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

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

A) humans and chimpanzees share a relatively recent common ancestor.
B) humans evolved from chimpanzees.
C) chimpanzees evolved from humans.
D) convergent evolution led to the DNA similarities.
E) humans and chimpanzees are not closely related.




Answer: A

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?

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?

A) Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.
B) Forelimb evolution was adaptive in people and bats, but not in whales.
C) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
D) Genes mutate faster in whales than in humans or bats.
E) Whales are not properly classified as mammals.



Answer: C

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?

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?

A) S. aureus can resist vaccines.
B) A patient must have become infected with MRSA from another community.
C) In response to the drug, S. aureus began making drug-resistant versions of the protein targeted by the drug.
D) Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.
E) The drug caused the S. aureus DNA to change.



Answer: D

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

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

A) Species diversity declines farther from the equator.
B) Fewer species live on islands than on the nearest continents.
C) Birds can be found on islands located farther from the mainland than the birds' maximum nonstop flight distance.
D) South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.
E) Earthquakes reshape life by causing mass extinctions.



Answer: D

Which of the following is not an observation or inference on which natural selection is based?

Which of the following is not an observation or inference on which natural selection is based?

A) There is heritable variation among individuals.
B) Poorly adapted individuals never produce offspring.
C) Species produce more offspring than the environment can support.
D) Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited.
E) Only a fraction of an individual's offspring may survive.



Answer: B

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

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 Pinaroloxias. 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

A) remain in the genus Camarhynchus.
B) be switched from Camarhynchus to Certhidea.
C) be switched from Camarhynchus to Pinaroloxias.
D) be switched from Camarhynchus to Geospiza.
E) be placed in its own genus.



Answer: E

According to a 1999 study, the vegetarian finch is genetically no more similar to the tree finches than it is to the ground finches, despite the fact that it is placed in the same genus as the tree finches. Based on this finding, it is reasonable to conclude that the vegetarian finch

According to a 1999 study, the vegetarian finch is genetically no more similar to the tree finches than it is to the ground finches, despite the fact that it is placed in the same genus as the tree finches. Based on this finding, it is reasonable to conclude that the vegetarian finch

A) is no more closely related to the tree finches than it is to the ground finches, despite its classification.
B) should be re-classified as a warbler finch.
C) is not truly a descendent of the original ancestral finch.
D) is a hybrid species, resulting from a cross between a ground finch and a tree finch.



Answer: A

If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

A) They should be limited to the six islands that most recently emerged from the sea.
B) Their genomes should be more similar to each other than are the genomes of the five tree finch species.
C) They should share fewer anatomical homologies with each other than they share with the tree finches.
D) The chances of hybridization between two ground finch species should be less than the chances of hybridization between two tree finch species.



Answer: B

Evolutionary trees such as this are properly understood by scientists to be

Evolutionary trees such as this are properly understood by scientists to be

A) theories.
B) hypotheses.
C) guesses.
D) dogmas.
E) facts.



Answer: B

Which pair would probably have agreed with the process that is depicted by this tree?

Which pair would probably have agreed with the process that is depicted by this tree?

A) Cuvier and Lamarck
B) Lamarck and Wallace
C) Aristotle and Lyell
D) Wallace and Linnaeus
E) Linnaeus and Lamarck



Answer: B

Which of the five common ancestors, labeled V-Z, has been most successful in terms of the percent of its derived species that are extant?

Which of the five common ancestors, labeled V-Z, has been most successful in terms of the percent of its derived species that are extant?

A) V
B) W
C) X
D) Y
E) Z



Answer: E

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?

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) V
B) W
C) X
D) Y
E) Z


Answer: B

Which of the five common ancestors, labeled V-Z, has given rise to the greatest number of species, both extant and extinct?

Which of the five common ancestors, labeled V-Z, has given rise to the greatest number of species, both extant and extinct?

A) V
B) W
C) Z
D) Both W and Z can be considered to have given rise to the greatest number of extant and extinct species.
E) Both X and Y can be considered to have given rise to the greatest number of extant and extinct species.




Answer: E

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

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

A) 25%
B) 33%
C) 50%
D) 66%
E) 75%


Answer: D

How many separate species, both extant and extinct, are depicted in this tree?

How many separate species, both extant and extinct, are depicted in this tree?

A) two
B) three
C) four
D) five
E) six



Answer: E

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?

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?

A) one stratum
B) two strata
C) three strata
D) four strata


Answer: B

If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?

If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?

A) A
B) B
C) C
D) D



Answer: C

A high degree of endemism is most likely in environments that are

A high degree of endemism is most likely in environments that are

A) easily reached and heterogeneous.
B) isolated and heterogeneous.
C) isolated and homogeneous.
D) isolated and extremely cold.
E) easily reached and homogeneous



Answer: B

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)?

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) an isolated ocean island in the tropics
B) an extensive mountain range
C) a midcontinental grassland with extreme climatic conditions
D) a shallow estuary on a warm-water coast



Answer: A

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

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

A) island forms and mainland forms descended from common ancestors.
B) common environments are inhabited by the same organisms.
C) the islands were originally part of the continent.
D) the island forms and mainland forms are converging.
E) island forms and mainland forms have identical gene pools.



Answer: A