3.4.4 Genetic Diversity and Adaptation

Define genetic diversity

The number of alleles of genes in a species or population

Define population

The number of organisms of the same species, in the same area at the same time, that are able to inter read

How can genetic diversity be increased

By mutations and gene flow

Why is high genetic diversity beneficial to a population

It enables natural selection to occur

Describe the process of natural selection

Random mutations occur in a new allele for a gene, new allele increases chances of survival, advantageous allele is inherited over generations, frequency of the new allele increases

Describe differential reproductive success

A new allele increasing chances of survival of survival for that individual

What does natural selection result in

Species better adapted to their environment

Define anatomical adaptations

Physical adaptation such as fur and ears

Define behavioural adaptations

Adaptations on the behaviour of organisms, such as hibernating

Define physiological adaptations

Adaptations biochemically, such as poison and tanning

Describe directional selection

One extreme phenotype allele is favoured and selected for

Give an example of directional selection

Antibiotic resistance in bacteria

Describe stabilising selection

The medium phenotype allele is selected for

Give an example of stabilising selection

Birth Weight

Describe divergent selection

Both extreme phenotypes alleles are selected for

Give an example of divergent selection

Black and white moths

What can divergent selection lead to

Speciation and therefore evolution

What do mutations result in

Generations of new alleles contributing to genetic diversity or the gene pool

Why can alleles have no affect on an organism

The genetic code is degenerate