Microevolution Flashcards
What is microevolution?
Small scale evolution, changes in allele and genotype frequencies, departure from hardy weinberg equilibrium
Adaptive Cause of Equilibrium: Natural Selection
If a trait is selected for or against the allele/genotype frequencies change. Only adaptive cause of equilibrium, selective pressure
Modes of natural selection
Stabilizing selection, directional selection, diversifying selection
Stabilizing selection
Extreme phenotypes selected against. Graph is thinner and taller
Directional selection
One extreme phenotype selected for the other against, graph moves right or left. Most common
Diversifying selection
Favors extreme phenotypes over intermediate forms. Patchy environments. Graph moves toward both sides not middle. Least common.
What is a mutation?
Change in DNA sequence which can cause a change in amino acid sequence. Different protein can lead to a different trait.
When does mutation occur?
DNA replication
Is a mutation beneficial?
Occasionally but most mutations are harmful or benign.
When is mutation heritable?
When it occurs in germ line cells
What is introduced through mutation?
New alleles
What is gene flow?
Gene pools are affected by migration. Individuals move into or out of populations or populations combine.
What is genetic drift?
A population is established by or decreased to a small number of individuals. Individuals aren’t perfectly representative of the original larger population.
What is the bottleneck effect?
Large percent of a population is filled by a non selective event.
What is founder effect?
Small number of individuals colonize new habitat. Sampling error
