In one butterfly species, the colors of individuals range fr…

In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become more and more similar in color over several generations (e.g., if most butterflies are the same shade of gray), what kind of evolutionary force is likely acting on the population?

The fish in a certain population average 10 millimeters in l…

The fish in a certain population average 10 millimeters in length. Imagine that a population of predatory birds arrives in the area, but they cannot eat fish longer than 15 millimeters. After a decade, if the fish average 14 millimeters in length, what probably happened?

 The X-linked varieties of congenital stationary night blind…

 The X-linked varieties of congenital stationary night blindness (CSNB) causes myopia (near sightedness), impaired night vision, reduced visual acuity, and other symptoms. A normal man (whose father has CSNB) marries a normal woman (whose father also has CSNB). If you were only looking at male offspring, what is the chance that a SON will have CSNB? (For the purposes of this question, if there are 2 of the same allele letter, place alleles with a linked trait second.) chance that a SON will have CSNB.