Lecture 8 Flashcards
T/F
Natural selection and genetic drift lead to divergent populations
true
T/F
gene flow makes populations similar to each other
true
How does gene flow work if a population is separated by a distance
- dispersal of individuals (wind moving pollen, birds eating seeds and flying elsewhere, human transportation)
what does “random” mean in evolution
- mutations
- recombination
- genetic drift
Stochastic
unpredictable or random
Deterministic
predictable
not random
- Natural selection
Genetic drift and its 2 types
GD: stochastic changes in allele frequency due to random variation in fertility and mortality. Affects small populations (fixed homozygosity)
1. Bottleneck
- a single sharp reduction in abundance
- causes alot of diversity loss
2. founders
- a small population colonizes of a new population –> starts a new population
-
T/F
there is lower gene flow with increasing distance
true
- East Africa
Isolation by distance
accumulation of local genetic variation due to geographically limited dispersal
- distance = barrier
Explain the reasons for phenotypic differences between populations within a species
- local adaptions
- genetic drift
- phenotypic plasticity
phenotypic plasticity
a singe genotype to produce different observable traits (phenotype) in response to a particular environment
- can be adaptive or non-adaptive
- modifications of development, growth, behaviour
Reciprocal Transplant Study
seeing the growth of the same genotypes in different environments to compare their performance
- used to figure out if phenotypic variation is genetic or environmental
examples of local adaptations
- skin pigmentation
- darker near the equator
- higher UV radiation - disease resistance
- human height
- lactose tolerance
