Exam 19: Descent With Modification

The following questions refer to the evolutionary tree in Figure 19.2. The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V-Z) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. Figure 19.2 -Which pair would probably have agreed with the process that is depicted by this tree?

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (in other words, they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following is least likely to be observed in the algae-eater population over the course of many generations?

Which of Darwin's ideas had the strongest connection to Darwin having read Malthus's essay on human population growth?

Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution?

Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2) A change occurs in the environment. 3) Genetic frequencies within the population change. 4) Poorly adapted individuals have decreased survivorship.

Which of the following observations helped Darwin shape his concept of descent with modification?

If one wanted to find the largest number of endemic species, one should visit which of the following geological features (assuming each has existed for several millions of years)?

In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of

Natural selection is based on all of the following except

Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?

Which of the following is the most accurate summary of Cuvier's consideration of fossils found in the vicinity of Paris?

Which of the following statements most detracts from the claim that the human appendix is a completely vestigial organ?

According to this tree, what percent of the species seem to be extant (in other words, not extinct)?

If Darwin had been aware of genes, and of their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

What is true of pseudogenes?

The following questions refer to Figure 19.1, which shows an outcrop of sedimentary rock whose strata are labeled A-D. Figure 19.1 -Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta and a third species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate phylogenetic tree?

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that