4.6.2.3 Selective Breeding

Question 1

Selective breeding / artificial selection:

Answer 1

the process by which humans breed plants and animals in order to produce offspring with particular genetic characteristics / certain desirable characteristic(s)

Question 2

How does selective breeding take place?

Answer 2

• parents with desired characteristics are chosen from a mixed population
• they are bred together
• from the offspring those with the desired characteristic are bred together
• this process is repeated many times and continues over many generations until all the offspring show the desired characteristic

Question 3

What characteristics are animals/plants selectively bred for?

Answer 3

• disease resistance in food crops
• animals which produce more meat or milk
• domestic dogs with a gentle nature
• large or unusual flowers

Question 4

What is a problem with selective breeding?

Answer 4

• can lead to inbreeding where some breeds are particularly prone to disease or inherited defects
• breeding those with similar desirable characteristics means it is likely you are breeding closely related individuals
• this results in the reduction of the gene pool - as the number of different alleles reduce as they mostly have the same alleles
• also if the environment changes or there is a new disease, the species could become extinct as they all have the same genetic makeup - so the chance of a few organisms having a survival advantage and not dying is reduced