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