What is a bottleneck in population genetics?
A significant reduction in a gene pool leading to lower allele diversity
Bottlenecks can occur due to events like natural disasters or migration, affecting a population’s ability to adapt.
How do bottlenecks affect a population’s genetic diversity?
They reduce allele diversity, making the population more susceptible to environmental stressors
Cheetahs have experienced two bottlenecks, leading to genetic problems.
Define genetic drift.
The random change in allele frequencies in a population over time
Genetic drift is most influential in small populations and can lead to fixation or loss of alleles.
True or false: Genetic drift increases the diversity of alleles in a population.
FALSE
Genetic drift only changes the relative abundance of existing alleles, not their diversity.
What is gene flow?
The movement of individuals and their alleles from one population to another
Gene flow can equilibrate allele frequencies between populations.
What are the three types of nonrandom mating?
- Assortative Mating
- Inbreeding
- Sexual Selection
Nonrandom mating violates the assumption of random mate selection in the H-W model.
What is assortative mating?
Mating with individuals similar (or different) in phenotype
Examples include humans, plants, and certain animal species.
Define inbreeding.
Mating of individuals that share a recent common ancestor
Inbreeding can lead to inbreeding depression, reducing fitness in offspring.
What is inbreeding depression?
Loss of fitness due to increased homozygosity in offspring
It occurs when inbreeding reduces genetic diversity.
What is sexual selection?
A special case of natural selection favoring traits that enhance mate acquisition
It often acts more on males, as females are typically the higher investment sex.
What is female choice in sexual selection?
Females select mates based on traits indicating good alleles or resources
Traits may include health, brightness, and resource availability.
What is male-male competition?
Males compete for mates, often favoring the biggest and strongest individuals
This can lead to sexual dimorphism, where males and females exhibit different traits.
Fill in the blank: Genetic drift is most influential in ______ populations.
small
Small populations are more susceptible to random changes in allele frequencies.
What are the consequences of bottlenecks on cheetah populations?
- Non-random mating
- Small population sizes
- Severe genetic problems
These factors contribute to the decline of cheetah populations.
