Section 15-3: Darwin Presents His Case

*What is true about Darwin's book "On the Origin of Species"?*

A. It contained evidence for evolution. B. It described natural selection.

*What is true about artificial selection?*

A. It is also called selective breeding. B. It occurs when humans select natural variations they find useful. C. It produces organisms that look very different from their ancestors.

*What is true about natural selection?*

A. It selects traits that increase fitness. B. It takes place without human control.

*Evidence for Evolution can be found in what?*

A. The fossil record. B. The geographic distribution of living species. C. Homologous structures of living organisms. D. Similarities in embryology.

*What is part of Darwin's theory of evolution?*

A. There is variation in nature. B. There is a struggle for existence. C. Species change over time.

*The naturalist whose essay gave Darwin an incentive to publish his own work was who?*

Alfred Russel Wallace.

*What is adaptation?*

Any inherited characteristic that increases an organism's chance of survival.

*The principle that all species were derived from common ancestors is known as what?*

Common descent.

*How did Darwin explain the existence of similar but unrelated species?*

Darwin thought that such species evolved features in common because they were exposed to similar pressures of natural selection.

*Darwin believed that all organisms on Earth are united into a single tree of life by what?*

Descent with modification.

*The principle that living species descend, with changes, from other species over time is referred to as what?*

Descent with modification.

*Is the following sentence true or false? Adaptations can be physical characteristics but not more complex features such as behavior.*

False.

*Is the following sentence true or false? Darwin argued that living things have been evolving on Earth for thousands of years.*

False.

*Is the following sentence true or false? Genetic variation is found only in wild organisms in nature.*

False.

*Is the following sentence true or false? When Darwin returned to England, he rushed to publish his thoughts about evolution.*

False.

*What was Darwin's greatest contribution?*

His greatest contribution was developing a scientific hypothesis to explain how evolution occurs.

*Structures that have different mature forms but develop from the same embyronic tissues are called what?*

Homologous structures.

*Explain what Darwin meant by the phrase "survival of the fittest".*

Individuals that are better suited to their environment survive and reproduce most successfully.

*What does the phrase "struggle for existence" mean?*

It means that members of each species compete regularly to obtain food, living space, and other necessities of life.

*According to Darwin's theory, what happens to individuals whose characteristics are not well suited to their environment?*

Such individuals die or leave fewer offspring.

*What is natural selection?*

Survival of the fittest.

*What is fitness?*

The ability of an individual to survive and reproduce in its specific environment.

*How do fossils that formed in different rock layers provide evidence of evolution?*

They document the fact that life on Earth has changed over time.

*What is the way Darwin explained the distribution of finch species on the Galápagos Islands?*

They had descended with modification from a common mainland ancestor.

*What is the status of Darwin's hypotheses today?*

They have been confirmed and expanded by scientific advances in biology, geology, and physics.

*Is the following sentence true or false? Homologous structures provide strong evidence that all four-limbed vertebrates have descended, with modifications, from common ancestors.*

True.

*Differences among individuals of a species are referred to as what?*

Variation.

*Organs that are so reduced in size that they are just vestiges, or traces, of homologous in other species are called what?*

Vestigial organs.