Biology Chapter 15

How is the idea of common descent supported by examples of homologous structures?

In their mature forms, homologous structures, such as bird wings and mammal forelimbs, appear somewhat different, but they develop from the same kind of embryonic tissues. From this evidence, scientists infer that the particular species evolved from a common ancestor population that moved into different environments, where the populations were changed through natural selection.

Discuss Lamarck's contribution to the overall theory of evolution.

Lamarck was among the first to recognize that living things changed over time and that organisms were adapted to their environments. Lamarck's explanation for the process of evolution, however, was incorrect.

Can you tell from Figure 15-1 how closely the three tortoise species resemble the ancestral species? Why or why not?

No, the diagram does not provide information on the ancestral species.

Were Darwin's hypotheses about natural selection and evolution similar to the ideas of most other scientists of his time? Explain.

No; Darwin's hypotheses challenged the fundamental scientific ideas of the times.

Considering the body structures of the tortoises shown in Figure 15-1, which tortoises—a population from Pinta Island or a population from Isabela Island—might survive more successfully on Hood Island? Why

The Pinta Island tortoises likely would survive more successfully because they appear to be more similar to the Hood Island tortoises.

Suppose that selective breeding has produced a population of very similar chickens. Would that population survive if it were released into the world? Explain.

The population's survival would depend on how well adapted its members were to the new environment. If they were not well adapted, the population would probably not survive because it would have so little variation.

What differences are apparent in the bodies of the three tortoise species shown in Figure 15-1?

The tortoises have necks of different length and shells that differ in overall shape and in the size of the opening for the neck.

What did Darwin learn about the land tortoises of the different Galápagos Islands?

The tortoises varied from island to island in predictable ways, such as shell shape and neck length.

.​Lamarck proposed that organisms a. have an innate tendency toward complexity and perfection. b. have an innate tendency to become more simple as time passes. c. inherit all of the adaptations they display. d. belong to species that never change.

a. have an innate tendency toward complexity and perfection

Darwin's theory of evolution is based on the idea(s) of a. natural variation and natural selection. b. use and disuse. c. a tendency toward perfect, unchanging species. d. the transmission of acquired characteristics.

a. natural variation and natural selection

​The number and location of bones of many fossil vertebrates are similar to those in living vertebrates. Most biologists would probably explain this fact on the basis of a. the needs of the organisms. c. the struggle for existence. b. a common ancestor. d. the inheritance of acquired traits.

b. a common ancestor

​Darwin viewed the fossil record as a. evidence that Earth was thousands of years old. b. a record of evolution. c. interesting but unrelated to the evolution of modern species. d. evidence that traits are acquired through use or disuse.

b. a record of evolution

The species of tortoises that Darwin found on the Galápagos Islands displayed different structural adaptations. One of the adaptations that Darwin noted was the a. similarity in the tortoises' embryos. b. difference in shell markings of the tortoises. c. variation in length of the tortoises' necks. d. difference in number of eggs in each tortoise's nest.

b. difference in shell markings of the tortoises

​Darwin's concept of evolution was NOT influenced by a. the work of Lyell. b. knowledge of the structure of DNA. c. his collection of specimens. d. his trip on the H.M.S. Beagle.

b. knowledge of the structure of DNA

Darwin began to formulate his concept of evolution by natural selection after a. experimentation with animals. b. observations of many species and their geographical locations. c. reading the writings of Wallace. d. agreeing with Lamarck about the driving force behind evolution.

b. observations of many species and their geographical locations

Lamarck's theory of evolution includes the concept that new organs in a species appear as a result of a. continual increases in population size. b. the actions of organisms as they use or fail to use body structures. c. an unchanging local environment. d. the natural variations already present within the population of organisms.

b. the actions of organisms as they use of fail to use body structures

​One scientist who attempted to explain how rock layers form and change over time was a. Thomas Malthus. b. Charles Darwin. c. James Hutton. d. Jean-Baptiste Lamarck.

c. James Hutton

The idea that only famine, disease, and war could prevent the endless growth of human populations was presented by a. Darwin. c. Malthus. b. Lamarck. d. Lyell.

c. Malthus

On the Galápagos Islands, Charles Darwin observed a. completely unrelated species on each of the islands. b. species exactly like those found in South America. c. somewhat similar species with traits that suited their particular environment. d. species completely unrelated to those found in South America.

c. somewhat similar species with traits that suited their particular environment

When lions prey on a herd of antelope, some antelope are killed and some escape. Which part of Darwin's concept of natural selection might be used to describe this situation? a. acquired characteristics c. survival of the fittest b. reproductive isolation d. descent with modification

c. survival of the fittest

Which concept is NOT included in the modern theory of evolution? a. descent with modification b. natural selection c. transmission of acquired characteristics d. competition among the members of a population

c. transmission of acquired characteristics

​When Darwin returned from the voyage of the Beagle, he a. immediately published his ideas about evolution. b. realized his ideas about evolution were wrong. c. wrote about his ideas but waited many years to publish them. d. copied the evolutionary theory of Wallace.

c. wrote about his ideas but waited many years to publish them

According to Darwin's theory of evolution, all species on Earth are united by _________________________.

common descent

According to Darwin's theory of natural selection, the individuals that tend to survive are those that have a. characteristics their parents acquired by use and disuse. b. characteristics that plant and animal breeders value. c. the greatest number of offspring. d. variations best suited to the environment.

d. variations best suited to the environment

Darwin proposed that natural selection takes place as individuals best suited to the ____________________ survive and reproduce.

environment

Although his idea was incorrect, Lamarck was one of the first people to propose a scientific explanation for ____________________.

evolution

Hutton and Lyell held similar views about Earth's age. Both thought that Earth was ____________________ of years old.

millions

Darwin concluded that in similar environments around the world, _________________________ could produce similar structures in unrelated species.

natural selection

Which of the tortoises shown in Figure 15-1 has the longest neck?

the Hood Island tortoise

Modern whales have a vestigial pelvis and femur. What does this evidence suggest about ancestors of modern whales?

Ancestors of modern whales likely had legs and lived on land.

Vegetation on Hood Island is sparse and sometimes hard to reach. How might the vegetation have affected the evolution of the Hood Island tortoise shown in Figure 15-1?

Ancestral tortoises with long necks and shells that permit greater neck movement obtained food more easily, survived longer, and produced more offspring than other tortoises.

Explain how Darwin's observation of the tortoises on the Galápagos Islands influenced his thinking.

Darwin began to think that the varied tortoise species on the islands had evolved from a single tortoise species from the mainland.

​What was the scientific value of the specimens that Darwin brought back to England?

Darwin collected many examples of similar, but not identical, modern organisms and fossils that were previously unknown.

What was Darwin's greatest contribution to science, and how did he develop it?

Darwin made a wealth of observations about the natural world and developed a hypothesis that became the theory of evolution. He explained that species change over time through natural selection: the survival and reproduction of those members of a population that best suit their environment.

In what way did the voyage of the Beagle provide Darwin with an ideal opportunity for collecting and analyzing data?

Darwin was able to collect specimens from many different places where the ship anchored, and while he was at sea, he could record his observations.