5) you are in the field studying two species of tanager, the western tanager and the summer tanager. you notice that the male birds are brightly colored and do an elaborate dance to attract females. the males do not appear to be picky; they court females of both species. the females, however, only respond to the males of their own species; they never mate with males of the other species. you then catch 10 males and 10 females of each species and bring them back to the lab. in the lab, after some persuasion (barry white and a nice bottle of wine), you successfully mate male western tanagers to female summer tanagers. when the eggs hatch, all of the offspring are male, no female chicks came of the hybridization. what type of prezygotic barrier to gene flow is this? what type of postzygotic barrier?

In order to clone adult animals, scientists typically begin with a(n)

Rease is an enzyme used by plants to break down urea (a nitrogen-containing compound) into carbon dioxide and ammonia. urease urea > > > carbon dioxide and ammonia ammonia is broken down by plants into a nitrogen source plants need to grow. thus, plants could not use urea as a nitrogen source unless it was first converted to ammonia. in soybean plants there are two different kinds of urease, one produced in the seeds and the other produced in the leaves of the plant. three types of soybean plants were used in a set of experiments: normal soybeans and two mutant strains, one lacking the urease in the seeds only (strain 1) and one lacking urease in the leaves only (strain 2). experiment 1 separate areas in a field were planted with normal, strain 1, and strain 2 soybeans. all types of soybeans appeared to grow, flower, and produce seeds equally well. there were no externally detectable differences among the strains. experiment 2 small pieces of plant leaves of equal weight were obtained from each type of soybean plant and separately placed on media in culture dishes. tissue growing in this way will become an unorganized clump of cells referred to as callus. to provide a controlled nitrogen source, half the tissue samples of each type were placed on media containing urea, and the other half of the samples were placed on media containing ammonia. after 30 days, the weight gain for each of the callus samples was determined. results are shown in the table below.

Which label correctly identifies what x represents in the concept map?