A bird that preys on moths is introduced to the habitat with moths and trees like the ones shown below. A white moth and a black moth are shown.

What will most likely happen to the population of moths in this habitat?

a) The population of moths will eventually become extinct.
b) The moths will evolve from dark to light due to a selective pressure.
c) The dark colored moths will experience disruptive selection.
d) The alleles that determine light and dark color in moths will equalize.

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

Why do we perceive objects as retaining their brightness under different lighting levels?

1. fold your hands together so your thumbs cross over ,and look at your thumbs. which thumb feels most "comfortable" on top is actually controlled by a gene. the left thumb folding over the right thumb is a domi