Question 1

Natural selection

Accepted Answer

Natural selection is the principle cause of evolutionary change, as it leads to the adaptation of organisms to their environment over time. It is not the principle cause of extinctions, which can also be caused by factors such as habitat destruction or climate change. Natural selection operates on phenotypic variation, which arises from genetic variation within a population, and is not dependent on genetic drift. It can affect all cells in an organism, not just gametes.

Question 2

Bears have thinner bones than whales.Hippopotami have intermediate bone thickness.What hypothesis does this support?

Accepted Answer

The fact that bears have thinner bones than whales, while hippopotami have intermediate bone thickness, supports the hypothesis that hippopotami spend part of their time living in water and part living on land. This explains why their bones are neither as thick as the fully aquatic whales nor as thin as the fully terrestrial bears.

Question 3

Cultivation of corn over thousands of years has resulted in a modern corncob that looks very different from the tiny ancestral cob.Does this support the concept of evolution?

Accepted Answer

Artificial selection is a form of evolution where humans select for desirable traits, demonstrating that species can change over time, similar to natural selection.

Question 4

Natural selection tends to

Accepted Answer

Natural selection favors traits that enhance survival and reproduction, leading to an increase in the frequency of those traits within a population. This process can ultimately lead to the commonality of those traits in a given population. Natural selection does not necessarily decrease the number of individuals in a population or increase genetic drift, and it actually promotes adaptation rather than decreasing the likelihood of it.

Question 5

Peppered moths are generally light in color and blend into the trunks of the trees they live on.Populations of peppered moths found in areas where soot has blackened the tree trunks are dark in color.This example demonstrates

Accepted Answer

The example of peppered moths in areas with soot shows natural selection at work. The darker moths are able to blend in better with their environment and have a better chance of surviving and reproducing, passing on their dark coloration genes to future generations.

Question 6

The result of ________ over evolutionary time spans is that alleles that allow organisms to survive and reproduce at a higher rate than other individuals become more common in the population.

Accepted Answer

The process described in the question involves the natural selection of advantageous alleles. These alleles lead to increased survival and reproduction, allowing them to become more common in the population over time. Artificial selection involves intentional selective breeding by humans, homology refers to the similarity between different species due to shared ancestry, and gene flow is the movement of genes between different populations.

Question 7

Neanderthal fossils

Accepted Answer

Neanderthal fossils are likely to be found in layers below human fossils, as they lived before Homo sapiens and are not direct ancestors.

Question 8

Humans simulate the process of natural selection when they use ________ to develop new varieties of crop plants that better meet the needs of farmers.

Accepted Answer

The process of artificially selecting certain individuals with desirable traits and breeding them together to create a new variety of crop plant is a form of artificial selection. This mimics the process of natural selection, where certain traits become more prevalent in a population over time due to their advantageous nature. Gene flow, habitat changes, and continental drift do not directly relate to the development of new crop varieties through intentional human selection.

Question 9

Which of the following statements about evolution is true?

Accepted Answer

Evolution can result in the addition or loss of traits in existing organisms, depending on the selective pressures and environmental factors at play. Both processes can contribute to the overall diversity and adaptation of a species over time. Therefore, statement A and B are both incorrect, and statement D is completely false.

Question 10

Breeding programs for farm-raised chickens result in a variety of unusual colors and feathers.Is this an example of evolution?

Accepted Answer

The change in chicken coloration is a genetic change that is occurring in the population over time, which is a form of evolution. This change is a result of human-driven selective breeding programs that favor certain traits, such as unusual colors and feathers. Although the changes are occurring in domesticated animals, they still represent evolution in action. Option A is incorrect because domesticated animals can undergo evolution. Option B is incorrect because evolution can be observed over relatively short periods of time, depending on the species and the environmental pressures they face. Option C is incorrect because the selective breeding programs are not driven by natural selection, but rather by human preferences.

