Types of Selection and Speciation

Multiple Choice

Starlings produce an average of 5 eggs in each clutch. If there are more than five, the parents cannot adequately feed the young. If there are fewer than five, predators may destroy the entire clutch. As a result, five eggs became the most common clutch size.

Which pattern of natural selection does this scenario represent?

• Disruptive

• Directional

• Stabilizing

Multiple Choice

Seed cracker birds have either large beaks or small beaks. They do not have medium sized beaks because medium sized beaks do not allow for adequate seed cracking.

Which pattern of natural selection does this scenario represent?

• Disruptive

• Directional

• Stabilizing

Multiple Choice

Green lizards defend themselves from predators by using their tail length to mimic dangerous snakes. Lizards with shorter tails look less like a snake compared to lizards with longer tails. Over time, the lizards with shorter or medium length tails die out.

Which pattern of natural selection does this scenario represent?

• Disruptive

• Directional

• Stabilizing

Multiple Choice

Insects that are camouflaged in their environment are less likely to be eaten by birds.  The graph shows the original distribution of body color in a population of one insect species.

 

The insects live on trees.  A black fungus begins to grow on the trees where the insects live.  Which of the following graphs show the most likely distribution of body color in the insect population after several years of fungus growth?