1. Darwin's finches vary in size from 10-20 cm and 8-38 g. Warbler-finches are the smallest species of them all. At some time in history, which selection led to their evolution?

2. In the large cactus finch, some males have shorter beaks and other males have
longer beaks. Which type of selection probably operated on this species?
18.2

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.

Select all that apply. why are common names not a good reference to a species? common names can be in different languages common names vary with location common names vary with culture common names vary with species color

Abiologist counts the number of rabbits in a population each year and observes a decrease in population. since the coyote population has exploded, the biologist concludes that the coyote population has had a negative interaction with the rabbit population. which describes the biologist’s actions? a.) experimentationb.) inferencec.) observationd.) interacting