Research suggests that selective breeding began about 10000 years ago. Selective breeding has been important in satisfying the global demand for food.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2023). The mark or mark type is shown in brackets.

1. [1] (a) select plants (resistant to disease) / AW;
2. [1] (a) by exposing plants to disease to show resistance ;
3. [1] (a) breed (selected plants with resistance);
4. [1] (a) plant seeds/grow offspring;
5. [1] (a) select offspring with resistance and breed together;
6. [1] (a) (repeat for) many generations ;
7. [1] (a) AVP; e.g. named wheat disease / rust disease / mildew disease
8. [1] (b) reduction in genetic variation / gene pool made smaller / decrease in heterozygosity / increase in homozygosity ; I loss of biodiversity
9. [1] (b) less hybrid vigour ;
10. [1] (b) inbreeding depression ;
11. [1] (b) harmful recessive alleles could, come together/ be expressed;
12. [1] (b) (population) susceptible to, environmental change / new disease ;
13. [1] (b) AVP; e.g. disadvantageous traits occur / reduced fertility / susceptible to metabolic disorders