Question

the weaver birds from the african savanna exhibit a trade-off between risking starvation and being hunted by predators. as a result the birds that are of medium weight have the selective advantage and make up the majority of the population.
which type of natural selection is at work here?
○ directional selection
○ disruptive selection
○ stabilizing selection
done ✔

Explanation:

To determine the type of natural selection, we analyze each option:

• Directional selection favors one extreme phenotype. Here, medium weight (not an extreme) is favored, so this is not it.
• Disruptive selection favors two extreme phenotypes, reducing the intermediate. This is not the case here as medium weight is favored.
• Stabilizing selection favors intermediate phenotypes (like medium weight here) and reduces extreme phenotypes (very light or very heavy birds), which matches the scenario where medium - weight birds have a selective advantage.

Answer:

C. stabilizing selection