Theme 4C (Part 2, Consequences of Change)

Question 1

Population Divergence

Answer 1

• Driven by nat sel or drift b/w environments
  *

• Pop who over time changes distribution to homozygous on opposite ends
• Over long period of time, allele fixation occurs and populations diverge as they are now distinct from one another

Question 2

Factors causing genetic divergence b/w isolated pops

Answer 2

• Genetic drift
• Founder effect & pop bottleneck
• Mutation
• Differenetial selection

Question 3

Speciation process

Answer 3

• Production of fixed genetic difs b/w pops
• Parent pop looks the same, similar phenotypes
• Pop splits physically, each on own evo trajectory
• New traits arise, beneficial common
• Nuetral fixation can occur in some traits

Question 4

Types of mutation

3

Answer 4

• Deleterious - Decreases fitness
  Nuetral - No affect
  Beneficial - Benefits

Question 5

Reproductive Isolation

Answer 5

• Can’t reproduce with one another, dif species
• 2 ways - Prezygotic + Postzygotic mechanism

Question 6

Prezygotic Mechanism

Answer 6

• Preventing mating from happening
• Prevent fertilization from happening

Question 7

Prezygotic Barriers

Answer 7

• Habitat isolation
• Behavioural Isolation
• Temporal isolation - Breed at dif times
• Mechanical isolation - Genitalia dif, pollinator isolation (flowers)
• Gametic isolation - Zygores don’t form

1 example: Great Dane female dog not able to mate with male chihuahua

Question 8

Postzygotic Mechanisms

Answer 8

• Prevent zygote development or reproduction

Question 9

Postzygotic Barriers

Answer 9

• Reduced hybrid viability - lower survival
• Reduced hybrid fertility - Hybrids sterile
• Hybrid breakdown - Hybrids can mate, but offspring have reduced fitness

Sorted from most common to least

Question 10

Outcomes of Renewed/Continued contact b/w pops

Answer 10

• Can hybridize readily
• Do not hybridize at all
• Hybridize but offsprings have reduced fitness

Question 11

Modes of Speciation