Question

starting in 1945, nets designed to catch the biggest salmon were used in the pacific northwest. as a result, the smaller salmon had an advantage and had a better chance of survival. the small salmon survived to pass on their genes to succeeding generations. which type of natural selection is at work here?
○ directional selection
○ disruptive selection
○ stabilizing selection
done

Explanation:

1. Recall the definitions of each natural selection type:

• Directional selection: Favors one extreme phenotype over others, shifting the population's trait distribution in one direction.
• Disruptive selection: Favors two or more extreme phenotypes, creating a bimodal distribution.
• Stabilizing selection: Favors intermediate phenotypes, reducing variation.

1. Analyze the scenario: The fishing nets target the biggest (one extreme) salmon, so smaller (the opposite extreme) salmon survive and reproduce. This shifts the population's size trait toward smaller sizes, which is directional selection (favoring one extreme, shifting the distribution).

Answer:

A. directional selection