natural selection

Natural Selection

Organisms with traits better-suited to their environment survive and reproduce more often (This causes traits to change over time).

Adaptation

A trait that helps a population survive (Giraffe's long neck).

Population

A group organisms of the same species living in a particular area at the same time

struggle for existence

Not all organisms can survive in a population due to environmental pressures and competition

Genetic Variation

Organisms have different genes and traits caused by mutation

differential survival and reproduction

The best adapted to their environment are likely to have many offspring that survive.

evolution

the change in the gene pool (allele frequencies) of a species over time

mutation

the process in which DNA changes result in new alleles

selective pressure

environmental conditions that select for certain characteristics of individuals and select against other characteristics

Result of natural selection

Can lead to evolution

Can lead to new variations

Mutation

Alleles

Alternate form of a gene

One Mechanism of Evolution

Natural selection

selective advantage

The circumstance that enables survival and reproducuction of a certain organism in a population in a given environment

p

dominant allele frequency

q

recessive allele frequency

p2

frequency of homozygous dominant genotype

2pq

frequency of heterozygous genotype

q2

homozygous recessive frequency