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:

• Directional selection: Favors one extreme phenotype. Here, colored feathers (an extreme compared to the initial 50 - 50 split) became more common (98%). Biodiversity (measured by the variety of feather - color phenotypes) decreased as one phenotype (colored) dominated.
• Stabilizing selection: Favors the intermediate phenotype. But in this case, there is a shift to one extreme, so it's not stabilizing selection.
• Disruptive selection: Favors both extreme phenotypes. But here only one extreme (colored) is favored.
• Ecosystem selection is not a standard type of natural selection in evolutionary biology.

Answer:

Directional selection did not increase the population’s biodiversity.