Unit 3, Part 6 Flashcards
What are the three types of frequencies that can be calculated in population genetics?
Phenotypic, genotypic, and allelic frequencies.
What are the assumptions of the Hardy-Weinberg principle?
- Large population size
- No mutation
- No migration
- Random mating
- No selection.
What does it mean for a population to be in Hardy-Weinberg Equilibrium (HWE)?
Allele frequencies remain constant over generations.
List the 4 forces that act on populations affecting allele frequencies.
- Mutation
- Migration (gene flow)
- Genetic Drift
- Selection.
What is the impact of mutation on a population?
Adds genetic variation, can lead to advantageous, deleterious, or neutral changes.
What is required for a mutation to be passed to offspring in sexually reproducing organisms?
The mutation must occur in gametes.
True or False: A brand-new mutation typically has a large effect on allele frequencies from one generation to the next.
False.
What is gene flow?
Movement of individuals or their gametes between populations.
What is genetic drift and when does it have a stronger effect?
Random changes in allele frequency, stronger in small populations.
What is a bottleneck event?
A significant reduction in population size due to an event, leading to a loss of genetic variation.
Define the founder effect.
When a small group of individuals establishes a new population, leading to reduced genetic variation.
What is fitness in the context of natural selection?
An organism’s ability to pass its genetic material to its offspring.
List the types of natural selection.
- Directional
- Stabilizing
- Diversifying.
What is the selection coefficient (sc)?
The intensity of selection against a genotype, calculated as sc = 1 - W.
Fill in the blank: Non-random mating alone doesn’t change ______ in the population.
allele frequencies.
What is inbreeding?
Mating between individuals that are closely related.
What is the problem associated with inbreeding?
Inbreeding depression, which decreases fitness.
What is outbreeding (outcrossing)?
Mating between individuals that are less closely related.
What are the two types of reproductive isolating mechanisms?
- Prezygotic
- Postzygotic.
What is allopatric speciation?
Speciation that occurs due to geographical isolation.
Define sympatric speciation.
Speciation that occurs without geographical isolation, often through reproductive isolation mechanisms.
What does a phylogenetic tree represent?
Evolutionary relationships among organisms or genes.
What do terminal nodes in a phylogenetic tree represent?
Currently existing species.
What does cladogenesis refer to?
When one group splits into two or more lineages, leading to new species.
