Exam 22: Descent with Modification: A Darwinian View of Life

Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?

With what other idea of his time was Cuvier's theory of catastrophism most in conflict?

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

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

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?

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, then what should happen in environments from which antibiotics are missing?

What was the prevailing belief prior to the time of Lyell and Darwin?

Which of the following statements best describes theories?

What must be true of any organ that is described as vestigial?

Natural selection is based on all of the following except

DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that

The rise of methicillin-resistant Staphylococcus aureus (MRSA)can be considered to be an example of artificial selection because

Charles Darwin was the first person to propose

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. Thus, which statement should be true?

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)?

A 14th species that descended from the original ancestral finch, the Cocos Island finch, is endemic to its namesake island, located 550 km off Costa Rica. The Cocos Island finch is genetically much more similar to the tree finches than is the vegetarian finch, yet it is classified in its own genus Pinarolaxias. Moreover, the Cocos Island finch and the vegetarian finch are the two finch species that are most genetically different from the ancestral Galápagos finch. Thus, if classification is to reflect evolutionary relationships, the vegetarian finch should

The following questions refer to Figure 22.1, which shows an outcrop of sedimentary rock whose strata are labeled A-D. Figure 22.1 -If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?

The following questions refer to the evolutionary tree in Figure 22.2. 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 22.2 -Which of the five common ancestors, labeled V-Z, has been least successful in terms of the percent of its derived species that are extant?

A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of both competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. Which inference(s)about this population might be true?