James wants to estimate the absolute age of an animal fossil. However, test results show that the fossil doesn’t contain any atoms of carbon-14. What can James conclude about the lack of carbon-14? A. The animal, whether living or dead, never had carbon-14 in its system. B. The animal’s carbon-14 decayed long before the animal died. C. Finding another fossil nearby without carbon-14 will guarantee that he has matching fossils. D. Without carbon-14, it will be an impossible task to estimate the age of the fossil. E. Without carbon-14, James can use relative dating to estimate the age of the fossil.

For a to be healthy, it has to have lots of different kinds of plants and animals. all of the different types of plants and animals in an ecosystem. name four types of ecosystems from those listed in the video. b) c) d) most living things live here. all living things depend on how an ecosystem like a game of sticks? why should we build new buildings on existing land? name four extinct species from those listed in the video. b) c) d) the best way to wipe out a species is to the largest ecosystem in the world is this percent of the world is covered by water. how many of all species in the world live in the ocean? list five things you can do to increase biodiversity. b) c) d) e) how many species are we losing per hour?

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.

Up until 1938, paleontologists accepted the idea that coelacanths (an ancient fish) went extinct at the time that they last appear in the fossil record, about 80 million years ago. but in 1938, a live coelacanth was discovered off the coast of south africa that was compared to the fossil record and found to be the same species what goal of science does this discovery represent