Question

Long necks make it easier for giraffes to reach leaves high on trees, while also making them better fighters in "neck wrestling" contests. In both cases, which kind of selection appears to have made giraffes the long-necked creatures they are today?

a. Stabilizing selection
b. Disruptive selection
c. Directional selection

Answer 1

c. Directional selection

Step-by-step explanation:

Directional selection is a type of natural selection that occurs when selective pressure favors one extreme phenotype over any other phenotype existing in a population. Only one extreme phenotype is favored over time.

A good example of directional selection is the natural selection that occurs in giraffes, where alleles for long necks were favored against alleles for short necks as a result of selection pressure among the different phenotypes. Over time, giraffes having long necks dominated the population as the distribution of length of neck shifts towards the phenotype for long necks.