Mastering Biology 7

Why do dark colored rock pocket mice on dark lava flows have white bellies?

there is no selection for dark bellies by visual predators. The color of a rock pocket mouse's belly is not visible to a predator and therefore is not under strong selection pressure.

Which of the following sets of animals are likely to be found on the Galapagos Islands?

tortoises, finches, blue-footed boobies

Natural selection is based on all of the following except

individuals adapt to their environments and, thereby, evolve.

Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship.

2 → 4 → 1 → 3

Where are the Galapagos Islands located?

600 miles west of Ecuador, near the equator

Which of these naturalists synthesized a concept of natural selection independently of Darwin?

Alfred Wallace

Which of these conditions should completely prevent the occurrence of natural selection in a population over time?

All variation between individuals is due only to environmental factors.

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Characteristics acquired during an organism's life are generally not passed on through genes.

In the lab, Nachman examined dark mice from two different populations living hundreds of miles apart. The mice looked nearly identical. Their dark color was caused by two different genes. What does this tell you?

Dark fur color evolved independently on each lava flow. Under very similar conditions, natural selection can favor very similar adaptations. There are at least two genes involved in creating dark mouse fur. Two completely different mutations in two separate genes can generate the same phenotype.

What was the prevailing notion prior to the time of Lyell and Darwin?

Earth is a few thousand years old, and populations are unchanging.

Which of the following must exist in a population before natural selection can act upon that population?

Genetic variation among individuals

When dark-colored fur gives mice a 1% competitive advantage and 1% of the population begins with dark fur, in about 1000 years, 95% of the population will have dark fur. Which of the following statements is true?

If dark-colored rock pocket mice had a competitive advantage of 0.1%, it would take longer for 95% of the population to have dark fur. A small evolutionary advantage can lead to large changes in a population. The larger the advantage, the faster the changes occur.

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that. The rock pocket mice that Dr. Nachman catches in the film have a mutation in a gene that leads to the dark fur color.

What does Dr. Carroll mean when he says, "while mutation is random, natural selection is not"?

Natural selection favors some mutations. Mutations for advantageous traits are more likely to be passed on to the next generation. Natural selection acts on traits. Natural selection can only work on variation existing in a population. Mutation creates variation randomly. Natural selection is not random; by determining which traits are passed to the next generation, it can shape populations.

Sort the following examples into the correct categories.

Scientists have directly observed evolution occurring in many instances, including the development of drug resistance in bacteria and other pathogens. The fossil record has provided evidence for extinct species and for transitional forms of organisms, such as the ancestors of present-day horses. Homologies include similarities in structure, development, and DNA sequences in different organisms. Vestigial structures are homologous structures that have a reduced function or no function at all. Examples include the pelvic bones of whales. The geographic distribution of species, such as the high concentration of marsupial mammals in Australia, can provide evidence about common ancestors. In addition, the endemic species found on many island chains yield information about evolution on those islands.

Which of Darwin's ideas had the strongest connection to Darwin having read Malthus's essay on human population growth?

Struggle for existence

Why did dark-colored rock pocket mice first appear in a population of light-colored rock pocket mice?

They have a genetic mutation that affects their fur color.

Mutations are always __________.

a change in an individual's DNA. Mutations are rare genetic changes that can be neutral, beneficial, or detrimental depending on an individual's circumstances. A dark-color fur mutation is good for a rock pocket mouse living on black lava and bad for one living in the sandy desert.

Charles Darwin was the first person to propose

a mechanism for evolution that was supported by evidence.

The Galapagos Islands were the first place on Earth to _____.

be declared a world heritage site

Tourism on the Galapagos Islands is being restricted by requiring tourists to _____.

be escorted by trained guides at all times

As a young biologist, Charles Darwin had expected the living plants of temperate South America would resemble those of temperate Europe, but he was surprised to find that they more closely resembled the plants of tropical South America. The biological explanation for this observation is most properly associated with the field of

biogeography.

Which species is threatening the natural wildlife on the Galapagos Islands?

humans

In Darwin's thinking, the more closely related two different organisms are, the

more recently they shared a common ancestor.