Exam 16: An Introduction to Evolution: Charles Darwin, Evolutionary Thought, and the Evidence for Evolution

Darwin was influenced by an essay on human population and food supply written by:

John Endler's experiment with guppies demonstrates which of the following in regard to evolution through natural selection?

The half-life of a radioactive isotope is 10,000 years. This isotope and its breakdown product do not normally occur together before molten rock cools and becomes solid. You analyze a volcanic rock and find 25 percent of the original amount of radioactive isotope remains, and 75 percent has decayed to its daughter element. How long ago did the rock solidify?

Who is credited with first providing conclusive evidence of species extinction?

Darwin found that many different species of finches were found on the Galapagos Islands and nowhere else. The finches were related to a species found on the mainland of South America. From this he concluded:

For natural selection to occur, there must be competition for resources, competition for survival, or different reproductive success. Why is this so?

Scientists may compare similar genes in different species and determine what percentage of base pairs is identical. From this, it can be estimated how long ago the two species shared a common ancestor. The validity of this conclusion depends on an important assumption. This assumption is that:

A population of grasshoppers in the Kansas prairie has two color phenotypes, green and brown. Typically the prairie receives adequate water to maintain healthy green grass. Assume a bird that eats grasshoppers moves into the prairie. How will this affect the natural selection of grasshoppers? How might this change in a drought year?

What determines which traits will be passed on to the next generation in the greatest frequency?

Charles Darwin and Alfred Russel Wallace both realized that most species produce many more offspring than is necessary to maintain a constant population. What might be the fate of the excess individuals?

A well-known example of natural selection in action is the change in the peppered moth population in England in the nineteenth century. The moths blended in with their light-colored natural surroundings, but with increasing industrialization in England, smoke began to pollute the foliage and darken the trees and rocks. Eventually, populations that were once mostly light colored became mostly dark colored. Using natural selection, propose a hypothesis that would explain why the moth population changed over time from mostly light colored to mostly dark colored.

Refer to the scenario below and then answer the following question(s). In a fossil bed, you discover the preserved bones of a winged animal mixed in with the bones of small rodents. The small rodents are known from other fossils to have lived about two million years ago, but they are now extinct. -You examine the fossilized remains of the winged animal. Impressions in the surrounding rock suggest that the wings may have been covered with tiny hairs, which suggests that the animal is likely to have been a mammal. When you examine the remains of the wings, which of the following observations would be most surprising?

The various lines of evidence for evolution together support the core principles of evolution because:

Long before Charles Darwin, Jean-Baptiste de Lamarck understood all of the following ideas about evolution except that:

What mechanism did Charles Darwin discover as the driving force behind evolution?

After considerable effort, you are able to collect and analyze DNA from the winged animal. You obtain the nucleotide sequence of the cytochrome c oxidase gene. When you compare this sequence to the sequence of the same gene in a bat, a rodent, a shrew, and a human, you find the following numbers of differences: winged animal-bat 11 differences Winged animal-rodent 14 differences Winged animal-shrew 15 differences Winged animal-human 9 differences Which hypothesis does this data support?

Refer to the figure below, and then answer the question that follows. -There are fewer differences in the base sequence of the cytochrome c oxidase gene between humans and chimpanzees than there are between humans and pigs. What evolutionary relationship can you hypothesize from this?

The longer two populations are kept from interbreeding, the:

The major weakness of Charles Darwin's theory during his lifetime was the:

Pharyngeal slits are present in the embryos of organisms as diverse as fish, chickens, and humans. Why would organisms as different as these have similar embryonic structures?