Northern foxes can have different fur colors.

Question

The foxes hunt squirrels for food. Foxes that have fur the same color as their environment are better at getting closer to squirrels and catching them.

Diagram titled Population Before contains 2 rows of fox icons. The first row is labeled Brown and contains 3 fox icons. The second row is labeled Gray and contains 7 fox icons.
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A population of foxes once lived in an environment where there was not very much snow. The image above shows what the population looked like then. The environment changed so it is now very snowy.

The diagrams below show two predictions for what the population could be like after many generations.

Diagram titled Prediction 1 (Many Generations Later) contains 3 rows of fox icons. The first row is labeled Brown and contains 2 fox icons. The second row is labeled Gray and contains 2 fox icons. The third row is labeled White and contains 9 fox icons.
Diagram titled Prediction 2 (Many Generations Later) contains 2 rows of fox icons. The first row is labeled Brown and contains 2 fox icons. The second row is labeled Gray and contains 10 fox icons.
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8. Which prediction best shows what the population could look like after many generations? What caused it to change?
Responses

a
Prediction 1 is best. Two brown or gray foxes had a baby with a mutation in its genes for the white-fur trait. Because white foxes are more likely to survive, that baby survived long enough to pass on its mutation, so the white-fur trait became more common over generations.
Prediction 1 is best. Two brown or gray foxes had a baby with a mutation in its genes for the white-fur trait. Because white foxes are more likely to survive, that baby survived long enough to pass on its mutation, so the white-fur trait became more common over generations.

b
Prediction 1 is best. White foxes are more likely to survive, so brown and gray foxes began to have offspring with mutations in their genes for the white-fur trait so that their offspring would have a better chance of surviving.
Prediction 1 is best. White foxes are more likely to survive, so brown and gray foxes began to have offspring with mutations in their genes for the white-fur trait so that their offspring would have a better chance of surviving.

c
Prediction 2 is best. A fox could have been born with a mutation in its genes for the white-fur trait and lived for a little while. Because white foxes are more likely to die, it would have been more likely to die before it had offspring, so the final population will only have brown and gray foxes.
Prediction 2 is best. A fox could have been born with a mutation in its genes for the white-fur trait and lived for a little while. Because white foxes are more likely to die, it would have been more likely to die before it had offspring, so the final population will only have brown and gray foxes.

d
Prediction 2 is best. A fox could have been born with a mutation in its genes for the white-fur trait, but having a mutation in its genes would have caused it to die when it was born, so the final population will only have brown and gray foxes.

Answer 1

The best response to your question about which prediction shows what the population could look like after many generations, along with the reasoning behind the change, is:

a Prediction 1 is best. Two brown or gray foxes had a baby with a mutation in its genes for the white-fur trait. Because white foxes are more likely to survive, that baby survived long enough to pass on its mutation, so the white-fur trait became more common over generations.

This option correctly identifies that the change in population dynamics is due to the advantages of having white fur in a snowy environment, leading to increased survival rates for individuals with that trait. Over generations, this trait can become more common in the population through natural selection.