AQA Biology Unit 2: 9 Genetic Diversity

• Similarities and differences between organisms can be defined in terms of variation of DNA
• DNA difference leads to genetic diversity

Selective Breeding

• Also known as artificial selection
• It uses the desired characteristics from one animal
• Offspring are produced with the desired characteristic
• If the offspring doesn't have the characteristic it can be killed or stopped from breeding
• Alleles for unwanted characteristics are bred out
• Selective breeding reduces genetic diversity
• It is carried out to produce high yield plants or animals

The Founder Effect

• When few individuals from a population colonise a new region
• The individuals have few alleles
• When the colony repopulate they have less genetic diversity
• In time the population may develop into a separate species
• They are less adapt to changing conditions since they have fewer alleles

Genetic Bottleneck

• Natural disasters can cause this
• The survivors will possess smaller variety of alleles then original population
• When repopulating the genetic diversity will remain restricted
• The fewer alleles mean they are less adapt to change in conditions