Natural selection. darwin hypothesized that there requisites for natural selection to occur and that there are definite steps to natural selection. note the two models seen here. both of the models illustrate an important requisite for natural selection. that is: a) sexual reproduction must occur. b) survival of the fittest is untrue. c) variation in the population exists. d) genetic sameness reduces the chances of natural selection.

Which of the following is not a characteristic of carnosaurs? a. long narrow skulls b. strong forelimbs c. horn projecting from their skulls d. none of the above

Read the following scenario to answer the following question. over the past 60 years, many amphibian species have experienced significant population declines, and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. when most populations of a wide-ranging amphibian species are lost and the few remaining populations are widely separated, we expect to see that a. the founder effect becomes increasingly important b. microevolution no longer occurs c. gene flow between populations is reduced d. artificial selection becomes a greater factor in microevolution

You can tell from this karyotype that the individual is female because the karyotype has two chromosomes labeled