What is a mutation?
Any change in the genetic sequence that can be inherited by offspring.
Define natural selection.
The process where some genetic variants replicate faster and contribute more to the next generation, leading to adaptation.
What is genetic drift?
Random changes in allele frequencies due to chance events in finite populations.
What are the assumptions of the Hardy-Weinberg equilibrium?
Diploid individuals, infinite population size, no selection, no mutation, random mating, no migration.
What is heterozygote advantage?
When heterozygotes have higher fitness than either homozygote.
What is the C-value paradox?
Genome size does not correlate with organismal complexity.
Explain polyphenic traits.
A single genotype can produce multiple phenotypes depending on the environment.
What is the difference between broad-sense heritability and heritable?
Broad-sense heritability is the proportion of phenotypic variance due to genetics; heritable means a trait can be passed from parent to offspring.
What is the selection differential (S) in quantitative genetics?
The difference between the mean trait value of selected individuals and the mean of the whole population.
Give an example of disruptive selection in nature.
Beak size variation in Galapagos finches where extreme sizes are favored over intermediate sizes.
What is the founder effect?
When a small number of individuals establish a new population, causing reduced genetic variation.
What is the difference between germline and somatic mutations?
Germline mutations are heritable and occur in gametes; somatic mutations affect body cells and are not heritable.
Define allele frequency.
The proportion of a specific allele in a population.
What is the effect of bottlenecks on genetic variation?
Temporary reduction in population size reduces genetic variation and can increase inbreeding.
Explain negative frequency-dependent selection.
Rare phenotypes are favored because their fitness decreases as they become more common.
What is recombination and how does it affect evolution?
Shuffles alleles during sexual reproduction, creating new combinations but not new variation.
What is a quantitative trait locus (QTL)?
A genomic region associated with variation in a quantitative trait.
What is the breeder’s equation (R = h^2 S) used for?
Predicting the response to selection based on heritability and selection differential.
Explain stabilizing selection using gall flies as an example.
Intermediate gall sizes are favored because birds eat large galls and wasps attack small galls.
What is inbreeding depression?
Reduced fitness in a population due to increased homozygosity of deleterious alleles.
What is the effect of population size on the efficacy of natural selection?
Selection is more effective in large populations and less effective in small populations.
Define polygenic traits.
Traits influenced by many genetic loci.
Explain how Fisher’s experiment with Qβ virus illustrates natural selection.
Faster-replicating viral lineages were selected in vitro, leading to increased replication rate and genome reduction.
How does artificial selection differ from natural selection?
Artificial selection is human-directed for desired traits, while natural selection is driven by environmental pressures.
