Features with the same function in two organisms but different recent ancestors

As a small change in a person's dna can cause a genetic disorder

Ateam from new york presbyterian hospital is conducting a study about a recent increase in cases involving both excess sweating and kidney stones. what would the team need before it draws a conclusion about the cases? medications that are specifically designed to treat the sickness machines that are built to process blood and reduce symptoms until patients are healthy again data that profile the various patients who report these symptoms proof that the excess sweating is related to the excessive kidney stones

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.