Unit 3-Lesson 5

Question 1

Define Allele frequency

Answer 1

Allele frequency: a numeric number of how common you see a particular trait in a population (usually in percentage)

Question 2

Define Microevolution

Answer 2

Microevolution: small changes that occur over time that may lead to a change in allele frequency

Question 3

What are the factors affect allele frequency?

Answer 3

• Mutation
• Gene flow
• Non-random Mating
• Genetic Drift
• Natural Selection

Question 4

What is gene flow?

Answer 4

The movement of alleles from one population to another due to the migration of individuals

If the grey wolf finds another mate in the new population, it will introduce new gene into that gene pool. Thus increasing genetic diversity

Question 5

What is non-random mating?

Answer 5

• Non Random Mating: based on preferred phenotype (or due to inbreeding). This will lead to less variation of alleles within the population
  
  • Humans choose mates based on characteristics/values

Question 6

What is inbreeding?

Answer 6

Inbreeding: closely related individuals breed
E.g. Self fertilization in plants, purebred dogs

Question 7

What is random mating?

Answer 7

Random Mating: partners are randomly chosen. There is no likelihood that one organisms will be chosen over another. This enables to be greater variation of alleles in the population

Question 8

What is genetic drift?

Answer 8

Genetic Drift: isthe change in frequency of an existing gene variant in the population due to random chance

Question 9

What are two situations that can lead to to significant genetic drift in large populations?

Answer 9

Founder effect
Bottleneck effect

Question 10

Explain the founder effect

Answer 10

Founder Effect: the reduction in genomic variability that occurs when a small group of individuals becomes separated from a larger population

Question 11

Explain the bottleneck effect

Answer 11

Bottleneck Effect: a population is reduced in size due to natural disasters, habitat loss, or overhunting

Question 12

What is sex selection?

Answer 12

• Sex Selection: competition for mates between males and choices made by females
  
  • E.g. Visual display (peacocks)

Question 13

What is sexual dimorphism?

Answer 13

• Sexual dimorphism: difference in appearance between males and females
  
  • E.g. Green head in male mallard ducks and antlers on male deer

Question 14

What are the types of natural selection that affect frequencies of heritable?

Answer 14

• Stabilizing selection
• Directional selection
• Disruptive selection

Question 15

What is stabilizing selection?

Answer 15

Stabilizing Selection: favours intermediate phenotypes and acts against extreme variants of the phenotype

Question 16

What is directional selection?

Answer 16

Directional Selection: favours phenotypes at one extreme over the other

Question 17

What is disruptive selection?

Answer 17

extremes of a range of phenotypes rather than intermediate are favoured