Question

the dotted lines represent the population before natural selection acts and the solid lines represent the population after selection acts. most swiss starlings produce four or five eggs each season. those producing fewer or more than this have reduced fitness. which of the graphs above best illustrates how natural selection acts on the number of eggs produced by a swiss starling each season? x w z

Explanation:

Step1: Understand the type of selection

Starlings producing \(4 - 5\) eggs have higher fitness. This is stabilizing selection.

Step2: Analyze each graph

• Graph \(W\): Shows disruptive selection (favors extreme phenotypes).
• Graph \(X\): Shows stabilizing selection (favors intermediate phenotype).
• Graph \(Z\): Shows directional selection (shifts towards one extreme).

Answer:

X