Bio 51-75 Flashcards
What can be used to test whether a population is evolving?
The Hardy-Weinberg equation.
What is the condition in which allele frequency remains constant in a population from generation to generation?
Hardy-Weinberg equilibrium
What symbolizes the frequency of the dominant allele in the Hardy-Weinberg equation?
p
What symbolizes the frequency of the recessive allele in the Hardy-Weinberg equation?
q
p + q =
1
What symbolizes the frequency of the homozygous dominant genotype in the Hardy-Weinberg equation?
p2
What symbolizes the frequency of the heterozygous genotype in the Hardy-Weinberg equation?
2pq
What symbolizes the frequency of the homozygous recessive genotype in the Hardy-Weinberg equation?
q2
What is the Hardy-Weinberg equation?
p2 + 2pq + q2 = 1
p2 + 2pq + q2 =
1
What will happen to allele and genotype frequencies if a population is in Hardy-Weinberg equilibrium?
Remain constant generation after generation.
What 5 conditions must be met for a population to stay in Hardy-Weinberg equilibrium?
Very large population, no gene flow, no mutations, random mating, no natural selection.
What are the 3 main causes of microevolution in a population of sexually reproducing organisms?
Natural selection, genetic drift, and gene flow.
Why is mutation not one of the main causes of microevolution in a population of sexually reproducing organisms?
Too rare of an event. However, mutation can be a main cause of evolution in prokaryotes.
Why is nonrandom mating not one of the main causes of microevolution in a population of sexually reproducing organisms?
Scientists have rarely seen this one without at least one of the other main causes.
What is the process in which chance events can cause allele frequencies to fluctuate unpredictably from one generation to the next?
Genetic drift
What size population is affected by chance events, i.e., genetic drift?
small
What produces a small population through the kill of most of the individuals (catastrophes, hunting, habitat destruction?
Bottleneck effect
What produces a small population through a few individuals colonizing an island or other remote habitat?
Founder effect
What is the process by which a population may gain or lose alleles when fertile individuals (or just gametes in the case of pollen) move into or out of a population?
Gene flow
What is the only mechanism that leads to adaptive evolution?
Natural Selection
Natural selection is often described as survival of the fittest. Who are the fittest individuals in the context of evolution?
Those that leave the most offspring.
What outcome of Natural Selection shifts the overall makeup of the population by acting against individuals at one of the phenotypic extremes?
Directional Selection
What outcome of Natural Selection favors intermediate phenotypes, i.e. selects against both extremes?
Stabilizing Selection
