U5 Ch2 - Bio, Selective breeding

What are the 5 purposes of selective breeding?

• Improbe temperament

• Alter appearance

• Increase milk or meat yield

• Increase crop yield

• Disease ressitance

Why does natural selection take long time periods?

There will be a small population, breeding with individuals of unfavourable characteristics

• Select the plants with the least bitter flavour

• Breed them together

• Select offspring with the least bitter flavour

• Breed them together

• Repeat

What are the problems with selective breeding?

Can lead to inbreeding ( only animals with the ‘best’ characteristics, that are closely related are bred), resulting in a reduction in the gene pool. This is a reduction in the number of alleles (different versions of a gene), less biodiversity

What are the disadvantages of a limited gene pool?

• Organisms are at risk of inheriting genetic defects

• Organisms vulnerable as there is less chance of resistance ( less alleles present so there’s less chance of resistance alleles in the genes(