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Problem 1
True or false? Some traits are considered vestigial because they existed long ago.
Problem 2
Why does the presence of extinct forms and transitional features in the fossil record support the pattern component of the theory of evolution by natural selection? Select True or False for each statement.
T/F It supports the hypothesis that individuals change over time.
T/F It supports the hypothesis that weaker species are eliminated by natural selection.
T/F It supports the hypothesis that species evolve to become more complex and better adapted over time.
T/F It supports the hypothesis that species change over time.
Problem 3
Traits that are derived from a common ancestor, like the bones of human arms and bird wings, are said to be .
- Traits that are derived from a common ancestor, like the bones of human arms and bird wings, are said to be .
Problem 3
Problem 4
How can evolutionary fitness be measured? Select True or False for each statement.
T/F Document how long individuals survive.
T/F Count the number of healthy, fertile offspring produced.
T/F Determine which individuals are strongest.
T/F Determine which phenotype is the most common.
Problem 5
According to data presented in this chapter, which of the following are correct? Select True or False for each statement. T/F When individuals change in response to challenges from the environment, their altered traits are passed on to offspring. T/F Species are created independently of each other and do not change over time. T/F Populations—not individuals—change when natural selection occurs. T/F The traits of populations become more perfect over time.
- Explain the logic behind the claim that the nuclear envelope is a synapomorphy that defines eukaryotes as a monophyletic group.
Problem 5
Problem 6
Some biologists summarize evolution by natural selection with the phrase "mutation proposes, selection disposes." Mutation is a process that creates heritable variation. Explain what the phrase means.
Problem 7
Why don't the biggest and strongest individuals in a population always produce the most offspring?
a. The biggest and strongest individuals always have higher fitness.
b. In some environments, being big and strong lowers fitness.
c. Sometimes the biggest and strongest individuals may choose to have fewer offspring.
d. Sometimes the number of offspring is not related to fitness.
- Explain why the overprescription of antibiotics by doctors, or the overuse of everyday soaps containing antibiotics, can be a health risk.
Problem 8
Problem 9
Coral reefs are biodiverse ecosystems that provide food, income, coastal protection, and many other services to millions of people. Yet coral reefs are under threat from human impacts such as climate change—many corals cannot tolerate the warming ocean water and have suffered massive 'bleaching' events, which can be fatal. Researchers have discovered that some corals have the capacity to acclimatize to warmer water, while other corals do not. The researchers fear that because corals are long-lived colonial animals and thus evolve slowly, they may not be able to adapt to global warming fast enough to avoid extinction. Explain how the difference between acclimatize and adapt is important to the fate of corals.
Problem 10
The geneticist James Crow wrote that successful scientific theories have the following characteristics: (1) They explain otherwise puzzling observations; (2) they provide connections between otherwise disparate observations; (3) they make predictions that can be tested; and (4) they are heuristic, meaning that they open up new avenues of theory and experimentation. Crow added two other elements of scientific theories that he considered important on a personal, emotional level: (5) They should be elegant, in the sense of being simple and powerful; and (6) they should have an element of surprise. How well does the theory of evolution by natural selection fulfill these six criteria?
- Most mice living on the mainland of Florida are brown, but the mice that live on the sand dunes of the barrier islands have white fur. The differences in color are heritable, determined by genes such as MC1R. It is intuitive that the light color of beach-dwelling mice is an adaptation for blending into their environment—and thus evading predators. Compare how evolution by inheritance of acquired characters and the theory of evolution by natural selection would explain the observation of white mice living primarily on light soil and brown mice living primarily on dark soil.
Problem 11
Problem 12
What is an evolutionary adaptation?
a. A trait that improves the fitness of its bearer, compared with individuals without the trait
b. A trait that changes in response to environmental influences within the individual's lifetime
c. The ability of an individual to adjust to its environment
d. A trait that an individual wants so that it can survive
Problem 13
Most mice living on the mainland of Florida are brown, but the mice that live on the sand dunes of the barrier islands have white fur. The differences in color are heritable, determined by genes such as MC1R. It is intuitive that the light color of beach-dwelling mice is an adaptation for blending into their environment—and thus evading predators. Apply Darwin's four postulates to a population of mice living on sand dunes in coastal Florida.
- A team led by evolutionary biologist Hopi Hoekstra set out to test the hypothesis that predators are an agent of natural selection on mouse color. They made 250 plasticine models of mice that were alike in every way except that half were painted white and half were painted brown. Suggest one advantage and one disadvantage of using model mice instead of real mice in this experiment.
Problem 14
- The researchers placed white and brown mouse models both in abandoned fields on the mainland (dark soil) and on sand dunes on the islands (light soil) and then measured the percentage of models that were attacked by predators. What is the take-home message of the data? Do the data support or reject the hypothesis that mouse color is adaptive?
Problem 15
