Question 1

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that ________.

Accepted Answer

The existence of evolutionary trends, such as increasing body sizes among horse species, suggests that in particular environments, similar adaptations can be beneficial to more than one species. This is known as convergent evolution. It does not necessarily indicate a general trend toward increased complexity or size, nor does it imply that evolution progresses toward a specific goal. A larger volume-to-surface area ratio may be adaptive in many mammals, but this concept is not directly related to the trend of increasing body size in horses.

Question 2

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

The comparison to molluscan eyes suggests that the complex protein assemblage of the prokaryotic flagellum likely arose gradually through a process of natural selection, with ancestral versions of the protein assemblage having less functionality or different functions. This is consistent with evolutionary theory. Option A is incorrect because if the prokaryotic flagellum arose gradually through natural selection, then natural selection must account for its rise. Option C is incorrect because both eyes and flagella have been demonstrated to have evolved through a gradual process of natural selection, and complexity is not a barrier to evolutionary change. Option D is incorrect because it suggests a teleological view of evolution, which is inconsistent with mainstream evolutionary theory.

Question 3

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

This type of genetic change is a change in the spatial organisation of body parts, which is caused by a change in a development gene or its regulation. This is an example of a regulatory change in the Hox gene expression that led to the evolution of tetrapod limbs.

Question 4

Adaptive radiations can be a direct consequence of three of the following four factors. Select the exception.

Accepted Answer

Genetic drift is a random process that can lead to the loss of genetic variation within a population, but it is not a direct cause of adaptive radiation. The other three factors listed - vacant ecological niches, colonisation of an isolated region with suitable habitat and few competitors, and evolutionary innovation - can all directly contribute to adaptive radiations.

Question 5

Many species of snakes lay eggs. However, in the forests of northern Minnesota, where growing seasons are short, only live-bearing snake species are present. This trend toward species that have live births in a particular environment is an example of ________.

Accepted Answer

The trend towards live-bearing snake species in a particular environment is an example of species selection, where certain traits or characteristics become more common in a population over time due to their greater success or advantage in that particular environment. It is not an exaptation (A), which refers to a trait that evolved for one function but later became adapted for a different function, nor is it sexual selection (B), which refers to selection based on traits that increase an individual's chances of mating. Goal direction in evolution (D) is not a recognized scientific concept.

Question 6

Which of the following steps has not yet been accomplished by scientists studying the origin of life?

Accepted Answer

While scientists have been able to create synthetic protocells in the lab, these cells use RNA to direct the polymerization of amino acids rather than DNA. The formation of protocells that use DNA to direct amino acid polymerization has not yet been accomplished.

Question 7

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

RNA could have served as a template for DNA assembly, providing a more stable and accurately replicated molecule, supporting the transition from an "RNA world" to a "DNA world".

Question 8

A female fly, full of fertilised eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly and their balancing organs (halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap.
Which of these fly organs, as they exist in the description, best illustrates an exaptation?

Accepted Answer

The halteres are the best example of an exaptation because they were originally used for balancing during flight but have been modified for use in courtship displays in the daughter species. The vestigial halteres, mouthparts, and eggs do not demonstrate a significant change in function from their original purpose to their current form and function.

Question 9

Fossilised stromatolites

Accepted Answer

Fossilised stromatolites resemble structures formed by bacterial communities that are found today in some shallow marine bays.

Question 10

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

Accepted Answer

Gene duplication events produce multiple copies of a gene, allowing for one copy to continue performing the original function while other copies can mutate and take on new functions. This can lead to novel traits and adaptations, increasing the likelihood of speciation and adaptive radiation. The other choices are not accurate - polyploidy can lead to gene duplication, but not all gene duplications result from polyploidy; the outgroup is a reference point for phylogenetic analysis and is not directly related to adaptive radiation; and while species with less genetic diversity may be more vulnerable to extinction, this is not directly related to the role of gene duplication in prompting adaptive radiation.

Question 11

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.
-Certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This evidence supports the claim that ________.

Accepted Answer

The observation that certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps suggests that natural selection can produce new structures by coupling together parts of other structures. This supports option C as the correct answer. Option A is incorrect because the observation does not necessarily indicate that organs are produced for future environments. Option B is not supported by the evidence presented. Option D is also not supported by the evidence presented.

Question 12

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

The swim bladder is a modified air-breathing organ that has been adapted for a new function (buoyancy control), which is an example of exaptation.

Question 13

Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and suggests a specific order in which this might have occurred. Ancestral cells engulfed and then began to use the metabolic processes of the smaller cells. Based on shared-core processes and features, which statement most accurately describes the order, the theory, and the evolutionary implications for all organisms within domain Eukarya?

Accepted Answer

The endosymbiotic theory suggests that mitochondria were acquired first, providing an advantage in an increasingly aerobic environment, followed by the acquisition of chloroplasts in photosynthetic eukaryotes.

Question 14

Which of the following is a limit of evolution that results in exaptations?

Accepted Answer

Exaptations are traits that evolved for one function but later became useful for a different function. Historical constraints limit the availability of certain traits or variations for natural selection to act upon, which can result in the evolution of traits that are not specifically adapted for their current function but are exapted from previous functions.

Question 15

The oxygen revolution changed Earth's environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere?

Accepted Answer

The evolution of cellular respiration is directly linked to the use of oxygen to harvest energy from organic molecules, which became a fundamental process for most life forms following the increase in atmospheric oxygen. This process allowed organisms to efficiently produce ATP, the energy currency of the cell, using oxygen.

Question 16

Insect wings may have begun to evolve as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air. Additional selection refined them as flight-producing wings. If this hypothesis is correct, modern insect wings would be an example of ________.

Accepted Answer

The hypothesis suggests that insect wings evolved from lateral extensions of the body that were initially used for thermoregulation, and then were exapted for flight. This means that they were co-opted for a new function. Hence, modern insect wings are an example of an exaptation.

Question 17

A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of ________.

Accepted Answer

The swim bladder is believed to have evolved from the lungs of an ancestral fish, but its current function in modern fish is buoyancy control. This is an example of exaptation, which is the process of natural selection co-opting a structure or function for a new purpose.

Question 18

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?

Accepted Answer

India was a separate continent until 45 million years ago, which allowed for unique species to evolve in isolation.

Question 19

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

Accepted Answer

The answer of If one organ is an exaptation of...

Quiz 25: The History of Life on Earth