BIO 1406 Chapter 22 quiz

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

Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.

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

South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, which develop from similar embryonic tissues. These structural similarities are an example of _____.

homology

From his observations of organisms in the Galapagos islands, Darwin reasoned that _____.

organisms had adapted to new environments, giving rise to new species *Darwin reasoned that natural selection had increased the match between the organisms and their environment.

Charles Darwin _____.

proposed natural selection as the mechanism of evolution *Although Wallace submitted his work for publication first, Darwin's work was known to have pre-dated Wallace's work and was much more detailed; therefore, Darwin was given credit for the theory.

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 survivor ship.

2 → 4 → 1 → 3

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.

Conditions 1 and 2

Identify the pair of homologous structures.

Maple leaf and oak leaf *The common ancestor of maple and oak trees had leaves, and maple and oak leaves have evolved from that ancestral structure. Homologous structures may be quite similar in structure and function (such as maple and oak leaves) or quite different (such as maple leaves and cactus spines).

Which of the following observations led to Darwin's major inferences?

Members of a population vary in their heritable traits. & Although organisms can produce huge numbers of offspring, many of these offspring do not survive.

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

Populations tend to increase at a faster rate than their food supply normally allows.

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics?

These bacteria would be outcompeted and replaced by bacteria that have lost these genes.

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?

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____.

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

Which of the following, if discovered, could refute our current understanding of the pattern of evolution?

diverse fossils of mammals in Precambrian rock

Which of the following must exist in a population before natural selection can act upon that population?

genetic variation among individuals

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 ____.

island forms are descended from mainland forms

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 _____.

mammals evolved from a reptilian ancestor