Mastering Biology Pollinators II: Chapter 13

If the frequency of one allele in a population is 0.7 in a population with two alleles at a particular locus, what is the frequency of the alternate allele?

0.30

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

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

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

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

Which result might be a consequence of stabilizing selection?

Infants born with weights between 3 and 4 kg have a higher survival than infants much lighter or heavier at birth.

Which of the following are true of the "death" of the icefish globin gene?

Mutations destroyed the function of the icefish globin gene.

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.

Which statement is true of the Notothenioids?

Notothenioids can live in very cold, nutrient-rich waters where other fish species cannot.

Which situation is an example of sexual selection?

Peahens choose to mate with peacocks that have the brightest tails.

Compare sickle cell disease and malaria.

Sickle cell disease and malaria are both potentially lethal diseases

Which is a characteristic of a population at Hardy-Weinberg equilibrium?

The population is not evolving.

Which phenomenon (or lack of) will prevent significant genetic drift?

The population size is large.

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.

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

There is no selection for dark bellies by visual predators

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 organism's DNA

A strong selective pressure (like very cold water) can __________.

cause a reproductive advantage for an individual with an advantageous mutation

The total collection of alleles in a population at any one time makes up that population's ________.

gene pool

A change in the gene pool due to chance results in ________.

genetic drift

Chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. In some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. If these resistant individuals continue to survive and prosper, new resistant populations might emerge. This would be an example of ________.

natural selection

The presence of freckles is due to a dominant allele. Four percent of the individuals in a particular population lack freckles. Use the Hardy-Weinberg formula to calculate the percentage of individuals in this population who are homozygous dominant for freckles.

64%

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.

In the Hardy-Weinberg formula, what does 2pq represent?

frequency of heterozygotes

In the Hardy-Weinberg formula, what does p2 represent?

frequency of the homozygotes for one allele

Imagine that a new population of humans is established on a previously uninhabited planet from ten randomly selected people in your biology class. Over thousands of years, the descendants of those ten people reproduce and prosper, but they do not reflect well the diversity of humans on Earth. This reduction in genetic diversity in the establishment of the population is an example of __________.

the founder effect The type of genetic drift resulting from the establishment of a small, new population whose gene pool differs from that of the parent population is called the founder effect.

How did the icefish antifreeze gene arise?

An existing gene was accidentally duplicated. It then acquired mutations, which caused it to have a different function.

Which of these characteristics affects the diffusion oxygen into the icefish's blood?

Icefish have transparent, scale-less skin.

Icefish live in very cold waters (-1.8 degrees Celsius) where temperatures are below blood's freezing point. Which statements are true about icefish adaptations for cold water?

Icefish lack red blood cells, which reduces the viscosity (thickness) of blood, allowing it to flow more freely at cold temperatures. Icefish have antifreeze proteins, which prevent blood from freezing.

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.

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.

According to current evolutionary theory, which of the following is true?

Populations are the units of evolution.

Compare the "birth" and "death" of icefish genes.

The "birth" of the antifreeze gene and the "death" of the globin gene are both caused by mutation.

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.

After surviving a bottleneck, a population recovers to the point where it consists of as many individuals as it did prior to the bottleneck. Which statement is most likely to apply to this population?

The post-bottleneck population exhibits less genetic variation than the pre-bottleneck population.

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?

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

The relationship of the genome to an organism is similar to that of the __________ to a population.

gene pool

The founder effect differs from a population bottleneck in that the founder effect ________.

involves the isolation of a small colony of individuals from a larger population

Organisms from the same phylum all belong to the same __________.

kingdom From the most broad to the least broad, the levels of taxonomic hierarchy are domain, kingdom, phylum, class, order, family, genus, and species.