Question 1

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of ________.

Accepted Answer

A)   the influence of environment on development
B)   paedomorphosis
C)   a change in a developmental gene or its regulation that altered the spatial organisation of body parts
D)   heterochrony C

Question 2

If one organ is an exaptation of another organ, then these two organs ________.

Accepted Answer

A)   are homologous
B)   are undergoing convergent evolution
C)   are found in the same species
D)   have the same function A

Question 3

In 2013, researchers constructed a vesicle with replicated RNA. Why was this significant evidence for abiotic origin of life?

Accepted Answer

A)   RNA molecules could pass on information to their "daughters".
B)   RNA molecules were not able to replicate.
C)   RNA would be used up by protocells.
D)   RNA is a stable repository. A

Question 4

What major innovation of the three radiations was associated with defying gravity to facilitate life on land?

Accepted Answer

A)   stems
B)   waxy covering
C)   insect pollination
D)   new sources of food

Question 5

According to the theory of seafloor spreading, oceanic islands, such as the Hawaiian Islands, form as oceanic crustal plates move over a stationary "hot spot" in the mantle. Currently, the big island of Hawaii is thought to be over a hot spot, which is why it is the only one of the seven large islands that has active volcanoes. What should be true of the island of Hawaii?
I. Scientists in search of ongoing speciation events are more likely to find them here than on the other six large islands.
II. Its species should be more closely related to those of nearer islands than to those of further islands.
III. It should have a rich fossil record of terrestrial organisms.
IV. It should have species that are not found anywhere else on Earth.
V. On average, it should have fewer species per-unit surface area than the other six islands.

Accepted Answer

A)   I, II and III
B)   I, II and V
C)   I, II, III and IV
D)   I, II, IV and V

Question 6

Which of the following is the correct sequence of events in the origin of life?
I. Formation of protocells
II. Synthesis of organic monomers
III. Synthesis of organic polymers
IV. Formation of DNA-based genetic systems

Accepted Answer

A)   I, II, III, IV
B)   I, III, II, IV
C)   II, III, I, IV
D)   II, III, IV, I

Question 7

Which hypothesis for the abiotic formation of organic molecules suggests that early Earth's atmosphere was a neutral atmosphere?

Accepted Answer

A)   The energy for this synthesis could have come from lightning and UV radiation.
B)   Some evidence suggests that the early atmosphere was made up primarily of nitrogen and carbon dioxide.
C)   Amino acids were found near volcanic eruption sites.
D)   Organic compounds were first produced in deep-sea hydrothermal vents.

Question 8

Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in which they eventually pupate. Adult female bagworm moths are larval in appearance; they lack the wings and other structures of the adult male and instead retain the appearance of a caterpillar even though they are sexually mature and can lay eggs within the bag. This is a good example of ________.

Accepted Answer

A)   allometric growth
B)   paedomorphosis
C)   sympatric speciation
D)   adaptive radiation

Question 9

Fossilised stromatolites

Accepted Answer

A)   formed around deep-sea vents.
B)   resemble structures formed by bacterial communities that are found today in some shallow marine bays.
C)   provide evidence that plants moved onto land in the company of fungi around 500 million years ago.
D)   contain the first undisputed fossils of eukaryotes.

Question 10

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of further back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of

Accepted Answer

A)   the influence of environment on development.
B)   paedomorphosis.
C)   a change in a developmental gene or in its regulation that altered the spatial organisation of body parts.
D)   heterochrony.

Question 11

You are the lucky student of a wacko professor who develops a time machine. He asks if you will test it with him. You get in, and there is an immediate glitch-the date readout fails so that when you land, you are not sure what era you are in. As your time machine lands, you see an unusual landscape before you. As you open the door, you realise you cannot breathe. You quickly shut the door, realising you are in the ________.

Accepted Answer

A)   Archaean eon
B)   Cambrian period
C)   Cenozoic era
D)   Mesozoic era

Question 12

If the half-life of carbon-14 is about 5,730 years, then a fossil that has 1/16 of the normal proportion of carbon-14 to carbon-12 should be about how many years old?

Accepted Answer

A)   2,800
B)   11,200
C)   16,800
D)   22,900

Question 13

Which of the following is a defining characteristic that all protocells had in common?

