Genetic Change Genetic Change The gene pool is

Genetic Change

Genetic Change • The gene pool is the total number of different alleles that exist for a population.

Genetic Change • The gene pool is the total number of different alleles that exist for a population. • The processes of mutations, natural selection, migration, and genetic drift all affect the gene pool and change the frequency of the alleles in that gene pool.

Genetic Change • The gene pool is the total number of different alleles that exist for a population. • The processes of mutations, natural selection, migration, and genetic drift all affect the gene pool and change the frequency of the alleles in that gene pool. • Genetic Change therefore refers to the change in frequency of alleles in the gene pool of a population.

Genetic Change • The gene pool is the total number of different alleles that exist for a population. • The processes of mutations, natural selection, migration, and genetic drift all affect the gene pool and change the frequency of the alleles in that gene pool. • Genetic Change therefore refers to the change in frequency of alleles in the gene pool of a population. • Frequency of an allele in a population is given by the formula Frequency of an allele = occurrence of that allele total number of alleles

Genetic Change • The gene pool is the total number of different alleles that exist for a population. • The processes of mutations, natural selection, migration, and genetic drift all affect the gene pool and change the frequency of the alleles in that gene pool. • Genetic Change therefore refers to the change in frequency of alleles in the gene pool of a population. • Frequency of an allele in a population is given by the formula Frequency of an allele = occurrence of that allele total number of alleles

Evolution • The process in which new species develop from earlier forms.

Evolution • The process in which new species develop from earlier forms. • Normally occurs slowly, most often in response to a change in a species’ environment.

Evolution • The process in which new species develop from earlier forms. • Normally occurs slowly, most often in response to a change in a species’ environment. • Life is thought to have evolved from just a few unicellular organisms three billion years ago.

Evolution • The process in which new species develop from earlier forms. • Normally occurs slowly, most often in response to a change in a species’ environment. • Life is thought to have evolved from just a few unicellular organisms three billion years ago. • Evolution happens through ‘changes in the frequency of alleles in a population’ – some alleles do better than others.

Natural Selection • Darwin proposed theory of Natural Selection more than 150 years ago. It remains the best explanation of adaptive evolution.

Natural Selection • Darwin proposed theory of Natural Selection more than 150 years ago. It remains the best explanation of adaptive evolution. • Populations typically produce more offspring than the environment resources can maintain; therefore there is competition for survival.

Natural Selection • Darwin proposed theory of Natural Selection more than 150 years ago. It remains the best explanation of adaptive evolution. • Populations typically produce more offspring than the environment resources can maintain; therefore there is competition for survival. • Individuals with the best adaptations will survive and reproduce (fitness) and pass on to their offspring their successful alleles.

Natural Selection • Darwin proposed theory of Natural Selection more than 150 years ago. It remains the best explanation of adaptive evolution. • Populations typically produce more offspring than the environment resources can maintain; therefore there is competition for survival. • Individuals with the best adaptations will survive and reproduce (fitness) and pass on to their offspring their successful alleles. • The frequency of these alleles will then increase in the gene pool.

Natural Selection • Darwin proposed theory of Natural Selection more than 150 years ago. It remains the best explanation of adaptive evolution. • Populations typically produce more offspring than the environment resources can maintain; therefore there is competition for survival. • Individuals with the best adaptations will survive and reproduce (fitness) and pass on to their offspring their successful alleles. • The frequency of these alleles will then increase in the gene pool. • Environmental factors act as selecting agents of successful phenotypes.

Natural Selection • Darwin proposed theory of Natural Selection more than 150 years ago. It remains the best explanation of adaptive evolution. • Populations typically produce more offspring than the environment resources can maintain; therefore there is competition for survival. • Individuals with the best adaptations will survive and reproduce (fitness) and pass on to their offspring their successful alleles. • The frequency of these alleles will then increase in the gene pool. • Environmental factors act as selecting agents of successful phenotypes. • When environmental factors change, different phenotypes

Natural Selection • If the frequency of alleles changes, evolution is occurring.

Natural Selection • If the frequency of alleles changes, evolution is occurring. • After a certain number of generations, the frequency of the alleles and phenotypes might change so markedly that the population becomes reproductively isolated from other populations of that species – that is the new species.