Researchers grew populations of identical Escherichia coli (E. coli) bacteria in a growth medium that contained a low concentration of glucose and a high concentration of citrate, a substance that is not typically consumed by E. coli. For thousands of generations, the bacteria used only glucose as an energy source and grew relatively slowly and to a low density because of the low concentration of glucose. After about 30,000 generations, one population emerged that began to rapidly grow to a much higher density. The researchers hypothesized that the bacteria evolved the ability to use citrate as an energy source and referred to them as Cit . To test the hypothesis, the researchers grew separate populations of the Cit bacteria and bacteria from the original population (Cit- ) in a growth medium that contained only citrate. Describe one outcome that would demonstrate that a given population has evolved.

Can you identify which of the following groups of organisms are, or are not, populations? a. the american bison (bison bison) and grey wolves (canis lupus) currently living in yellowstone national parkb. all of the rainbow trout (oncorhynchus mykiss that) that have ever lived in lake eriec. the group of american bison (bison bison) currently living in yellowstone national parkd. a group of calliope hummingbirds (selasphorus calliope) and a group of rufous hummingbirds (selasphorus rufus) living in the same new hampshire woodse. the northern cardinals (cardinalis cardinalis) living on opposite shores of lake champlain f. all of the whales currently living in the atlantic ocean off cape cod, massachusetts

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

Determine if the following statement is true or false. if true, choose true. if false, choose the rewording that is true. according to the law of independent assortment, alleles for each gene are inherited together so that they always stay together. according to the law of independent assortment, offspring express a combination of their parents' traits. according to the law of independent assortment, alleles for a characteristic split during meiosis and combine during fertilization. true according to the law of independent assortment, alleles for each gene are inherited independently so that no two alleles stay together.