Individual Ecology Flashcards
1
Q
What is evolution?
A
- a change over time of the proportions of individual organisms differing genetically in one or more traits
- a change in allele frequency in a population over time
2
Q
What is natural selection?
A
- the differential survival and/or reproduction of organisms that differ in one or more characteristics
3
Q
What are the criteria for natural selection?
A
- variation in population
- variation must be heritable
- some variants, on average, must have higher survivorship or more offspring that others
4
Q
What are ecotypes?
A
- locally adapted and genetically distinct populations
5
Q
What is directional selection?
A
- natural selection favors an extreme phenotype over others in a population
6
Q
What is stabilizing selection?
A
- natural selection against extreme phenotypes and favors an average one
7
Q
What is disruptive selection?
A
- natural selection favors two or more extreme phenotypes over average ones
8
Q
What is heritability (h^2)?
A
- the proportion of total phenotypic variation in a trait that can be attributed to genetic variance
9
Q
What is the equation for heritability? What do the variables mean?
A
- h^2 = Vg / Vp; where h^2 = heritability, Vg = genetic variance, and Vp = total phenotypic variance
10
Q
What is the equation for total phenotypic variance? What do the variables mean?
A
- Vp = Vg + Ve; where Vp = total phenotypic variance, Vg = genetic variance, and Ve = environmental factors
11
Q
What happens when Vg = 0?
A
- h^2 = 0
- phenotype is due to environment and won’t be passed on (i.e. tattoos)
12
Q
What happens when Vg = 0.5?
A
- h^2 = 0.5
- phenotype is due to both genetic and environment (i.e. adult height)
13
Q
What happens when Vg = 1?
A
- h^2 = 1
- phenotype is due to genetics and will be passed on (i.e. blood type)
14
Q
What is genetic drift?
A
- randomly occurring changes in allele frequency over time
15
Q
Why is genetic drift important to small populations?
A
- can reduce genetic diversity
- can lead to differentiation
