Allopatric speciation
where a population forms a new species while being geographically isolated from its parent population
Sympatric Speciation
where a subset of a population forms a new species without geographic separation
Directional Selection
it shifts the overall makeup of the population by favoring variants that are at one extreme of the distribution.
Disruptive Selection
it favors variants at both ends of the distribution
Stabilizing Selection
it removes extreme variants from the population and preserves intermediate types.
Genetic Drift
it is a chance events that alter allele frequencies from one generation to the next in a population, especially in a small population.
Founder Effect
it is where a few individuals become isolated from a larger population and establish a new population whose gene pool differs from the source population
Bottleneck effect
it is a severe drop in population size resulting in certain alleles being overrepresented, underrepresented, or not represented at all
Gene Flow
the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes
Gene
coding for a particular trait
Allele
different variations of a gene
Gene Pool
sum of genes within a population
Genotype
genetic make-up, alleles present on your chromosome
Homozygous
having the same allele for a gene
ex. AA, aa
Heterozygous
having different alleles for a gene (dominant allele will be expressed)
ex. Aa
Homozygous Dominant
having the dominant alleles
ex. AA
Homozygous Recessive
having the recessive alleles, only expressed when they are homozygous
ex. aa
Phenotype
the visual characteristics that are being expressed
Hardy-Weinberg Theorem
- Population is not changing/evolving
- Population is n ever true in nature
- Population can estimate how far off the populations are
- Population can investigate why not at equilibrium
Equation for Allelic Frequency in a Population
p + q = 1
p – frequency of dominant allele
q - frequency of recessive allele
Equation for Genotypic Frequency in a Population
p^2 + 2pq + q^2= 1
p2 – frequency of homozygous dominant
2pq - frequency of heterozygous
q2 – frequency of homozygous recessive