Question 1

The following questions refer to the evolutionary tree shown 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 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.
 
-Which of the five common ancestors, labelled V-Z, has been least successful in terms of the percentage of its derived species that are extant?

Accepted Answer

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

Question 2

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?

Accepted Answer

A) Larger doses of DDT should have been applied. 
B) All habitats should have received applications of DDT at about the same time. 
C) The frequency of DDT application should have been higher. 
D) None of the individual insects should have possessed genomes that made them resistant to DDT. 
E) DDT application should have been continual.

Question 3

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

Accepted Answer

A) None of the organisms depicted by the tree ate the same foods. 
B) Some of the organisms depicted by the tree had lived in different habitats. 
C) The skeletal remains of the organisms depicted by the tree were incomplete (in other words, some bones were missing). 
D) Transitional fossils had not been found. 
E) Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Question 4

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

Accepted Answer

A) cartilage in the dorsal fin of a shark 
B) bones in the hind limb of a kangaroo 
C) chitinous struts in the wing of a butterfly 
D) bony rays in the tail fin of a flying fish 
E) bones in the flipper of a whale

Question 5

The following questions refer to the description below.
You have read that soapberry bugs, Jadera haematoloma, adapt to available food sources. For example, in southern Florida, soapberry bugs feed on seeds of a native plant, the balloon vine. In central Florida, the balloon vine is rare and soapberry bugs have switched to eating seeds of an introduced species, the goldenrain tree. The seeds of the goldenrain tree fruits are much closer to the fruit surface than the seeds of the native balloon vine fruit. As a result, natural selection results in beaks that are shorter in soapberry bugs that utilize goldenrain tree fruits than those that feed on balloon vine fruit seeds.
-A conservation organization has been trying to eliminate introduced species and encourage the growth/spread of native species. After several years, the balloon vine has almost totally replaced the goldenrain tree in the experimental plot. Based on your knowledge of evolution, which of the following outcomes would appear to be the most logical?

Accepted Answer

A) Half of the soapberry bugs will die. 
B) To save soapberry bugs with short beaks, the researchers must relocate them to a different plot. 
C) Intermediate beak length will be favoured just in case the introduced goldenrain tree makes a comeback. 
D) The genes for short beaks will be lost. 
E) Variation in beak size will remain present in the soapberry bug population, but natural selection will favour beak lengths that are best adapted to the current food source.

Question 6

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

Accepted Answer

A) Technological innovation in agricultural practices will permit exponential growth of the human population into the foreseeable future. 
B) Populations tend to increase at a faster rate than their food supply normally allows. 
C) Earth changed over the years through a series of catastrophic upheavals. 
D) The environment is responsible for natural selection. 
E) Earth is more than 10 000 years old.

Question 7

What is true of pseudogenes?

Accepted Answer

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

Question 8

With what other idea of his time was Cuvier's theory of catastrophism most in conflict?

Accepted Answer

A) gradualism 
B) the fixity of species 
C) island biogeography 
D) uniformitarianism 
E) the scala naturae

Question 9

Which pair of structures best represents convergent evolution?

Accepted Answer

A) the fusiform shape of a shark and a dolphin 
B) the bones in the forelimb of a horse and wing of a bat 
C) the bones in a human arm and flipper of a seal 
D) the tailbone of a human and the tail of a monkey 
E) the wing of a penguin and the wing of an eagle

Question 10

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?

Accepted Answer

A) These genes should continue to be maintained in case the antibiotics ever appear. 
B) These bacteria should be outcompeted and replaced by bacteria that have lost these genes. 
C) The bacteria should try to make the cost worthwhile by locating, and migrating to, microenvironments where traces of antibiotics are present. 
D) The bacteria should start making and secreting their own antibiotics.

Question 11

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

Accepted Answer

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.

Question 12

Charles Darwin was the first person to propose

Accepted Answer

A) that evolution occurs. 
B) a mechanism for how evolution occurs. 
C) that Earth is older than a few thousand years. 
D) a mechanism for evolution that was supported by evidence. 
E) that population growth can outpace the growth of food resources.

Question 13

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?

Accepted Answer

A) homologous; homologous 
B) analogous; homologous 
C) homologous; analogous 
D) analogous; analogous

Question 14

What must be true of any organ that is 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 15

Which of the following criteria is not useful when trying to determine how closely related two types of organisms are?

Accepted Answer

A) DNA sequence data 
B) that both organisms are endemic to the region and utilize the same habitat 
C) developmental stages 
D) homologous structures 
E) vestigial structures

Question 16

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

Accepted Answer

A) All variation between individuals is due only to environmental factors. 
B) The environment is changing at a relatively slow rate. 
C) The population size is large. 
D) The population lives in a habitat where there are no competing species present.

Question 17

A dog breeder of long-haired and long-tailed sheepdogs has decided to select for short fur and short tails in this particular breed. The breeder selects dogs with the shortest fur in each generation and only breeds these dogs. In order to have dogs with short tails, the breeder docks the dogs' tails shortly after birth. After many generations of this artificial selection, you would expect to see which of the following characteristics in the sheepdogs.

Accepted Answer

A) sheepdogs with short fur and long tails 
B) sheepdogs with short fur and intermediate-sized tails 
C) sheepdogs with short fur and short tails 
D) sheepdogs with medium length fur and short tails 
E) sheepdogs with long legs and short tails

Question 18

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

Accepted Answer

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.

Question 19

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

Accepted Answer

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.

Question 20

Ichthyosaurs were aquatic dinosaurs. 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

Accepted Answer

A) homologous. 
B) examples of convergent evolution. 
C) adaptations to a common environment. 
D) Three of the responses above are correct. 
E) Two of the responses above are correct.

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