W12 special topics

Question 1

What is an invasive species?

Answer 1

rapid spread and dominance of an introduced species

Question 2

What is an introduced species?

Answer 2

human-assisted dispersal of a species beyond its historic range

Question 3

Genetic variation of an introduced species

Answer 3

Prediction: genetic variation will be reduced in the introduced range vs. the native range
1. Colonising populations often experience high levels of drift
- Demographic bottlenecks
2. Genetic bottlenecks can have fitness costs
1E.g. decline in hatching success vs. source population

Question 4

the invasion paradox

Answer 4

Many introduced species somehow thrive in new environments when they should be suffering from a loss of genetic diversity (limited adaptation) and inbreeding depression (increase in deleterious alleles)

Question 5

What is a plant mating system?

Answer 5

the mode of transmission of genes from one generation to the next through sexual reproduction- Includes selfing and outcrossing

Question 6

factors that impact the evolution of selfing from outcrossing

Answer 6

• Change in floral morphology correlated with selfing: Smaller flowers, less attractive, fewer rewards, lower pollen production, smaller stigma-anther distance
• Change is life history with evolution of selfing: Annuals (live for only one year) tend to be selfer- Due to reproductive assurance Perennials (live for many years) tend to be outcrossers
  Due the costs to future survival and reproduction of reproductive assurance

Question 7

Genetic consequences of sefling

Answer 7

1. Reduced effective recombination
2. Selective sweeps, and hitchhiking, will greatly reduce neutral diversity
3. Fixation of deleterious alleles
4. Selection and drift reduce genetic variation in inbreeding populations