EASY
AS and A Level
IMPORTANT
Earn 100

Explain why variation caused by the environment cannot be passed from an organism to its offspring.

Important Questions on Selection and Evolution

MEDIUM
AS and A Level
IMPORTANT

In the classic experiment by Emerson and East, the Black Mexican parents were homozygous at all gene loci affecting cob length. What caused the variation in their cob length?

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EASY
AS and A Level
IMPORTANT
Question ImageIn the table, was the variation in the cob length of the F1 generation caused by genes, environment or both? Explain your answer.
EASY
AS and A Level
IMPORTANT

Question Image

Was the variation in cob length of the F2 generation caused by genes, environment or both? Explain your answer.

EASY
AS and A Level
IMPORTANT

Skomer is a small island off the coast of Wales. Rabbits have been living on the island for many years. There are no predators on the island. 

Rabbits on Skomer are not all agouti. There are quite large numbers of rabbits of different colors, such as black and white. Suggest why this is so.

EASY
AS and A Level
IMPORTANT

Skomer is a small island off the coast of Wales. Rabbits have been living on the island for many years. There are no predators on the island.

Suggest what might be important selection pressures acting on rabbits on skomer.

EASY
AS and A Level
IMPORTANT
A phenotypic trait is controlled by two alleles of a single gene D/d. Explain why only the homozygous recessives, dd, can be recognised?
EASY
AS and A Level
IMPORTANT
Calculate the proportions of homozygous dominant and of heterozygous individuals in a population in which the proportion of homozygous recessives is 16%.
EASY
AS and A Level
IMPORTANT
With reference to the evolution of antibiotic resistance in bacteria, explain the meaning of the term directional selection.