Core P - Selection and Evolution

Question 0

Suggest how deep water rice variety with high yield could be produced using artificial selection. (3)

Answer 0

• Breed deepwater variety of high yielding non-deepwater variety
• Identify and select offspring with both deepwater response and high yield
• Breed selected offspring
• Continue for many generations

Question 1

Outline how artificial selection differs from natural selection. (6)

Answer 1

• Artificial selection:
~ selection pressure by humans
~ genetic diversity lowered
~ inbreeding common
~ loss of vigour (inbreeding depression)
~ increased homozygosity
~ no isolation mechanisms operating
~ faster
~ selected feature for human benefit
~ not for survival or evolution

• Natural selection:
~ environmental selection pressure
~ genetic diversity remains high
~ outbreeding common
~ increased vigour
~ decreased homozygosity
~ isolation mechanisms operate
~ slower
~ selected feature for organism's benefit
~ promotes survival and evolution

Question 2

Explain the role in natural selection in the evolution of antibiotic resistance in bacteria. (3)

Answer 2

• Antibiotic provides selection pressure
• Resistant bacteria live
• Surviving bacteria reproduce
• Pass alleles for resistance to offspring
• Allele frequency increases within the population