Evolution

Question 1

What are the types of natural selection? (6)

Answer 1

Directional selection (1)

• Alleles for extreme phenotype likely selected triggered by environment change (1)
• Graph shifts to the right (1)

Stabilising selection (1)

• Alleles for average phenotype likely selected as environment is stable (1)
• Graph becomes more pointed (1)

Question 2

What is genetic drift? (2)

Answer 2

• Change in allele frequency by chance rather than environment (1)
• Greater effect in smaller populations (1)

Question 3

What is genetic bottleneck? (2)

Answer 3

• Population is greatly reduced (1)
• Allele frequency in gene pool decreases, creating a new population with lower genetic diversity (1)

Question 4

What are the assumptions of the harvey weinberg principle? (3)

Answer 4

• Population is large (1)
• Random mating (1)
• No new mutations (1)

Question 5

Pros and cons of selective breeding? (2)

Answer 5

Pros = Desirable characteristics (1)

Cons = Loss of alleles compromises adaptability (1)

Question 6

What are the types of speciation? (4)

Answer 6

Allopatric speciation:

• Organisms geographically isolated from each other (1)

Sympatric speciation:

• Organisms reproductively isolated from each other by mutation (1)