BIO 101 ch.7

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?

Gene flow causes the frequency of the brown allele to increase.

Habitat loss has driven the population of the Florida panther (Puma concolor cougar) to extremely low numbers. Which mechanism of microevolution is likely at play in this species?

Genetic drift: the bottleneck effect

Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?

Green beetles leave more offspring than brown beetles because they are better at finding food.

Consider a population of snowshoe hares in Montana. Their fur color changes in response to changes in day length. During the long summer days, they have brown fur, but as the days shorten in the fall, their fur turns white in preparation for winter. Then as the days get longer in the spring, their fur turns brown again. Their fur coloration acts as camouflage from predators. As climate change brings warmer fall temperatures to Montana, colder temperatures with snowfall are coming later in the year, and there may be less snowfall overall. As a result, the hares' fur color may be mismatched to the color of their surroundings, making them more visible to predators.

Hares with a mutation that causes them to change color in response to temperature rather than day length

How did Dr. Allison test his hypothesis that sickle cell disease was connected to malaria?

He evaluated blood samples for malaria parasites and the presence of sickle cells. He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected.

How might global warming result in most grizzly bears having fur that is less dense in the future?

In any population of bears, some individuals have thick fur, some have thin fur, and some are in between. As temperatures increase with the passage of time, the survival of bears with thin fur will increase, and the number of bears in the population with thick fur will decrease.

Why is natural selection considered to be the most important mechanism of microevolution?

Natural selection is the only mechanism that consistently leads to adaptive changes in populations.

Which of the following conditions are required for evolution to occur?

Resources in the environment must be limited. Traits must be heritable. Individuals within a population must vary in their ability to compete for resources.

Compare sickle cell disease and malaria.

Sickle cell disease and malaria are both potentially lethal diseases.

Predict what will happen to the frequency of the sickle cell allele in areas where malaria has been eradicated.

The sickle cell allele will decrease in frequency.

Female fireflies choose mates based on the specific flash pattern displayed by males flying nearby. This is an example of

behavioral isolation

Consider a population of birds living on an island. Suppose several individuals of the same species from a different population migrate to the island. Due to the arrivial of the new birds, the allele frequencies in the original population change.

gene flow

The evolution of populations due to chance is

genetic drift.

In a population with brown and green alleles for color, genetic drift

has more effect on the evolution of a small population.

Cauliflower, broccoli, Brussels sprouts, cabbage, and kohlrabi are all the same species of plant. What is responsible for the differences in these vegetables?

Artificial selection

How does Dr. Allison's work provide an example of natural selection in humans?

In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease. In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles.

In some populations, 1 in 500 people have sickle cell disease. What reason does the film give for why a potentially deadly, inherited disease is found at such high frequencies?

Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population.

If a person has two normal copies of the hemoglobin allele, which statements are true?

The person is homozygous at the hemoglobin locus. The person is susceptible to malaria.

In the Grand Canyon, fossils in rock layers at the bottom of the canyon are __________ than those in layers closer to the top.

older

Darwinian fitness is measured only in terms of

the contribution that an individual makes to the gene pool of the next generation in comparison to the contributions from other individuals

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,

the frequency of the green allele will increase.

In 1949, Dr. Tony Allison observed a high frequency of Kenyans carrying the sickle cell allele in coastal areas and near Lake Victoria, but a lower frequency in the highlands. What did he hypothesize?

He hypothesized that there was a connection between malaria and sickle cell disease.