Mastering Biology Ch. 22
Which term describes the ability of a trait to be passed on to offspring?
Heritability
Which of the following statements about natural selection is true?
*Natural selection favors individuals that reproduce more than others. -Natural selection occurs in opposition to evolution -Natural selection is a process whereby genes are selected randomly for preservation in the next generation -Natural selection can be used by farmers to generate organisms with desirable traits (Why: because individuals who are better able to survive and reproduce are more likely to be selected for than individuals who don't survive or cannot reproduce
Which of these lists contains the four postulates of natural selection?
-Variation in population -Heritable variation -Selection -Differential survival or reproduction
A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year's crop: Individual A—Yield: 179 bushels/acre; drought resistance: high Individual B—Yield: 220 bushels/acre; drought resistance: low Individual C—Yield: 185 bushels/acre; drought resistance: medium Individual D—Yield: 140 bushels/acre; drought resistance: high Individual E—Yield: 200 bushels/acre; drought resistance: medium
A & E (Why: This cross would result in an average corn yield of 189.5 bushels/acre and have a medium-high drought resistance, which is the best you can get for both traits
Which term describes a trait that increases an individual's ability to survive in a particular environment?
Adaptation
Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection?
Heritable variation exists for traits among individuals in a population. (Why: this is an accurate statement of the first two steps in the sequence of natural selection.)
Which of the following statements is an accurate combination of postulates 3 & 4 of natural selection?
Individuals experience differential success in their ability to survive or reproduce. (Why: 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. )
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 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. (Why: if all these conditions are true, then the corn borer might evolve resistance to the toxic protein.)
Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment?
The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. (Why: Bacterial cells have higher fitness when they are drug resistant in the new environment in which people have been medicated with antibiotics.)
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.
True (Why: In an environment without antibotics, individual cells probably would not differ in their reproductive rates of 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!)
Which of the following organisms could be produced by artificial selection>
*A cow that produces a large quantity of milk (Why: A cow's ability to produce milk is a heritable trait that can be manipulated by artificial selection)
Which pair of chickens should a farmer breed to produce larger chickens?
Large hen, large rooster (Why: Large parents should be bred to produce larger offspring)
Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype?
No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host. (Why: a cell's drug susceptibility of 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.)