Bio 109 Midterm 1

In any population, the odds of surviving are due to chance. True False

False

True or false: Natural selection occurs so an organism can become perfectly adapted to its environment. True False

False

With proper care, all the offspring in a generation will survive. True False

False

Why can evolution in mosquitoes be more easily observed than evolution in a population of squirrels? Mosquitoes have a shorter generation time. Mosquitoes have a higher mutation rate. Mosquitoes lay eggs rather than bear live young. Mosquitoes feed only on blood.

Mosquitoes have a shorter generation time.

Is it possible to prevent bacteria from becoming resistant to antibiotics? No: Bacteria need to become resistant to anything that will kill them. Yes: If we give antibiotics properly, resistance will go away and not evolve again. Yes: If we stop using antibiotics, the trait will disappear. No: However, by using antibiotics properly, we can slow the rate at which resistance appears.

No: However, by using antibiotics properly, we can slow the rate at which resistance appears.

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? Disruptive selection Stabilizing selection Directional selection

Stabilizing selection

You notice that some squirrels in your neighborhood have a much darker coat color than most of the other squirrels. Is this darker color an adaptation? The trait is only an adaptation if it gives the squirrels an advantage in their habitat. Yes, all variations are adaptations. No, adaptations are traits developed when they're needed to help an organism survive. You can't know unless you can know the coat color of the dark squirrel's parents.

The trait is only an adaptation if it gives the squirrels an advantage in their habitat.

Evolution can be best defined as ________. the production of new species change in allele frequency in a population not involving humans always taking a very long time to occur

change in allele frequency in a population

A trait that confers ________ in one environment might make an organism less able to survive and reproduce in another environment. fitness alleles selection adaptation

fitness

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

genetic drift.

Individuals with variations that make them best suited to their environment will, on average, be more likely to ________. evolve change over time survive and reproduce be larger

survive and reproduce

Which of the following contributes the LEAST to the problem of antibiotic resistance? using high doses of antibiotics in animal feed, so that we are not exposed to the bacteria stopping taking the antibiotics as soon as you feel better, thereby decreasing the exposure of the bacteria to the antibiotics taking antibiotics for all infections, including viral infections taking the entire course of antibiotics as prescribed by the doctor

taking the entire course of antibiotics as prescribed by the doctor

In natural selection, what changes in a population over time? the reproductive capacity of individuals the phenotype of individuals the number of favorable adaptations among individuals the frequency of an allele for a particular gene in a population

the frequency of an allele for a particular gene in a population

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

the frequency of the green allele will increase.

What do alleles give rise to in a population? variation reproductive success competitive advantage genetic defects

variation

In which situation can just a few genes dramatically change an organism's entire appearance? when the genes each control the expression of many other genes when the genes are each thousands of nucleotides long all situations, because in general, individual genes have big effects on an organism's appearance when an organism has only a few genes

when the genes each control the expression of many other genes

Which of the following mechanisms can drive evolution? Genetic drift Natural selection Mutations All of the above

All of the above

Which of the following is not part of the theory of natural selection? Some variation can be passed on to offspring. All species are descended from a common ancestor. Populations produce more offspring than the environment can support. Individuals in a population vary.

All species are descended from a common ancestor.

Which of the following best defines microevolution? Changes in genes between populations Changes in genes that do not change the gene pool over time Changes in genes within a population over time Changes across species but not in genes

Changes in genes within a population over time

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? Stabilizing selection Directional selection Disruptive selection

Disruptive selection

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 green allele to increase. Natural selection causes the frequency of the green allele to increase. This is an example of genetic drift. Natural selection causes the frequency of the brown allele to increase. Gene flow causes the frequency of the brown allele to increase.

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

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

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

As proposed by Darwin, what sorts of traits are favored by natural selection? Any traits that are produced by mutation and can be inherited. Traits that reduce the number of offspring an individual produces, thus helping to reduce the struggle for existence in the next generation. Traits that reduce the mutation rate and cut down on unnecessary variation within populations. Heritable traits that help individuals survive and reproduce more successfully than others in the same population

Heritable traits that help individuals survive and reproduce more successfully than others in the same population.

What defines a population in evolution? Multiple species interacting together Members of the same group that share a common ancestor Interbreeding members of the same species Members of a single species

Interbreeding members of the same species

Why is the phrase "survival of the fittest" somewhat misleading? It implies that the best possible organism will evolve. It implies that humans are the proper end result of evolution. It implies that there's random generation of variation. It implies that organisms will always grow bigger and more complex.

