Answer:
1. Definitions:
- Gene: DNA segment carrying trait information.
- Allele: Variant form of a gene.
- Population: Group of interbreeding individuals in an area.
- Gene pool: Complete set of genes in a population.
- Microevolution: Small-scale genetic changes in a population.
- Allele frequency: Proportion of an allele in the gene pool.
- Genotype: Combination of alleles in an individual.
- Phenotype: Observable traits from genotype.
- Homozygous: Having identical alleles for a gene.
- Heterozygous: Having different alleles for a gene.
- Dominant: Trait expressed in the presence of another allele.
- Recessive: Trait expressed only in the absence of a dominant allele.
- Genotype frequency: Proportion of individuals with a specific genotype.
2. Hardy-Weinberg Equilibrium (HW):
- p^2 + 2pq + q^2 = 1 (allele frequency equation)
- p + q = 1 (sum of allele frequencies)
3. Assumptions of HW equilibrium:
- Random mating
- Large population size
- No gene flow
- No mutations
- No natural selection
4. Importance of HW equilibrium:
Though idealized, it serves as a reference for studying evolution and detecting deviations from expected frequencies.
5. Sources of variation:
- Adaptive: Natural selection and non-random mating.
- Non-adaptive: Genetic drift, gene flow, and mutations.
6. Positive patterns of natural selection:
- Directional: One extreme phenotype favored.
- Stabilizing: Intermediate phenotype favored.
- Disruptive: Extreme phenotypes favored.
7. Balancing selection and heterozygote advantage:
- Balancing: Multiple alleles maintained (e.g., sickle cell anemia).
- Heterozygote advantage: Higher fitness for heterozygous individuals (e.g., sickle cell trait).
8. Bottleneck effect and founder effect:
- Bottleneck: Population size drastically reduced.
- Founder: Small group establishes a new population.
9. Assertive mating and inter- / intra-sexual selection:
- Assertive mating: Selection based on similar traits (e.g., selective breeding).
- Intersexual selection: Mating preference based on traits (e.g., peacock tails).
- Intrasexual selection: Competition within a sex for mating access (e.g., antler battles).