What types of drugs have helped reduce the death rate due to tuberculosis infection, and why have they become less effective more recently?

Which of the following observations is not part of the theory of natural selection?

a. Populations of organisms have more offspring than will survive

b. There is variation among individuals in a population

c. Modern organisms are unrelated

d. Traits can be passed on from parent to offspring

e. Some variants in a population have a higher probability of survival and reproduction than other variants do

The best definition of evolutionary fitness is:

a. Physical health

b. The ability to attract members of the opposite sex

c. The ability to adapt to the environment

d. Survival and reproduction relative to other members of the population

e. Overall strength

An adaptation is a trait of an organism that increases:

a. Its fitness

b. Its ability to survive and replicate

c. In frequency in a population over many generations

d. A and B are correct

e. A, B, and C are correct

The heritable differences among organisms are a result of:

a. Differences in their DNA

b. Mutation

c. Differences in alleles

d. A and B are correct

e. A, B, and C are correct

Since the modern synthesis, the technical definition of evolution is a change in allele frequency in a population over the course of generations.

a. Traits, species

b. Allele frequency, population

c. Natural selection, natural environment

d. Adaptations, single organism

e. Fitness, population

Ivory from elephant tusks is a valuable commodity on the world market. As a result, male African elephants with large tusks have been heavily hunted for the past few centuries. Today, male elephants have significantly shorter tusks at full adulthood than male elephants in the early 1900s. This is an example of:

a. Diversifying selection

b. Stabilizing selection

c. Directional selection

d. Chance

e. More than one of the above is correct

Antibiotic resistance is becoming common among organisms that cause a variety of human diseases. All of the following strategies help reduce the risk of antibiotic resistance evolving in a susceptible bacterial population except:

a. Using antibiotics only when appropriate, for bacterial infections that are not clearing up naturally

b. Using the drugs as directed, taking all the antibiotic over the course of days prescribed

c. Using more than one antibiotic at a time for difficult-to-treat organisms

d. Preventing natural selection by reducing the amount of evolution the organisms can perform

e. Reducing the use of antibiotics in non–health-care settings, such as agriculture