What is genetic diversity?
The variety and number of different alleles in a population of a species
What 3 things affect genetic diversity?
- Genetic Bottlenecks
- The founder effect
- Artificial Selection
What causes genetic diversity?
Variation in DNA base sequences coding for different proteins
What is a genetic bottleneck?
A catastrophic event that causes a reduction in population of more than 50%
What is the founder effect?
A small founder population colonises a new habitat
What is artificial selection?
Certain alleles are specifically selected and other disadvantageous ones are deselected
What are the effects of a genetic bottleneck?
- Population size is greatly reduced
- Genetic diversity is reduced
- Population is less likely to have individuals that can adapt to changes in the environment
- Inbreeding occurs to re-establish previous population size
- This maintains the already reduced genetic diversity
What is the result of the founder effect?
- Genetic diversity is reduced
- Founders will be less likely to adapt to environmental changes
- Founders disproportionately represent the total number of alleles
- Genetic drift
What is a disadvantage to plants that are selectively bred?
- They are out competed by wild plants and are very susceptible to drought
What is a disadvantage to animals that are selectively bred?
- Have certain alleles perpetuated
- certain alleles such as the alleles for genetic disorders could be perpetuated
What are some advantages of selective breeding?
- Food is cheaper
- Food is of a higher quality
- Production costs for food are kept down
Define genetic diversity
The variety of different genes / alleles in a population / species
Explain why organisms of the same species show genetic diversity even though they have the same genes?
Same species contain different alleles of a specific gene and therefore exhibit genetic diversity
Why is genetic diversity important?
- The greater the genetic diversity the greater the variety of alleles in a population
- So there is more likely to be an organism suited to the environment
- So it is more likely an organism will be capable of adapting to changes in the environment
What determines how large the genetic diversity is within a population?
The number of alleles in a population
