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• Super Challenge:

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Key Questions:

1. What are the impacts of selective breeding of food plants and domesticated animals?
   • Selective breeding will lead to narrowing of the gene pool. This means that potential future diseases could be more problematic as a larger percentage of the population would be affected. Selective breeding would also reduce variety in the future and could lead to problems relating to recessive genes.
2. What is selective breeding and how long have humans been doing it?
   • Selective breeding (artificial selection) is the process by which humans breed plants and animals for particular genetic characteristics. Humans have been doing this for thousands of years since they first bred food crops from wild plants and domesticated animals.
3. How do humans carry out selective breeding?
   • Selective breeding involves choosing parents with the desired characteristic from a mixed population. They are bred together. From the offspring those with the desired characteristic are bred together. This continues over many generations until all the offspring show the desired characteristic.
4. Why are certain characteristics chosen during selective breeding? What are some examples of these in plants and animals?
   • The characteristic can be chosen for usefulness or appearance: ? Disease resistance in food crops. ? Animals which produce more meat or milk. ? Domestic dogs with a gentle nature. ? Large or unusual flowers.
5. What disadvantages can selective breeding have?
   • Selective breeding can lead to ?inbreeding? where some breeds are particularly prone to disease or inherited defects.
6. What evidence is there to support Darwin's theory of evolution?
   • Evidence for Darwin's theory is now available as it has been shown that characteristics are passed on to offspring in genes. There is further evidence in the fossil record and the knowledge of how resistance to antibiotics evolves in bacteria.