Question 1

Four mechanisms can change the composition of a population's gene pool,but only ________ does so by creating new alleles.

Accepted Answer

Genetic drift, natural selection and gene flow can change the frequency of existing alleles in a population's gene pool, but only mutation can create new alleles. Therefore, choice B is the correct answer.

Question 2

Biological evolution can be defined as

Accepted Answer

Biological evolution is defined as the change in allele frequencies in a population's gene pool over time. This can lead to adaptations and the appearance of new traits and species, ultimately resulting in common descent among diverse life forms. Observation plays a critical role in understanding evolution, but it is not the definition of the process. Evolution does not imply an unchanging nature of life on Earth, as it is precisely the opposite: a dynamic and ongoing phenomenon that has produced immense biodiversity.

Question 3

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 a change in the allele frequencies of the surviving population. This is an example of genetic drift, in which chance events can cause random fluctuations in allele frequencies within a population. The hurricane does not affect the mutation rate of the population, the sex ratio, or the habitat of the population.

Question 4

Jean-Baptiste Lamarck proposed that changes in the characteristics of a population are a result of traits acquired during an organism's lifetime being inherited by that organism's offspring.What is wrong with this proposal?

Accepted Answer

Lamarck's proposal is based on the idea that traits acquired during an organism's lifetime can be passed down to its offspring, but this is not supported by genetics. Only changes in the DNA sequence of an organism can be inherited, and traits that are acquired throughout life generally do not alter DNA.

Question 5

Before the industrial revolution,scholars believed that Earth was only 6,000 years old.What evidence first suggested that this belief might NOT be correct?

Accepted Answer

Geological studies indicated that Earth's surface features were shaped by slow processes over long periods, suggesting an older Earth than previously believed.

Question 6

In genetic drift,the events that affect the survival and reproduction of individuals in a population occur

Accepted Answer

Genetic drift refers to the random fluctuations in the frequency of alleles in a population. The events that affect the survival and reproduction of individuals in a population under genetic drift occur primarily by chance. There is no predicting these events or a particular pattern to them.

Question 7

Peppered moths in England evolved into a dark-colored form when soot darkened the bark of the trees they lived on and exposed the light-colored form to predation.However,air pollution control eventually restored the moths' habitat to its original condition.What would probably have happened to the peppered moth population if the light-colored alleles had been entirely lost from its gene pool during the period when dark-colored moths were selectively favored?

Accepted Answer

If the light-colored alleles were entirely lost from the gene pool and air pollution controls later restored the environment, the population would not have the genetic variation necessary to adapt to the environment. Without the adaptive trait, the population would likely face severe predation pressure and would become extremely small or possibly go extinct. Mutations may occur, but it would take a long time for the light-colored allele to be reestablished in the gene pool. Behavioral and dietary changes are also unlikely to save the population in this scenario.

Question 8

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

Accepted Answer

This example demonstrates natural selection because the darker moths have a higher survival rate in areas with soot-covered tree trunks, allowing them to pass on their advantageous traits to their offspring.

Question 9

The main conclusion Darwin reached after his return from the expedition aboard the HMS Beagle was that

Accepted Answer

The answer of The main conclusion Darwin reached after his...

Question 10

Which of the following things is an example of gene flow?

Accepted Answer

Pollen grains can carry genetic information from one population to another, allowing gene flow between these populations. This can occur even if the populations are geographically separated by long distances. The other options listed do not involve the movement of genetic material between populations.

Question 11

Many weeds have become resistant to the herbicides that were once used to control them.Which of the following statements best explains this observation?

Accepted Answer

The observation that weeds have become resistant to herbicides can be explained by the process of natural selection acting on the genetic variability in weeds' genomes, favoring plants that have herbicide resistance traits and allowing them to reproduce more successfully. This selection pressure over time can lead to the evolution of populations of weeds that are resistant to herbicides. The other options provided, including A) the evolution of different species or B) the evolution of herbicides, do not accurately explain the observed pattern of herbicide resistance in weeds. Continental drift, as described in C), is also not a relevant factor in this scenario.

Question 12

Which of the following statements best describes what happens in gene flow?

Accepted Answer

Gene flow occurs when individuals migrate from one population to another and contribute their alleles to the gene pool of the recipient population. This can increase genetic variation and potentially alter the frequencies of alleles in the population.

Question 13

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

Accepted Answer

Genetic differences arise in a population primarily through mutation, which is a change in the DNA sequence of an organism's genome. This mutation can then be passed on to future generations, leading to heritable genetic differences within the population. While behavior can affect an organism's fitness and likelihood of passing on genes, it does not directly lead to genetic variation. Natural selection and common descent are mechanisms that act on existing genetic variation but do not generate it.

Question 14

Genetic variation is based on

Accepted Answer

Genetic variation is based on the differences in DNA sequences between the individuals in a population. These differences can arise through mutation, recombination, and immigration. The other options listed are not accurate descriptions of the basis of genetic variation.

Question 15

In populations that have a high degree of genetic diversity,the fundamental cause of evolutionary change is

Accepted Answer

Populations with high genetic diversity have a greater potential for variation, allowing natural selection to act upon them and drive evolutionary change. While continental drift and long-term climatic changes may play a role in the environment of an organism, they do not directly cause genetic diversity or change. Mutation, on the other hand, is a source of genetic diversity but is not necessarily the fundamental cause of evolution, as it is the interaction between genetic variation and the environment (through natural selection) that leads to evolutionary change.

Question 16

Species like the African cheetah,northern elephant seal,and Florida panther have all experienced a genetic bottleneck; what is the primary outcome of this experience?

Accepted Answer

The primary outcome of genetic bottleneck is that the genetic diversity of a population is greatly reduced. This occurs when a population undergoes a dramatic reduction in size, often due to natural disasters or human activities, leading to a limited number of individuals contributing to the gene pool of future generations. As a result, certain genetic variations and alleles may be lost, making the population less resilient to environmental changes and increasing the risk of inbreeding depression.

Question 17

Natural selection tends to

Accepted Answer

The answer of Natural selection tends to
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Question 18

Which of the following statements about natural selection is true?

Accepted Answer

Natural selection is the principal cause of evolutionary change, as it acts on the traits that influence an organism's survival and reproductive success. It can lead to the adaptation of species to their environment over time. Option A is incorrect because althoughnatural selection can contribute to extinction in certain situations, it is not the principal cause. Option C is false because natural selection can occur in any type of cell that contains genetic material, not just gametes. Option D is also incorrect since genetic drift is a different mechanism of evolutionary change that can occur independently of natural selection.

Question 19

One frequently observed example of evolution is

Accepted Answer

Bacteria developing increased resistance to antibiotics is a clear example of evolution in action. As antibiotics are used to kill bacteria, those with genetic mutations that allow them to survive the antibiotic treatment will be more likely to survive and reproduce, passing on their resistant traits to their offspring. Over time, this can lead to the evolution of entirely new bacterial strains that are resistant to multiple antibiotics.

Question 20

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

Accepted Answer

The correct mechanism is natural selection, where certain versions of the virus that are slower to die when exposed to a drug survive and pass on their resistant genes to their offspring.

Quiz 14: How Evolution Works