Mastering Biology 2 - Natural Selection

Antibiotics are used to kill all of the infectious bacteria in a person.

*video link: http://mediaplayer.pearsoncmg.com/assets/2WQYSSWRjbE_0z0qnqefyXgJ9m_iOt37 * Which of the following correctly describes what the video referred to as a "microbial cure"? - Antibiotics are used to treat all infections, whether they are bacterial or viral, in order to bring about a full cure. - Antibiotics are used only until the patient feels better, therefore reducing the exposure to the antibiotics. - Antibiotics are used to kill all of the infectious bacteria in a person. - Antibiotics are used every time a patient has disease symptoms, in order to prevent an infection from occurring.

A few bacteria experienced random mutations in their DNA, which allowed some of them to grow even though antibiotics were present.

n the projected video showing the growth of bacteria, why did the bacteria grow up to the edge of the area with antibiotics, pause, then continue to grow across the area with antibiotics? - Researchers added antibiotic resistant bacteria to the culture, so that the bacteria would continue to grow across the area with antibiotics. - The antibiotics caused mutations in the DNA of the bacteria, making them resistant to the antibiotics. - A few bacteria experienced random mutations in their DNA, which allowed some of them to grow even though antibiotics were present. - The bacteria mutated as a survival response to the presence of antibiotics, enabling the bacteria to become resistant to the antibiotics.

the ability of an individual to produce offspring that survive and reproduce, relative to other individuals in the population.

Biological fitness is best defined as

the ability of an individual to produce surviving offspring

In biology, fitness is defined as _____.

Triazine-resistant weeds were more likely to survive and reproduce.

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened? - Triazine-resistant weeds were more likely to survive and reproduce. - Natural selection caused the pigweed to mutate, creating a new triazine-resistant species. - Triazine-resistant pigweed has less efficient photosynthesis metabolism. - The herbicide company lost its triazine formula and started selling poor-quality triazine.

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

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

evolution of yet larger, deeper beaks over time

After the drought of 1977, researchers on the island of Daphne Major hypothesized that medium ground finches that had large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is correct, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where T. cistoides is the most abundant food for the next 1000 years? Assume that (1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fruits and would eat other seeds when offered a choice; and (2) food availability is the primary limit on finch fitness on this new island. - no change in beak size and shape - random fluctuations in beak size and shape - evolution of yet larger, deeper beaks over time - evolution of smaller, pointier beaks over time

All of them.

Chris has drawn a model of grass plants to represent which of Darwin's postulates? Select all that apply. - Variation exists among individuals in a population. - Some variation is heritable. - Survival and reproductive success is variable. - Survival and reproductive success is nonrandom.

determine if hair length is heritable

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should _____.

None of the insect pests would have genetic variations that resulted in DDT resistance.

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Instead, DDT is largely useless against many insects. Which of these would have prevented this evolution of DDT resistance in insect pests? - The frequency of DDT application should have been higher. - Larger doses of DDT should have been applied from the air, into water, and within the soil. - DDT application should have been continual. - All habitats should have received applications of DDT at about the same time. - None of the insect pests would have genetic variations that resulted in DDT resistance.

No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host. A cell's drug susceptibility or resistance does not affect its ability to infect another host, although a cell's drug resistance would increase that cell's chances to spread in an environment containing antibiotics due to increased survival.

Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype?

Beak depth will differ between pre- and post-drought populations Beak characteristics should change if natural selection has occurred, but the direction of change (i.e., larger or smaller) has not been predicted.

For the experiment shown in the figure, which is the most accurate statement of the prediction made by the experimental hypothesis? - Beak depth will be the same in pre- and post-drought populations. - Beak depth will be larger in post-drought versus pre-drought populations. - Beak depth will differ between pre- and post-drought populations. - Beak depth will be smaller in pre-drought versus post-drought populations.

Darwin's four postulates can be summarized as follows: Individuals in a population vary in the traits they possess. Some trait differences are heritable. Survival and reproductive success are variable among individuals in a population. Individuals with certain traits are more likely to survive and reproduce.

Identify the four postulates of natural selection. - Individuals in a population all possess the same traits. - All individuals in a population have equal reproductive success. - Survival and reproductive success are variable among individuals in a population. - Individuals with certain traits are more likely to survive and reproduce. - Individuals in a population vary in the traits they possess. - Some trait differences are heritable.

