Chapter 14: Non-adaptive Evolution And Speciation Flashcards
(18 cards)
What is a gene pool?
A gene pool is the total collection of alleles in a population.
Genetic diversity of a gene pool is critical for the survival of populations.
What are the main evolutionary mechanisms that influence the composition of a gene pool?
Natural selection, mutation, genetic drift, and gene flow.
Natural selection is adaptive, while mutation, genetic drift, and gene flow are nonadaptive forms of evolution.
How does the gene pool of an evolving population compare to that of a nonevolving population?
The Hardy-Weinberg principle describes the frequency of alleles and genotypes in a nonevolving population. When a population does not fit with Hardy-Weinberg predictions, it is evolving.
What causes changes in allele frequency in populations?
Natural selection and nonadaptive evolution.
Nonadaptive evolution includes random changes due to mutation, genetic drift, and gene flow.
What is genetic drift?
Random changes in the allele frequencies of a population between generations.
The smaller the population, the greater the effect of genetic drift.
What is the founder effect?
A type of genetic drift in which a small number of individuals leaves one population and establishes a new one.
What is the bottleneck effect?
A type of genetic drift that occurs when a population is suddenly reduced to a small number of individuals.
Why is genetic diversity important?
It gives a population more flexibility to survive in a changing environment.
What is gene flow?
The movement of alleles from one population to another.
What is inbreeding?
Mating between closely related individuals.
Inbreeding does not change the allele frequency within a population but increases the proportion of homozygous individuals.
What is inbreeding depression?
Negative reproductive consequences for a population associated with a high frequency of homozygous individuals possessing harmful recessive alleles.
What are the five necessary conditions for Hardy-Weinberg Equilibrium?
- No mutation creating new alleles
- No natural selection favoring some alleles over others
- Infinitely large population size
- No influx of alleles from neighboring populations
- Random mating of individuals
What is the biological species concept?
A population of individuals whose members can interbreed and produce fertile offspring.
What is reproductive isolation?
Mechanisms that prevent mating between different species, leading to no zygote formation.
What is speciation?
Genetic divergence of populations leading to reproductive isolation and the formation of new species.
Fill in the blank: The Hardy-Weinberg equation is ______.
p² + 2pq + q² = 1
What are the components of the Hardy-Weinberg equation?
- p² is the frequency of homozygous dominants
- 2pq is the frequency of heterozygotes
- q² is the frequency of homozygous recessives
True or False: Genetic drift can increase genetic diversity.
False