Accepted Answer

A)   the ability to synthesise enzymes
B)   a surrounding membrane or membrane-like structure
C)   RNA genes
D)   the ability to replicate RNA

Question 14

Fossils of Lystrosaurus, a dicynodont therapsid, are most common in parts of modern-day South America, South Africa, Madagascar, India, South Australia, and Antarctica. The animal apparently lived in arid regions and was mostly herbivorous. It originated during the mid-Permian period, survived the Permian extinction, and dwindled by the late Triassic, though there is evidence of a relict population in Australia during the Cretaceous period. Some dicynodonts had two large tusks, extending down from their upper jaws. The tusks were not used for food gathering, and in some species were limited to males. Food was gathered using an otherwise toothless beak. Judging from the fossil record in sedimentary rocks, these pig-sized organisms were the most common mammal-like reptiles of the Permian.
What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?
1) origin of mitochondria
2) origin of multicellular eukaryotes
3) origin of chloroplasts
4) origin of cyanobacteria
5) origin of fungal-plant symbioses

Accepted Answer

A)   4, 3, 2, 1, 5
B)   4, 1, 2, 3, 5
C)   4, 1, 3, 2, 5
D)   4, 3, 1, 5, 2

Question 15

A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from the air-breathing organ (a simple lung) of an ancestral fish is an example of

Accepted Answer

A)   exaptation.
B)   changes in Hox gene expression.
C)   paedomorphosis.
D)   adaptive radiation.

Question 16

What concept explains the evolution of complex eyes?

Accepted Answer

A)   Complex eyes evolved through a series of steps that benefited the eyes.
B)   Mollusc eyes evolved from a different ancestor than vertebrate eyes.
C)   Through evolutionary history, eyes lose function of vision.
D)   Mollusc eye's evolution was dependent on vertebrate eye evolution.

Question 17

The following question is based on the observation that several dozen different proteins comprise the prokaryotic flagellum and its attachment to the prokaryotic cell, producing a highly complex structure.
-If the complex protein assemblage of the prokaryotic flagellum arose by the same general processes as those of the complex eyes of molluscs (such as squids and octopi), then ________.

Accepted Answer

A)   natural selection cannot account for the rise of the prokaryotic flagellum
B)   ancestral versions of this protein assemblage were either less functional or had different functions than modern prokaryotic flagella
C)   neither eyes nor flagella could have arisen by evolution because both are too complex to have evolved
D)   the need for more complex structure must have driven evolution

Question 18

Why would gene duplication events, such as those seen in the Hox gene complex, set the stage for adaptive radiation?

Accepted Answer

A)   There are more copies of genes, meaning speciation had occurred by polyploidy.
B)   The original gene copy is the outgroup, and the new gene copies are the adaptive radiation.
C)   Without duplicated genes, species would be vulnerable to extinction.
D)   One copy of a gene can perform the original function, while other copies are available to take on new functions.

Question 19

One hypothesis that has been proposed regarding the origin of life suggests that life evolved from an "RNA world" to today's "DNA world". Considering the properties of RNA and DNA molecules, which questions would direct an investigation of the most insightful test of this hypothesis?

Accepted Answer

A)   Is it likely that RNA molecules functioned as ribozymes to synthesise DNA from amino acids, and that this role was reversed when DNA became the information source?
B)   Is it likely that simple, yet stable RNA molecules served as a primitive precursor to a less stable DNA molecule that was more capable of storing more information?
C)   Could RNA have provided a template for DNA assembly, thereby enabling a more stable molecule that is replicated more accurately?
D)   Since ribozymes could freely enter and leave the vesicles, could these molecules have brought external DNA into the cell as a less stable, but more reliable storage molecule of double-stranded DNA?

Question 20

Hawaii is the most south-eastern of the seven largest islands and is also closest to the seafloor spreading centre from which the Pacific plate originates, which lies about 5,600 km further to the southeast. Assuming equal sedimentation rates, what should be the location of the thickest sediment layer and thus the area with the greatest diversity of fossils above the oceanic crust?

Accepted Answer

A)   between the island of Hawaii and the seafloor spreading centre
B)   around the base of the island of Hawaii
C)   around the base of Kauai, the oldest of the large Hawaiian islands
D)   where the islands are most concentrated (highest number of islands per unit surface area)

Exam 25: The History of Life on Earth