Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as
the outcome of a tradeoff: webbed feet perform poorly on land, but are very helpful in diving for food
Darwin found that many of the species on the Galápagos islands
resembled species on the nearest mainland.
Lyell's book Principles of Geology, which Darwin read on board the H.M.S. Beagle, argued in favor of which of the following concepts?
Earth's surface is shaped by natural forces that act gradually and are still acting.
The human immune system cannot effectively suppress the HIV virus on its own. What key feature of HIV makes it so hard to beat?
The HIV virus has an extremely high rate of mutation.
Imagine that four people are infected with HIV from a common source (an infected blood sample). Initially, the patients' HIV populations are genetically identical. By the time they develop full-blown AIDS, how would the viral populations of the four patients compare?
Each patient's viral population would be unique, specifically adapted to deal with—and overcome—his or her unique immune system responses.
As proposed by Darwin, what sorts of traits are favored by natural selection?
Heritable traits that help individuals survive and reproduce more successfully than others in the same population
Natural selection is best described as
a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations
HIV has become an important source of mortality for humans. If AIDS persists as a major factor for humans for many generations in the future, natural selection theory predicts tha
any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time
Which of the following statements would Darwin have disagreed with?
Descent with modification occurs through inheritance of acquired characteristics
During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold, they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and natural selection, do you think this project worked as planned?
No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring
Broccoli, cabbages, and brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by
Which of the following best expresses the concept of natural selection?
differential reproductive success based on inherited characteristics
Which of the following assumptions or observations is not part of Darwin's idea of natural selection?
Whether an organism survives and reproduces is almost entirely a matter of random chance
Which of the following thinkers argued that much of human suffering was the result of human populations increasing faster than food supply, an argument that later influenced Charles Darwin's ideas of natural selection?
A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs. Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog breeds. Which of the following would be a logical explanation for her failure?
The tendency to bark is not a heritable trait
Which of the following would prevent an organism from becoming part of the fossil record when it dies?
It is fully decomposed by bacteria and fungi
Which of the following statements regarding the currently available fossil record is false?
The currently available fossil record shows that the first life forms were eukaryotes.
Which of the following disciplines has found evidence for evolution based on the native distributions (locations) of living species?
Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of