Question 1

A hurricane could cause genetic drift by

Accepted Answer

A hurricane can randomly kill more individuals of one genotype than another in a population, leading to changes in the frequency of alleles in the population, which is genetic drift. The other options may be possible outcomes of a hurricane, but they do not directly cause genetic drift.

Question 2

Natural selection

Accepted Answer

Natural selection is the principal cause of evolutionary change as it is the process by which traits that are advantageous for survival and reproduction become more common in a population over time. Option A is incorrect as extinction can also be caused by factors such as habitat destruction and climate change. Option C is incorrect as natural selection occurs in all cells that undergo replication, not just gametes. Option D is incorrect as genetic drift can occur independently of natural selection.

Question 3

Evolution can be described as

Accepted Answer

Evolution is the change in the genetic makeup of a population over time. This occurs through various mechanisms such as natural selection, genetic drift, and mutations. It is not predetermined or sudden, but rather gradual and ongoing. Isolation due to geologic forces may lead to speciation, but it is not evolution itself.

Question 4

Evolutionary changes occur when _______ acts upon populations containing individuals with genetic differences.

Accepted Answer

Natural selection acts upon populations containing individuals with genetic differences, favoring those individuals that are better suited to their environment and increasing their likelihood of passing on their beneficial traits to the next generation. Continental drift and weather do not directly result in evolutionary changes, although they may indirectly influence them. Mutation is a source of genetic variation, but evolutionary changes only occur when natural selection acts upon the resulting genetic differences.

Question 5

During a windstorm, a tree falls on the population of wildflowers shown in the figure below. Most of the flowers die (as indicated by the tombstones in the second row). The survivors go on to reproduce. 
What will the next generation of this wildflower population look like?

Accepted Answer

Since the gray flower color is dominant, the survivors must have been heterozygous (Gg) for flower color. The offspring of these survivors will have a 3:1 ratio of gray (GG or Gg) to white (gg) flowers, resulting in three quarters of the flowers being gray and one quarter being white.

Question 6

Convergent evolution produces

Accepted Answer

Convergent evolution is the independent evolution of similar features in species of different lineages. These features are called analogous characteristics because they have similar functions but different evolutionary origins. Therefore, option D is the correct answer. Genetic drift is a random fluctuation in allele frequencies that occurs in small populations and does not relate to convergent evolution. Lines of common descent and homologous characteristics are related to divergent evolution and do not apply to convergent evolution.

Question 7

The main conclusion Darwin reached after his return from the Galápagos Islands was that

Accepted Answer

Darwin's observations in the Galápagos, particularly the variations in finches and tortoises on different islands, led him to develop his theory of evolution by natural selection. He concluded that species of animals change over time, instead of remaining static, and it was this idea that revolutionized the field of biology.

Question 8

Convergent evolution occurs when natural selection causes distantly related organisms to

Accepted Answer

Convergent evolution occurs when distantly related organisms develop similar structures or traits in response to similar environmental pressures. This is often seen in unrelated species living in similar habitats, such as the wings of bats and birds for flight.

Question 9

A population of mice lives along a river. Some mice cross the river to establish a new population. Eventually, due to genetic changes, these two groups of mice can no longer interbreed. This is an example of

Accepted Answer

The separation and subsequent genetic changes that result in the inability of two groups of organisms to interbreed is known as speciation. This is the process by which new species arise.

Question 10

Two different species may have similar features because of

Accepted Answer

Similar features in two different species are best explained by descent from a common ancestor, which is the fundamental principle of evolutionary biology. Genetic drift can cause random changes in the genetic makeup of small populations, but it is unlikely to produce similar features in distantly related species. The fossil record and artificial selection can explain certain aspects of evolution, but they do not account for the similarity of species that share a common ancestor.

Question 11

Biological evolution can be defined as

Accepted Answer

Biological evolution refers to the changes that happen in a population's genetic characteristics over time. These changes occur as a result of natural selection, genetic drift, and other mechanisms, and they can lead to the development of new species over time. Options A, B, and C don't fit the definition of biological evolution.

Question 12

Which of the following is not likely to contribute to evolution within a population?

Accepted Answer

Evolution relies on changes in the genetic makeup of a population, which can happen through mutation, natural selection, and genetic drift. An unchanging environment would mean that there is no selective pressure for organisms to evolve and adapt to new conditions, so evolution would not occur.

Question 13

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

This example demonstrates natural selection as the darker colored moths have a better chance of survival in areas where the tree trunks are blackened with soot, allowing them to blend in better and avoid predation. Artificial selection, genetic drift, and vestigial coloration do not apply to this scenario.

Question 14

Natural selection tends to

Accepted Answer

Natural selection favors traits that increase an organism's chances of survival and reproduction, so over time, these traits become more common in a population. Therefore, the frequency of characteristics that enhance survival and reproduction tends to increase. Option B is incorrect because the number of individuals in a population is not necessarily directly related to natural selection. Option C is incorrect because genetic drift is a random process that occurs independent of natural selection. Option D is incorrect because natural selection actually increases the likelihood of adaptation, as it favors traits that help organisms survive and reproduce in specific environments.

Question 15

For a population to evolve, there must be genetic differences between organisms in that population. These differences arise by

Accepted Answer

Genetic differences arise in a population through mutations, which are random changes in an organism's DNA.

Question 16

Genetic drift refers to ______ events that affect the survival and reproduction of individuals in a population.

Accepted Answer

Genetic drift refers to random events that affect the survival and reproduction of individuals in a population, such as natural disasters or chance variations in mating patterns. It is unpredictable and can lead to significant changes in the gene pool of a population over time.

Question 17

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

HIV evolves resistance through natural selection, where variants that survive drug treatment due to advantageous mutations pass those traits to their offspring.

Question 18

Certain weeds have become resistant to the pesticides that were used to kill them. Which of the following choices is the best explanation for this phenomenon?

Accepted Answer

Natural selection acted on the genetic variability present in the weeds' genomes. This means that the weeds that had genetic variations that made them resistant to the pesticides survived and reproduced, passing on those resistant genes to their offspring. Over time, this led to a population of weeds that are resistant to the pesticides.

Question 19

Flounder (a type of fish) generally match the color of the sandy bottoms they inhabit. Their color allows them to hide from other organisms that might eat them. This is an example of

Accepted Answer

The flounder's coloration is an example of adaptation, as it allows them to blend in with their environment and avoid predation. Speciation refers to the process of one species splitting into multiple new species. Continental drift is a geological process related to the movement of tectonic plates. Guided mutation is not a recognized scientific concept.

Question 20

A species of cave beetle that lives in total darkness is blind but has remnants of what looks like eyes. These "eyes" are

Accepted Answer

Remnants of eyes indicate that the beetle's ancestors had functional eyes. However, because the current beetles do not use their eyes and live in total darkness, the eyes have become vestigial.

Quiz 16: How Evolution Works