selective breeding

Question 1

define selective breeding

Answer 1

the process by which humans breed plants and animals for specific genetic characteristics, which are often advantageous, through many generations

Question 2

describe selective breeding in animals

Answer 2

1. individuals with the desired characteristics are bred together
2. as a result, the genes for the desired characteristic are passed onto the offspring
3. offspring that best express the desired characteristic are selected and bred together
4. this process is repeated for many successive generations

Question 3

give 2 examples of when selective breeding might be used in animals

Answer 3

• cows, goats and sheep that produce a lot of milk

- chickens that lay large eggs

Question 4

describe selective breeding in plants

Answer 4

1. plant species with the desired characteristics are chosen to cross pollinate and reproduce
2. as a result, the genes for the desired characteristic are passed onto the offspring
3. offspring that best express the desired characteristic are selected and bred together
4. this process is repeated for many successive generations

Question 5

give 3 examples of when selective breeding might be used in plants

Answer 5

• disease resistance in food crops
• increased crop yield
• hardiness to weather conditions

Question 6

describe the problem with selective breeding

Answer 6

selective breeding can cause a reduction in the gene pool (a reduction in the number of different alleles in a population). this can lead to:

• organisms inheriting harmful genetic defects
• organisms being vulnerable to new diseases