Selective Breeding: Answers

Give examples of desirable features which could be chosen for selective breeding.

Organisms can be selectively bred for features such as high yield (of meat, milk, grain or fruits), resistance to disease, higher nutritional content and calm temperament.

A farmer wants to breed cows which produce a lot of milk. Explain how he could use selective breeding to improve the milk yield from his cows.

The farmer would choose the cow which produces the largest amount of milk and breed this with a bull. The offspring produced would be assessed and the ones which produce the most milk will be chosen and bred together. This is repeated over several generations and milk yield should gradually increase.

What are some of the disadvantages of selective breeding?

Selective breeding produces organisms which are genetically similar so they will be equally vulnerable to the same diseases. It can also result in the loss of alleles (types of a gene) which makes it difficult to produce different varieties of certain organisms in the future.

Compare the process of selective breeding (artificial selection) with natural selection.

Natural selection is the process by which organisms with the most suitable characteristics to their environment are more likely to survive and reproduce, passing on the genes for these characteristics onto the next generation. Therefore, the environment (or nature) is what ‘selects’ the characteristics and it is a natural process. In selective breeding, humans select the characteristics and it is an artificial process.