Mastering Biology Chapter 22

Ichthyosaurs were extinct aquatic reptiles distantly related to living lizards. 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

(2 are correct) examples of convergent evolution. homologous. adaptations to a common environment.

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

(2) variation among individuals in reproductive success. genetic variation among individuals. sexual reproduction.

Which term describes a trait that increases an individual's ability to survive in a particular environment?

Adaptation An adaptation is a trait that increases an individual's ability to survive in a particular environment.

Where are the Galapagos Islands located?

600 miles west of Ecuador, near the equator

A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year's crop: Individual A—Yield: 179 bushels/acre; drought resistance: high Individual B—Yield: 220 bushels/acre; drought resistance: low Individual C—Yield: 185 bushels/acre; drought resistance: medium Individual D—Yield: 140 bushels/acre; drought resistance: high Individual E—Yield: 200 bushels/acre; drought resistance: medium Which of the following crosses would produce the highest corn yield with the highest resistance to drought?

A & E

Which of the following organisms could be produced by artificial selection?

A cow that produces a large quantity of milk.

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?

A. The amount of available food may have increased. and C. The number of predators that prey upon squirrels may have decreased.

Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?

All organisms use essentially the same genetic code.

Which of these conditions should completely prevent the occurrence of evolution in a population over time?

All variation between individuals is due only to environmental factors.

Which term describes the ability of a trait to be passed on to offspring?

Heritability Heritability is the ability of a trait to be passed on to offspring.

Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection?

Heritable variation exists for traits among individuals in a population.

Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection?

Individuals experience differential success in their ability to survive or reproduce. Variation in fitness is required for selection to change the characteristics of a population over time. Remember that selection also requires that the variation in fitness be related to a heritable trait.

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

It must be homologous to some feature in an ancestor.

Why did the biologists consider a frog that they found to be a new species?

Its call was unique.

Which pair of chickens should a farmer breed to produce larger chickens?

Large hen, large rooster

Which of the following statements about natural selection is true?

Natural selection favors individuals that reproduce more than others. Individuals who are better able to survive and reproduce are more likely to be selected for than individuals who don't survive or cannot reproduce.

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?

Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.

Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype?

No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host. A cell's drug susceptibility or resistance does not affect its ability to infect another host, although a cell's drug resistance would increase that cell's chances to spread in an environment containing antibiotics due to increased survival.

Based on the video, what can you infer about speciation--the process by which one species splits into two or more species?

Physical separation of populations is often part of the speciation process.

In 1959, doctors began using the powerful antibiotic methicillin to treat infections of Staphylococcus aureus, but within two years, methicillin-resistant strains of S. aureus (MRSA) appeared. How did the resistant strains of S. aureus emerge?

Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common. Evolutionary change comes about as the proportion of individuals in the population displaying a particular trait increases from generation to generation.

Soapberry bugs use needlelike "beaks" to feed on seeds within the fruits of various plants. Bugs feed most successfully when their beak length matches the size of the fruit on which they are feeding. For 25 years, populations of soapberry bugs in central Florida have been feeding on small goldenrain tree fruits that were introduced to the area, rather than on the larger native balloon vine fruits that serve as food for other soapberry bug populations. Beak lengths of soapberry bugs are variable, but the average beak length is shorter in soapberry bug populations that feed on goldenrain tree fruits than in populations that feed on balloon vine fruits, as shown in the graph. How does natural selection act on beak length in soapberry bug populations?

The action of natural selection on beak length in soapberry bug populations varies with the environment. Traits favored by natural selection may change as the environment in which a population lives changes. Selection and adaptation must always be discussed in the context of a particular environment. Soapberry bugs feed most effectively when their beak length closely matches the size of the seed-containing fruit. In central Florida, where soapberry bugs feed on small goldenrain tree fruits, natural selection has reduced average beak length in the population of bugs. However, in Louisiana, where soapberry bugs feed on larger fruits, natural selection has increased average beak length in the population of bugs.

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

The appendix has a substantial amount of defensive lymphatic tissue.

In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer?

The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.

Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment?

The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. Bacterial cells have higher fitness when they are drug resistant in the new environment in which people have been medicated with antibiotics.

A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10% are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?

The proportion of mottled fish will increase over time. The mottled fish will tend to escape predation because they are camouflaged against the mottled lake bottom. The mottled fish will most likely produce more offspring.

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?

The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

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?

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

Which of the following statements best describes theories?

They are supported by, and make sense of, many observations.

True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics.

True In an environment without antibiotics, individual cells probably would not differ in their reproductive rates or their survival. Without the application of the drug (antibiotic), it would be very difficult to analyze any differences—one wouldn't even be able to sort the cells!

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?

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

Which of these lists contains the four postulates of natural selection?

Variation in population, heritable variation, selection, differential survival or reproduction

Which one of the following researchers developed a theory of evolution that was very similar to Charles Darwin's?

Wallace

Charles Darwin was the first person to propose

a mechanism for evolution that was supported by evidence.

An adaptation is _____.

a trait that gives an organism a reproductive advantage in the current environment Evolutionary adaptations are inherited characteristics that enhance an organism's ability to survive and reproduce in a particular environment.

The Galapagos Islands were the first place on Earth to _____.

be declared a world heritage site

Tourism on the Galapagos Islands is being restricted by requiring tourists to _____.

be escorted by trained guides at all times

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

bones in the flipper of a whale

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

by the principle of convergent evolution by identifying the bones as being homologous structures

The role that humans play in artificial selection is to

choose which organisms breed, and which do not.

A challenge to traditional (pre-1860) ideas about species came from embryology, when it was discovered that _____.

embryos of dissimilar organisms, such as sharks and humans, resemble each other Early in development, the similarities among all vertebrate embryos are more apparent than the differences.

The wing of a bat is homologous to the _____ of a whale.

flipper

When Darwin wrote On the Origin of Species, he knew very little about the subject of _____, an essential component of evolutionary theory today.

genetics

Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?

homologous; analogous

Which species is threatening the natural wildlife on the Galapagos Islands?

humans

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

humans and chimpanzees share a relatively recent common ancestor.

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

humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin.

Where are the Solomon Islands located?

in the South Pacific

Natural selection is based on all of the following except

individuals adapt to their environments and, thereby, evolve.

The theory of evolution through natural selection is considered a scientific theory because _____.

it is broad enough in scope to explain many observations it is supported by a massive body of evidence from many disciplines it is general enough to provide many testable hypotheses

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?

selection for larger female algae-eaters, bearing broods composed of more, and larger, young

If two modern organisms are distantly related in an evolutionary sense, then one should expect that

they should share fewer homologous structures than two more closely related organisms.

Which of the following sets of animals are likely to be found on the Galapagos Islands?

tortoises, finches, blue-footed boobies

Scientists studying evolution on the Solomon Islands described which animal as the 'poster child' for the biological species concept?

white-eye bird