Bio 1 Ch13

Which of the following statements about the amoeba population described at the end of the tutorial is true? A.It is more vulnerable to extinction due to lack of genetic variation. B.It is healthier than the starting population. C.It is less vulnerable to extinction because it survived the catastrophe.

A. It is more vulnerable to extinction due to lack of genetic variation

The evolution of populations due to chance is A.genetic drift. B.natural selection. C.gene flow.genetic variation. D.has more effect in large populations than in small populations.

A.genetic drift

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? A.Gene flow causes the frequency of the green allele to increase. B.Gene flow causes the frequency of the brown allele to increase. C.Natural selection causes the frequency of the brown allele to increase. D.Natural selection causes the frequency of the green allele to increase. E.This is an example of genetic drift.

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

Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions? A.Directional selection B.Stabilizing selection C.Disruptive selection

B.Stabilizing selection

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles, A.the frequency of the brown allele will increase. B.the frequency of the green allele will increase. C.this causes the population to evolve due to gene flow. D.the frequencies of the brown and green alleles will not change. E.this causes the population to evolve due to genetic drift.

B.the frequency of the green allele will increase

Although millions of prairie chickens once roamed the Midwest, their numbers dwindled to only 50 individuals in the 1990s. These few individuals have since produced a larger population. The genetic variation among the current population is quite low.

Bottleneck effect

In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat, which type of selection would act on shell color in these snails? A.Directional selection B.Stabilizing selection C.Disruptive selection

C.Disruptive selection

In a population with brown and green alleles for color, genetic drift A.occurs when individuals move into or out of a population, changing the allele frequencies in the population. B.has more effect on the evolution of a large population. C.always increases the frequency of brown alleles in the population. D.has more effect on the evolution of a small population. E.causes populations to become better adapted to their environments.

D.has more effect on the evolution of a small population

Which of the following events could NOT be caused by a population bottleneck? A.Loss of alleles B.Reduction in genetic variability C.Changes in allele frequency D.Increased population size

D.increased population size

--------- -------- favors phenotypes at one end of a range and is common in periods of environmental change.

Directional selection

-------- -------- favors phenotypes at both ends of a range over intermediate phenotypes. This type of selection may occur when the habitat is varied.

Disruptive selection

This unequal reproduction in a population leads to the gradual accumulation of --------- to the environment.

adaptations

A sudden volcanic eruption kills many members of a population of elk. By chance, the individuals that remain do not have the same mix of genes as the original population.

bottleneck effect

The ------- of life arises from the adaptation of species to different habitats over long spans of time.

diversity

Insecticide resistance among mosquitoes is spreading around the world after mutations that originate in one population are spread to other populations through matings.

gene flow

New individuals move into a population.

gene flow

Two key observations underlying natural selection are that members of a population vary in their ------- ----- and that all species can produce more offspring than the environment can support.

inherited traits

In a type of sexual selection often called ---- ------, individuals of one sex (usually females) are choosy in selecting their mates. This choice is often based on the showy appearance or behavior of the male.

mate choice

The phrase Darwin used to describe his broad theory of evolution is ''descent with --------.''

modification

A birds beak is well-suited for cracking seeds.

natural selection

A prominent tail helps the peacock attract a mate.

natural selection

Darwin proposed a mechanism for how evolution occurs, which he called ------- -------.

natural selection

camouflage enables this insect to evade predators

natural selection

Darwin inferred that those organisms with traits best suited to the environment tend to leave more -------- than other members of a population.

offspring

As habitats change, population of northern pine trees that were once separated can now exchange pollen. This exchange of genes between population is allowing the previously isolate gene pools to mix

Gene flow

By chance, some wildflowers in this population reproduce, while others do not.

Genetic drift

-------- ------- favors intermediate phenotypes, selecting against phenotypes at both ends of a range and reducing variation.

Stabilizing selection

In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in -------- -------, differences between the sexes in size, appearance, and behavior.

sexual dimorphism

Researchers discovered that female gray tree frogs prefer to mate with males who sound the longest mating calls.

sexual selection

All of life is related through common ancestry, accounting for the ----- of life.

unity

Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection? A.Green beetles migrate out of the population. B.Green beetles and brown beetles always leave the same number of offspring. C.Green beetles migrate out of the population, and brown beetles migrate into the population. D.A storm kills more green beetles than brown beetles by chance. E.Green beetles leave more offspring than brown beetles because they are better at finding food.

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

True or False. In the example described in the tutorial, the red amoebas survived the catastrophic event, and all future generations of amoebas were red because the red amoebas had a higher reproductive rate than the blue ones.

False

Tristan da Cunha is a remote island in the Atlantic Ocean. in 1814, 15 people formed a colony there, one of whom carried a rare gene for blindness. The frequency of this gene is now 10 times higher on the island than on the mainland which the settlers arrived.

Founder effect