Question

in a bird population, 50 % of the individuals had white feathers, and 50% had colored feathers. over time, it was observed that 98% of the population had colorful feathers. the rest had white feathers. how did the type of selection in this example affect the populations biodiversity?
○ directional selection did not increase the populations biodiversity.
○ stabilizing selection increased the populations biodiversity.
○ disruptive selection decreased the populations biodiversity.
○ ecosystem selection did not increase the populations biodiversity.

Explanation:

1. Analyze selection types:

• Directional selection: Favors one extreme phenotype (here, colorful feathers became dominant, moving from 50% to 98%). This reduces variation (biodiversity) as one trait becomes more common.
• Stabilizing selection: Favors intermediate phenotypes, reducing extremes (not the case here as one trait became dominant).
• Disruptive selection: Favors two extremes, increasing biodiversity (opposite of what happened).
• Ecosystem selection is not a standard natural selection type.

1. Evaluate options:

• First option: Directional selection (favoring colorful feathers) reduced variation, so it did not increase biodiversity. This matches.
• Second option: Stabilizing selection would not increase biodiversity here (and the scenario is not stabilizing).
• Third option: Disruptive selection would increase, not decrease, biodiversity (incorrect).
• Fourth option: Ecosystem selection is not a valid natural selection category for this context.

Answer:

A. Directional selection did not increase the population's biodiversity.