Population and Evolution (complete) Flashcards
(41 cards)
What is population genetics?
The study of genetic variation within populations and the mechanisms that drive changes in allele frequencies.
Define allele frequency.
The number of times an allele occurs within the gene pool.
Define Gene pool
all the alleles of all the genes of all the individuals of a particular population at a given time.
What is the Hardy-Weinberg principle?
A mathematical model that predicts allele and genotype frequencies in a non-evolving population.
The Hardy-Weinberg equation is represented as ______, and _______.
p² + 2pq + q² = 1
p+q=1
What are some causes of change in allelic frequency?
- Predation
- Disease
- Competition
List the conditions required for a population to be in Hardy-Weinberg equilibrium.
No mutations.
Mating is random.
Large population.
No selection.
Isolated population.
What is genetic drift?
A mechanism of evolution that involves random changes in allele frequencies in a population, due to chance.
Occurs in small populations, smaller gene pool so less genetic diversity, so particular genes more likely to be lost.
What effect does Genetic drift have on populations?
- Speciation happens quicker.
- Genes passed on affect allelic frequencies quickly.
What is gene flow?
The transfer of alleles or genes from one population to another.
Name three mechanisms of evolution
genetic drift
mutation
natural selection
Define mutation in the context of population genetics.
A change in the DNA sequence that can introduce new alleles into a population.
What is a bottleneck effect?
A sharp reduction in population size due to environmental events, leading to a loss of genetic diversity.
What is the founder effect?
A reduction in genomic variability that occurs when a small group of individuals become separated from a larger population, resulting in a new subpopulation.
Name the three types of selection
- Disruptive
- Random
- Stabilising
What is stabilizing selection?
A type of natural selection that favors average phenotypes (the mean is selected for) and reduces variation.
Define directional selection.
A mode of natural selection that favors one extreme phenotype over others, shifting the population’s phenotype distribution.
What is disruptive selection?
A type of natural selection that favors extreme phenotypes at both ends of the spectrum, leading to increased variation.
List the factors that can lead to speciation.
Geographic isolation.
Genetic drift.
Natural Selection.
Mutation.
What is reproductive isolation?
A condition that prevents different species from interbreeding and producing fertile offspring.
Define phenotypic variation.
Differences in physical and physiological traits among individuals in a population.
What is allopatric speciation?
- Speciation that occurs due to geographical separation, causing natural selection to occur die to reproductive isolation, forming a new species as the population becomes adapted to the local environment.
What is the role of mutations in evolution?
Mutations introduce new genetic variations that can be acted upon by natural selection.
Name some causes of sympatric speciation.
- Where females lay eggs.
- Different mating seasons.
- Anatomical issues
- Behavioural changes.
