Key Terms
Microevolution
Changes in a population's genetic structure Modern synthesis: unified theory of genetics and evolution; accepted by the
Macroevolution
Broader evolutionary changes observed over paleontological time; new species, major divergence
Population genetics
Study of how selective forces change allele frequencies over time
Allele frequency (gene frequency)
The rate at which a specific allele appears in a population
Formula
Frequency of allele = (copies of that allele) / (all copies of that gene in the population)
Example
If IA appears 26.1% of the time in a population, that is its allele frequency
Gene pool
All alleles carried by all individuals in a population
Genetic variability
Diversity of alleles and genotypes in a population
Heritability
Fraction of phenotypic variation that can be attributed to genetic differences among individuals
Inbreeding
Mating of closely related individuals Inbreeding depression: increased disease and abnormality from inbreeding Macroevol
Mechanism
Rare, deleterious recessive alleles are normally kept at low frequency. Inbreeding dramatically increases the chance tha
Polymorphism
The presence of two or more variations of a characteristic in a population Populations with multiple forms of a trait ar
Selective pressure
An environmental factor that causes one phenotype to be more fit than another
Evolutionary (Darwinian) fitness
An individual's ability to survive and reproduce
Relative fitness
Fitness compared to others in the population Selective pressure: environmental factor causing one phenotype to outperfor