It implies that the best possible organism will evolve.

A particular antibiotic kills 99% of a bacterial population. What will be the result of the continued application of this antibiotic? Every time the antibiotic is given, it will kill 99% of the bacterial population. Over time, the antibiotic will become less effective at killing the bacteria. Eventually, all of the bacterial population will be wiped out. Over time, the antibiotic will cause mutations in the bacteria.

Over time, the antibiotic will become less effective at killing the bacteria.

Which two observations led Darwin to conclude that there is competition for survival? Fossils and mutations Gene and allele differences in organisms Natural selection and descent with modification Overproduction and limited resources

Overproduction and limited resources

What is the concern about using antibacterial and antimicrobial soaps? The use of any chemical that kills bacteria can eventually lead to resistance to that chemical in the population of bacteria. Antibacterial and antimicrobial products are far more toxic to humans than are antibiotics. Doctors are concerned that people will stop using antibiotics, and start using more antibacterial and antimicrobial products instead. Antibacterial and antimicrobial products are far more toxic to bacteria than are antibiotics.

The use of any chemical that kills bacteria can eventually lead to resistance to that chemical in the population of bacteria.

Which of the following conditions are required for evolution to occur? Select all that apply. There must be equal reproductive success among individuals in a population. Most offspring must survive. Resources must increase at the same rate that the population grows. Traits must be heritable. Individuals within a population must vary in their ability to compete for resources. Resources in the environment must be limited.

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

True or false: Natural selection is only one of several possible causes of evolution. True False

True

You can observe that at least some traits pass from parent to offspring. True False

True

You can observe that members of a biological population differ from one another. True False

True

Your friend was diagnosed with strep throat 2 months ago. She was treated with antibiotics for 10 days, but 2 weeks after treatment, the symptoms returned. She was given a different antibiotic and her symptoms improved again, initially, but then got worse. What is happening? Your friend has taken antibiotics so long that she has become tolerant to them, making them ineffective. Your friend probably doesn't have a bacterial infection. There must be some other reason for her symptoms. Exposure to antibiotics has caused each individual bacterial cell to evolve resistance to the antibiotics. Your friend was originally infected with some bacteria that were resistant to these two antibiotics and the bacteria multiplied.

Your friend was originally infected with some bacteria that were resistant to these two antibiotics and the bacteria multiplied.

Which of the following is the best definition of adaptation? a variation that increases fitness in a population a trait favored by natural selection an increase in allele frequency in a population a trait that occurs at low frequency

a trait favored by natural selection

Your aunt's garden has a mix of native plants. Of the yellow coneflowers growing this year, some have shallow roots that extend only 4 or 5 inches below the surface. Others have roots that extend 10 to 12 inches below the surface. Severe drought, that is, lack of precipitation, afflicts your aunt's region for 6 months. Now, based on common knowledge and your understanding of natural selection, which kind of yellow coneflower will there be more of next year in your aunt's garden? deep-rooted plants new, even-deeper-rooted plants new, intermediate-rooted plants shallow-rooted plants

deep-rooted plants

Over time, bacteria have become increasingly resistant to antibiotics. Which of the following best explains this in terms of natural selection? Antibiotics caused bacteria to reproduce more quickly than normal Antibiotics caused mutations in the bacteria that were exposed to the largest doses of antibiotics Bacteria that happen to have natural resistance to antibiotics survived and reproduced Some bacteria began to tolerate the antibiotics, and passed this ability to their offspring

Bacteria that happen to have natural resistance to antibiotics survived and reproduced

What is the original source of variation that natural selection can act upon? Gene flow Mutation Genetic drift All of the above

Mutation

Natural selection is best described as _____. a creative force that efficiently develops the best and simplest solutions for all problems in nature a forward-looking process that anticipates future problems and designs the necessary tools to solve them through mutation a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations a completely random and unpredictable process of change, or evolution

a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations

Which example shows nonevolutionary change in a population? an increase in mosquitoes that are resistant to insecticide plants in a dry climate that have faster-growing roots than plants found there 20 years ago after decreases in airborne soot, a change in the most common color of moths an increase in the number of people diagnosed with colon cancer

an increase in the number of people diagnosed with colon cancer

What type of selection would include the evolution of a long neck in giraffes? directional selection diversifying selection disruptive selection stabilizing selection

directional selection

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

has more effect on the evolution of a small population.

Natural selection acts on ________, and ________ evolve. populations; individuals populations; populations individuals; populations individuals; individuals

individuals; populations