The modern idea of extinction as a common occurrence in Earth's history was first proposed in the early-19th-century writings of __________.

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 __________.

Carolus Linnaeus is considered to be the founder of __________, and he __________.

Lyell's principle of uniformitarianism __________.

Which of the following is a true statement about Charles Darwin?

At the time Charles Darwin sailed on HMS Beagle, __________.

Because he was well aware of the effect his theory of evolution would have on the public and on the Church of England, Darwin delayed publishing his work for several decades while he gathered additional evidence. After invoking selective breeding of domesticated species as evidence that groups of organisms are capable of change, he then proposed that natural populations can change as well. On which two lines of evidence did he base this proposal?