21. Evolution

Darwin originally defined evolution as __________.

Which of the following is a key observation that must be explained in a unifying theory about life?

The scala naturae, or scale of nature, is based on the ideas of __________.

At the time Darwin voyaged on HMS Beagle, the popularly accepted theory in Western culture that explained the origin of Earth's plants and animals held that the various species __________.

What observations did Darwin make on the Galápagos Islands that helped convince him that evolution occurs?a. the existence of animals that did not fit into Linnaeus's classification system;b. the similarities and differences among cacti and tortoises on the different islands;c. the presence of species he had seen on other tropical islands far from the Galápagos;d. the radioactive age of the rocks of the islands;e. fossils of human ancestors

Which of the following is an observation or inference on which natural selection is based? (A) Individuals do not vary in their heritable characteristics. (B) Only well-adapted individuals produce offspring. (C) Species produce more offspring than the environment can support. (D) Nearly all of each individual's offspring will survive and reproduce.

Which of the following is not an observation or inference on which natural selection is based?a. There is heritable variation among individuals.b. Poorly adapted individuals never produce offspring.c. Species produce more offspring than the environment can support.d. Only a fraction of an individual's offspring may survive.

Summarize the key points of Darwin's theory of descent with modification, including his proposed mechanism of evolution.