Question 11

A group of scientists proposed that mammals with fur that contrasts with their background are hunted more by predators than mammals with fur that blends in with their background.After running several experiments,the scientists found that dark mice were attacked 25 percent of the time in a dark habitat and 75 percent of the time in a light habitat.The light colored mice were attacked 25 percent of the time in a light habitat and 75 percent of the time in a dark habitat.These data

Accepted Answer

The data support the hypothesis because it shows that dark-colored mice were attacked more in light environments, while light-colored mice were attacked more in dark environments. This suggests that the mice with fur that contrasts with their background (i.e. dark in a light environment or light in a dark environment) are more likely to be hunted by predators.

Question 12

The fossil record

Accepted Answer

The fossil record provides evidence that major new groups of organisms arose from previously existing organisms through the process of evolution. It shows transitional forms between different species and demonstrates the gradual evolution of organisms over time. The fossil record does not support the idea that all known species appeared at the same time, and there is no evidence that humans date back to the beginning of life. The fossil record is not artificially created by evolutionary biologists but is a natural record of the history of life on Earth.

Question 13

Two fossils are found in a hillside.Fossil A was found in an upper layer and fossil B was found in a lower layer.Which of the following statements is true?

Accepted Answer

Fossil B was found in a lower layer, which means it is older than fossil A found in an upper layer. Therefore, it is likely that B is the oldest of these fossils. The order of the layers in which the fossils were found indicates that they were deposited at different times, but it does not provide any evidence for evolution from one fossil to the other.

Question 14

Fossils found in deeper layers are ________ than fossils found in more shallow layers.

Accepted Answer

The deeper the layer, the older it is, so the fossils found in those layers would also be older.

Question 15

What is biological evolution?

Accepted Answer

Biological evolution is the change in the inherited characteristics of a group of organisms over generations. This includes changes in physical traits, behaviors, and genetic makeup. It is driven by mechanisms such as natural selection, genetic drift, and gene flow. It is supported by evidence from many fields including genetics, paleontology, biogeography, and comparative anatomy. Direct observation of the fossil record is a component of the evidence, but biological evolution encompasses much more than just this. Adaptations to common descent over time is also a component of biological evolution, but it does not fully capture the complexity and mechanisms involved in the process. The idea of the unchanging nature of life on Earth goes against the principles of biological evolution.

Question 16

One of the reasons scientists have had so much difficulty finding a cure for HIV/AIDS is that the HIV virus is quick to evolve resistance to the drugs used to treat it.What is the most likely mechanism for this type of evolution?

Accepted Answer

This mechanism is known as natural selection. The viruses that have a genetic variation that makes them less susceptible to drugs may survive treatment and pass those traits to their offspring. Eventually, the virus population may become resistant to the drug.

Question 17

Evolution is

Accepted Answer

Evolution is strongly supported by scientific evidence, including the fossil record, comparative anatomy, genetics, and observations of natural selection in action. The overwhelming consensus among biologists is that evolution is a fundamental scientific concept that has been extensively studied and supported by evidence over the past century.

Question 18

Equus (horses)have a single toe on their hoof,while Hyracotherium (the ancestor to horses)had four toes.Which of the following evidence would support this conclusion?

Accepted Answer

A transition fossil with three toes would provide evidence that the ancestor to horses had multiple toes, while the current horse (Equus) only has one toe. Option A is not sufficient evidence as it only shows one toe, but does not necessarily show the transition from multiple toes to one toe. Option B does not align with the current understanding of horse evolution. Option D shows that some members of the ancestor species already had one toe, but it doesn't show the transition from multiple toes to a single toe.

Question 19

Both humans and whales evolved from a common ancestor.Although our forelimbs are quite different,they are made of the same bones.This is an example of a(n)

Accepted Answer

The fact that humans and whales have forelimbs made of the same bones, but with different functions, is an example of homologous structures. This suggests that they evolved from a common ancestor that had similar forelimbs, which were then modified over time in different ways. This is not an example of artificial selection, transition fossils, or vestigial structures.

Question 20

Which of the following statements regarding the evolutionary history of an organism is FALSE?

Accepted Answer

Predictions of evolutionary relatedness based on DNA usually agree with those based on anatomical evidence, not contradict them. This is because DNA provides a more accurate measure of genetic similarities between organisms than morphological similarities.

Quiz 10: Evidence for Evolution