Genetic diversity
- Created by: Laura
- Created on: 17-04-14 10:55
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- Genetic Diversity
- Organisms are varied. Over 1.8 million species of organisms have been identified. Every species is different.
- The greater the number of different alleles that all members of a species possess, the greater the genetic diversity of that species
- The greater the genetic diversity of a species, the more likely it will be to be able to adapt to some environmental change.
- Selective Breeding
- Selective breeding is also known as artificial selection. It involves identifying individuals with the desired characteristic and using them to parent the next generation
- Offspring that do not exhibit the desired characteristic are killed or at least prevented from breeding
- Alleles for unwanted characteristics are bred out of the population
- The variety of alleles in a population is deliberately restricted to a small number of desired alleles. Reduces genetic diversity
- Usually used to produce high yielding breeds of domesticated animals and strains of plants
- The Founder Effect
- The founder effect occurs when just a few individuals from a population colonies a new region
- These few individuals will carry with them only a small fraction of the alleles of the population as a whole. These alleles may not be representative of the general population
- The new population that develops will therefore show less genetic diversity than the population from which it came
- The founder effect is usually seen when new volcanic islands rise out the sea. The new population in time may form a new species.
- As the new species has fewer alleles it is less able to adapt to its environment
- Genetic Bottlenecks
- Populations form time to time may suffer a dramatic drop in numbers. Sometimes the reason for this drop is a chance event, such as a volcanic eruption
- The few survivors will possess a much smaller variety of alleles than the original population - the genetic diversity will be less
- As these few individuals breed and become re-established, the genetic diversity of the new population will remain restricted
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