Question 1

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

Accepted Answer

A)  Species diversity declines further from the equator. 
B)  Fewer species live on islands than on the nearest continents. 
C)  Birds live on islands located further from the mainland than the birds' maximum nonstop flight distance. 
D)  Australian temperate plants are more similar to Australian tropical plants than to the temperate plants of Europe.

Question 2

Which of the following factors could cause a surge in population size?

Accepted Answer

A)  a decrease in available food 
B)  an increase in the number of predators 
C)  better eyesight evolves in the population 
D)  decreased camouflage evolves in the population

Question 3

What must be true of any organ described as vestigial?

Accepted Answer

A)  It must be analogous to some feature in an ancestor. 
B)  It must be homologous to some feature in an ancestor. 
C)  It must be both homologous and analogous to some feature in an ancestor. 
D)  It need be neither homologous nor analogous to some feature in an ancestor.

Question 4

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the pigweed reappeared?

Accepted Answer

A)  The herbicide company lost its triazine formula and started selling poor-quality triazine. 
B)  Natural selection caused the pigweed to mutate, creating a new triazine-resistant species. 
C)  Triazine-resistant pigweed has less-efficient photosynthesis metabolism. 
D)  Triazine-resistant weeds were more likely to survive and reproduce.

Question 5

Given what we know about evolutionary biology, we expect to find the largest number of endemic species in which of the following geological features, which have existed for at least a few million years?

Accepted Answer

A)  an isolated ocean island in the tropics 
B)  an extensive mountain range 
C)  a grassland in the centre of a large continent, with extreme climatic conditions 
D)  a shallow estuary on a warm-water coast

Question 6

Which of the following statements describe evolution?

Accepted Answer

A)  Individuals evolve in response to their environment. 
B)  The match between organism and their environment decreases. 
C)  Natural selection chooses the most popular trait. 
D)  Quick changes occur in an individual's phenotype.

Question 7

What are adaptations?

Accepted Answer

A)  geologic changes over time 
B)  rocks containing fossils 
C)  inherited characteristics of organisms that enhance their survival 
D)  descent with modification from a common ancestor

Question 8

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?

Accepted Answer

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

Question 9

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?

Accepted Answer

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

Question 10

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

Accepted Answer

A)  was the first theory to refute the ideas of special creation 
B)  proved that individuals acclimated to their environment over time 
C)  dismissed the idea that species are constant and emphasised the importance of variation and change in populations 
D)  was the first time a biologist had proposed that species changed through time

Question 11

Darwin used the phrase "descent with modification" to explain ________.

Accepted Answer

A)  unity of life 
B)  descent of all organisms from a single, ancient ancestor 
C)  that habitat differences stimulate change in organisms 
D)  evolution of the unity and diversity of life

Question 12

Which statement illustrates the connection between natural selection and overreproduction of a population?

Accepted Answer

A)  Populations vary in their inherited traits. 
B)  Species produce more offspring than can survive in the environment. 
C)  Individuals with inherited traits that promote survival tend to have more surviving offspring. 
D)  Individuals with traits that do not enhance survival cannot reproduce.

Question 13

Currently, two of the living elephant species (X and Y) are placed in the genus Loxodonta, and a third surviving species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate phylogenetic tree?

Accepted Answer

A) 
 
B) 
 
C) 
 
D)

Question 14

Pseudogenes are ________.

Accepted Answer

A)  composed of RNA, rather than DNA 
B)  the same things as introns 
C)  unrelated genes that code for the same gene product 
D)  nonfunctional vestigial genes

Question 15

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?

Accepted Answer

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

Question 16

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 labelled 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 ________.

Accepted Answer

A)  groups of living organisms 
B)  groups of extinct organisms 
C)  the most recent common ancestor of the subsequent branches 
D)  morphologic gaps in the fossil record

Question 17

About 13 different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

Accepted Answer

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 hybridisation between two ground finch species should be less than the chances of hybridisation between two tree finch species.

Question 18

Fossils found in strata reveal that ________.

Accepted Answer

A)  older strata carry fossils that differ greatly from living organisms 
B)  geologic changes occur quickly on Earth 
C)  unused body parts decrease in size 
D)  innate drive to complexity of life

Question 19

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

Accepted Answer

A)  The ability of individuals to survive and reproduce is not equal. 
B)  There is variation in inherited traits. 
C)  Individuals who reproduce more leave more offspring. 
D)  The unequal ability to reproduce leads to the accumulation of favourable traits in a population.

Question 20

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

Accepted Answer

A)  These genes would be maintained in case the antibiotics appear. 
B)  These bacteria would be outcompeted and replaced by bacteria that have lost these genes. 
C)  These bacteria would try to make the cost worthwhile by locating and migrating to microenvironments where traces of antibiotics are present. 
D)  The number of genes conveying antibiotic resistance would increase in these bacteria.

Exam 22: Descent With Modification: a Darwinian View of Life