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

Currently, two extant elephant species (X and Y)are classified in the genus Loxodonta, and a third species (Z)is placed in the genus Elephas. Thus, which statement should be true?

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.

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

Scientific theories ________.

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

Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been warm-blooded. The fossils of Thrinaxodon are consistent with the hypothesis that ________.

Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following would suggest that the relationship more likely represents homology instead of convergent evolution?

The questions below refer to the following evolutionary tree, in which the horizontal axis represents time (present time is on the far right) and the vertical axis represents morphological change. -Which of these is the extant (that is, living)species most closely related to species X?

Over long periods of 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?

Which of the following statements best explains why modification or change in an organ or tissue during the lifetime of an individual is not inherited?

Pseudogenes are ________.

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

Which of the following statements describe evolution?

The following questions refer to the evolutionary tree in the figure below. 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. -Which of the five common ancestors, labeled V-Z, is the common ancestor of the greatest number of species, both living and extinct?

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits must increase reproductive success. Condition 3: Individuals pass on most traits that they acquire during their lifetime.

Which one of the following observations did Darwin first make during his discovery of evolution?

The following questions refer to the evolutionary tree in the figure below. 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. In Darwin's tree of life, each fork in the tree represents ________.

Within six months of effectively using methicillin to treat S. aureus infections in a community, all new S.aureus infections were caused by MRSA. How can this best be explained?

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

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?