Question

generation 1
generation 5
generation 10
■beak x
■beak y
■beak z
the graphs above show a change in distribution of beak phenotypes x, y, and z over 10 generations. notice that beak x completely disappears from the population by generation 5, but reappears by generation 10. could this occur in nature? how?
○ yes, the alleles for beak x could remain in the population as a recessive gene.
○ yes, the birds could mutate their beaks in response to a change in the environment.
○ yes, genetic mutation is so frequent that beak x will likely reappear randomly by generation 10.
○ no, once birds with beak x are extinct, they cannot appear again.
done

Explanation:

To determine the correct answer, we analyze each option:

• Option 1: Recessive alleles can be hidden in a population (e.g., heterozygous individuals) and reappear when conditions allow (e.g., two carriers mating). This matches how traits can disappear and reappear.
• Option 2: Birds don't "mutate their beaks" in response to environment; mutations are random, not directed responses. Eliminate.
• Option 3: Genetic mutations aren't so frequent that a specific trait like Beak X would randomly reappear by Generation 10. Recessive alleles being hidden is more plausible. Eliminate.
• Option 4: Traits can reappear if alleles remain (e.g., recessive), so "cannot appear again" is wrong. Eliminate.

Answer:

A. Yes, the alleles for Beak X could remain in the population as a recessive gene.