproduction
  
  • antlers, peacock tail, mating calls etc

Question 22

Parental investment

Answer 22

• time and energy spent constructing and caring for offspring
• larger for females than males

Question 23

Intrasexual selection in males

Answer 23

• combat
• sperm competition
• infanticide

Question 24

intersexual selection in females

Answer 24

• Female choice
  
  • evaluate male quality