Final Week: Lec 1 Flashcards
How do we calculate background extinction rates?
fossil record
What are 4 human-caused environmental changes that increase the extinction rate?
- habitat destruction
- invasive species/disease
- pollution and climate change
- overexploitation
What is a prominent role of conservation genetics?
monitor the effects of declining populations
What is a bias behind our knowledge of extinctions?
monitoring is taxonomically biased
What is a subspecies?
for the purpose of conservation, they have a different pattern of evolutionary adaptation
- sometimes other taxonomic justifications
What are evolutionary significant units?
populations of the same species that are reproductively isolated and may therefore have different adaptations
What are management units?
populations that are demographically independent from each other
What are the two kinds of conservation units?
- evolutionary significant units
- management units
What is an example of a conservation unit based on genetics?
Algonquin wolf
- one of the last Eastern wolf populations
- heavy introgression from coyotes and grey wolves (hybridization)
What is the value of hybrids in conservation?
subjective, differs by case
In conservation genetics, what types of variation are best for describing demographic processes such as gene flow and drift? Why?
neutral variation!
adaptive variation may be fixed in a population, and won’t reveal anything useful
What is the use of adaptive markers in conservation genetics?
can delineate gene functions, so outlier Loci can reveal specific adaptations between environments
- can delineate conservation units when neutral markers can’t
- be careful not to divide management units based on drift
Why are small populations at higher risk?
- higher genetic drift (low Ne)
- drift more likely to overpower selection
- small pops tend to be more isolated
- small populations tend to have higher inbreeding
How might we determine the baseline level of genetic diversity?
compare genetic diversity over time or between populations
- can perform genomic coalescence to infer past Ne
What does low genetic diversity mean for a population’s conservation?
- less likely to adapt to changing environmental conditions
- lower genetic diversity means fewer traits to respond to selection pressures
What did the shrimp experiment show about genetic diversity and conservation?
higher genetic variation leads to better adaptation to environmental change
- more diverse pops survived salt stress
When is adaptive evolution stronger?
when Ne is larger
- more genetic lineages improves chance of adaptive mutations
- high Ne means selection overpowers drift
- s > 1/(4Ne)
In conservation, what can genetic drift interfere with?
adaptive potential
How does a large Ne affect the balance between selection and drift?
with a large enough Ne, even weak selection is stronger than drift
