Population Genetics and Natural Selection

Question 1

Evolution

Answer 1

1. Gradual change at the population level
2. Change in frequencies of alleles/phenotypes in a population

Question 2

Peppered moth

Answer 2

Biston betularia

Question 3

Two major mechanisms of Evolution

Answer 3

Genetic Drift
Natural Selection

Question 4

Natural Selection vs Genetic Drift

Answer 4

Natural Selection
- traits chosen based on survival advantage
- Not random
- Requires evidence

Genetic Drift
- random selection
- traits are loss or fixated through completely random chance events
- default mechanism of evolution

Question 5

Natural Selection

Answer 5

Selection of traits based on fitness [the ability to survive and pass down traits/genes to offspring]

Question 6

Red Queen Hypothesis

Answer 6

The same traits will not always be ideal due to everchanging environmental conditions; evolutionary arms race

Question 7

Adaptation

Answer 7

Trait that increases fitness

Question 9

Ecospecies/Ecotype

Answer 9

geographically distinct VARIATION of a species responding to specific environmental conditions; they can still reproduce with one another

Question 10

4 hallmarks of Natural Selection accdg to Charles Darwin

Answer 10

1. Organisms beget organisms
2. Some variations are heritable
3. More offspring than can be supported by the environment are produced each generation
4. Some individuals have higher fitness than others

Question 11

Punctuated Equilibrium

Answer 11

major change causes branching into new species

Question 12

Speciation requires ____ ____

Answer 12

reproductive isolation

Question 13

3 Types of Natural Selection

Answer 13

Stabilizing selection
Directional selection
Disruptive selection

Question 14

Genetic Variation in Alpine Fish

Answer 14

Movement of cold adapted aquatic species into the headwaters of glacial valleys around the Alps created clusters of geographically isolated populations; Douglas and Brunner used microsattelite DNA to conclude Coregonus populations are highly diverse with high levels of differentiation

Question 15

Hardy Weinberg assumptions

Answer 15

1. Random mating
2. No mutations
3. Large population size
4. No immigration
5. Equal survival and reproductive rates of all genotypes

Question 16

Heritability

Answer 16

evolution through natural selection
h^2 = Vg/Vp = Vg/(Vg+Ve)

Question 17

Evidence of genetic drift in chihuahua spruce

Answer 17

Picea chihuahuana now restricted to peaks of Sierra Madre Occidental in New Mexico;
Ledig et al. examined if species lost genetic diversity as a consequence of reduced population size

Significant positive correlation between population size and genetic diversity

Question 18

For large organisms,
if population <500, __________
if population <50, _________

Answer 18

genetic drift is more likely to happen
inbreeding is more likely to occur

Question 19

Genetic Diversity and Butterfly extinctions

Answer 19

Frankham and Ralls point out INBREEDING contribute to higher extinction rates in small populations

reduced fecundity, depressed juvenile survival, shortened life span

Saccheri et al. studied Glanville fritillary butterflies and found that populations with high inbreeding had high probability of extinction

Question 20

Artificial selection

Answer 20

Selective breeding to produce or maintain desireable traits

Question 21

Genetic engineering

Answer 21

introduction or deletion of genes in organisms; produces GMOs