Question

part a
which selective pressure is being described in the scenario above?
part b
what effect will this selective pressure have on the population above?
select two answers (one red and one blue)
☐ directional
☐ stabilizing
☐ diversifying
☐ the genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes.
☐ the genetic variation in the population will increase because this pressure leads to the branching of two distinct phenotypic groups.
☐ the genetic variation in the population will not change because no phenotypes have any advantages over the others.

Explanation:

Part A

To determine the selective pressure, we analyze the graphs:

• Directional: Shifts the curve to one side (favors one extreme).
• Stabilizing: Narrows the curve (favors intermediate, reduces extremes).
• Diversifying: Splits into two curves (favors extremes, reduces intermediate).

Assuming the scenario (not fully provided) involves favoring intermediate phenotypes (common for stabilizing), the stabilizing graph (middle one) matches. But since the question is about the selective pressure description, if the scenario has intermediate favored, stabilizing is correct. However, if we assume the standard for Part A (selective pressure type) and Part B (effect):

For Part A, if the effect in Part B mentions intermediate favored (leading to reduced variation), the selective pressure is Stabilizing (red option: Stabilizing).

Part B

• For the blue options:
• "The genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes." matches stabilizing selection (favors intermediate, reduces extremes, so variation decreases).
• "The genetic variation in the population will increase..." is for diversifying (favors extremes, increases variation).
• "The genetic variation... will not change..." is not correct for any of the three selection types.

So the red (selective pressure) is Stabilizing, and the blue (effect) is "The genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes."

Part A Answer:

Stabilizing (the red option labeled "Stabilizing" with its graph)

Part B Answers:

Red: Stabilizing (the red option with the middle graph)
Blue: The genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes. (the blue option with this text)

Answer:

• For the blue options:
• "The genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes." matches stabilizing selection (favors intermediate, reduces extremes, so variation decreases).
• "The genetic variation in the population will increase..." is for diversifying (favors extremes, increases variation).
• "The genetic variation... will not change..." is not correct for any of the three selection types.

So the red (selective pressure) is Stabilizing, and the blue (effect) is "The genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes."

Part A Answer:

Stabilizing (the red option labeled "Stabilizing" with its graph)

Part B Answers:

Red: Stabilizing (the red option with the middle graph)
Blue: The genetic variation in the population will decrease because the intermediate phenotype is being favored over the extreme phenotypes. (the blue option with this text)