Topic 1: Hardy Weinberg Principle

Population

A bunch of the same type of animals or plants living in one place at a specific time.

Genetics

The study of heredity

Species

Groups of creatures that can mate and have babies that can also mate and have babies, which keeps their traits in the same group over time.

Gene Pool

All the genes in all the members of population at one time

• Immigration increases

• Emigration decreases

Evolution

The gradual change in the frequency of genes in a gene pool

• Natural selection is the basis for this

Natural Selection

In nature, certain traits help animals or plants survive better in their surroundings, so those traits become more common over time through survival of the fittest.

Variation Among Organisms

• Physical appearance

• Metabolism

• Fertility

• Mode of reproduction

• Behavior

Population Sampling:

• Select a small sample of ind. from the population

• Find gene frequencies for a particular genetic trait in that sample

• Apply gene frequencies to the whole population

• Allows scientists to analyze trends over time

Hardy-Weinberg Equilibrium

Under specific conditions, after one generation of random mating, gene and allele frequencies (gene pool) will be stable from gen to gen

Conditions of Hardy-Weinberg Equilibrium

• Large population

• Random mating

• No genetic drift

• No gene flow (migrations)

• No natural selection

• No mutations

Alleles Formula

p + q = 1

Genotypes

p² + 2pq + q² = 1

p = A

Frequency of dominant allele in a population

q = a

Frequency of recessive allele in a population

p² = AA

Frequency of homozygous dominant genotype

2pq = Aa

Frequency of heterozygous genotype

q²

Frequency of homozygous recessive genotype