- The population suffers a dramtic drop in numbers due to a chance event such as a natural disaster or human inteference.
- The survivors possess a smaller variety of alleles than the original population = not representative.
- This means their genetic diversity will be less.
- As the survivors become re-established, the genetic diversity of the new population will be restricted.
- Less diversity means fewer alleles, making it less likely that the population can adapt to changes in its environment.
The Founder Effect
- Occurs when a few individuals of a popualtion move and colonise a new area.
- These individuals only carry with them a small representation of the populations alleles as a whole.
- The new population develops therefore shows less genetic diversity than the original population.
- The few individuals that colonise new areas often breed popualtions that are genetically distinct from the population they left behind.
- The new population may, in time, develop into a seperate species.
- This species has fewer alleles and are less likely to be able to adapt to changing environments.
Selective Breeding (Artificial Selection)
- Identifying individuals with the desired characteristics and using them to parent the next generation.
- Offspring without the desired characteristics are not used to breed.
- In this way the alleles for unwanted characteristics are bred out of the population.
- The alleles of the population are deliberately restricted to a small number of desired ones.
- Over many generations this leads to a population that possess the desired characteristics but reduced genetic diversity.
- Scientific research requires funding and the outcome may be influenced depending on who gives the funding e.g. farms, government, animal welfare group or supermarkets.
- The personal, moral and religious beliefs of the scientist may affect the experiments they preform.
- The development of new species is not happening naturally and are only being bred for the use of humans.
- It enables people to select the features they desire which could extend to other pets, when people select the features of their pet for appearance.
- The breeding of animals may have an affect on global warming if the animals produce a lot of methane.
- Consumerism is forcing us to produce more food at cheap prices.
- Selective breeding methods are still artificial - can be seen as playing God.
- There is a large impact on animal welfare and how the genetic changes affect the animals lives and whether the animals are being bred humanely or are being caged and abused.
- Restricting the alleles of species could lead to the loss of alleles that could benefit humans and animals in the future.
Genetic diversity refers to the variety of genes possessed by the individuals that make up any one species.
Similarities and differences between organisms are defined in terms of variation in DNA.
The differences in DNA lead to the vast genetic diversity we have on Earth.