These bacteria would be outcompeted and replaced by bacteria that have lost these genes.

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics? - These bacteria would be outcompeted and replaced by bacteria that have lost these genes. - These bacteria would try to make the cost worthwhile by locating and migrating to microenvironments where traces of antibiotics are present. - The number of genes conveying antibiotic resistance would increase in these bacteria. - These genes would be maintained in case the antibiotics appear.

has more offspring that survive and reproduce themselves.

If you say that a ground squirrel has greater evolutionary fitness than another ground squirrel in the same population, you mean that the animal

The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers. If all these conditions are true, then the corn borer might evolve resistance to the toxic protein.

In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer? - The corn borers must experience no success in their ability to survive or reproduce. - The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers. - The corn borer must lack variation in resistance to the toxic protein. - The corn borers must experience unlimited success in their ability to survive or reproduce.

encouraging big pharmaceutical companies to start investing again in new drug research and development

In the video, what does the UK's Chief Medical Officer suggest for promoting the development of new antibiotics? - encouraging big pharmaceutical companies to start investing again in new drug research and development - conducting research to see whether our current antiviral medications could be used as antibiotics to combat bacteria - searching the rainforest for new chemicals that can be used as antibiotics - spending federal tax money to set up government labs specifically for new drug research and development

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

Over time, bacteria have become increasingly resistant to antibiotics. Which of the following best explains this in terms of natural selection? - 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. - Antibiotics caused mutations in the bacteria that were exposed to the largest doses of antibiotics. - Antibiotics caused bacteria to reproduce more quickly than normal.

True In an environment without antibiotics, individual cells probably would not differ in their reproductive rates or their survival. Without the application of the drug (antibiotic), it would be very difficult to analyze any differences—one wouldn't even be able to sort the cells.

True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics.

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

What is the concern about using antibacterial and antimicrobial soaps? - 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. - 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.

A.

Which drawing of a population of bacteria does the best job of illustrating Darwin's first postulate, that there is variation among individuals in a population? (The color red represents the ability of the bacteria to digest the sugar lactose.)

D.

Which drawing of a population of bacteria does the best job of illustrating Darwin's fourth postulate, that reproduction and/or survival are nonrandom? (The color red represents the ability of the bacteria to digest the sugar lactose.)

taking the entire course of antibiotics as prescribed by the doctor

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

Variation in beak size was present in the population of finches prior to the start of the study. Beak depth varied from 6cm to 14cm in 1975.

Which of the following is a correct application of one of Darwin's postulates to the Galapagos finch data from Case Study #2? - All the birds, no matter their beak size, were equally likely to survive during the drought. - Beak size is not a heritable trait. - All the birds, no matter their beak size, were likely to have the same number of offspring during the drought. - Variation in beak size was present in the population of finches prior to the start of the study.

The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. Bacterial cells have higher fitness when they are drug resistant in the new environment in which people have been medicated with antibiotics.

Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment? - The drug-susceptibility trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. - The drug-susceptibility trait is an adaptation to the environment of antibacterial soaps. - The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. - The drug-resistance trait is an adaptation to the environment in which human hosts travel worldwide and are exposed to new strains of bacteria.

Heritable variation exists for traits among individual in a population.

Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection? - Environmental variation exists for traits among individuals in a population. - Heritable variation exists for traits among individuals in a population. - Drug resistance exists among all individuals in a population. - Heritable variation does not exist among individuals in a population.

Individuals experience differential success in their ability to survive or reproduce due to differences in certain traits. Variation in fitness is required for selection to change the characteristics of a population over time. Remember that selection also requires that the variation in fitness be related to a heritable trait.

Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection? - Individuals experience uniform success in their ability to survive or reproduce. - Individuals experience differential success in their ability to survive or reproduce due to differences in certain traits. - Individuals experience no success in their ability to survive or reproduce. - Individuals experience unlimited success in their ability to survive or reproduce.

The last drawing.

Which of the following student drawings does the best job of illustrating Darwin's first postulate, that there is variation among individuals in a population?

Populations can evolve, but individuals cannot. Evolution is a change in the genetic makeup of a population.

Which statement is correct? Evolutionary change is not always due to genetic changes in a population over time. Natural selection can change an individual's allele frequencies. Populations can evolve, but individuals cannot. Natural selection chooses between populations, not individuals.