On the Origin of Species

For decades before its rise in the 1860s, natural selection theory was highly controversial as a viable basis for biological science because it directly countered the prevalent view on species origin—independent creation theory. Darwin notes in On the Origin of Species that every eminent scientist in his field—including himself—held the latter view, though they had varied explanations for how it occurred. As a young naturalist, Darwin followed Charles Lyell, his intellectual hero, future friend, and author of Principles of Geology.

The natural selection theory that Darwin proposed was the product of nearly two decades of gestating ideas, many of which arose during his expedition around the world aboard the HMS Beagle. Over the five-year period (1831-1836) of this voyage, Darwin, enlisted as the expedition’s naturalist, took extensive notes on zoology and geology. The Beagle circumnavigated the globe, stopping for extended periods on multiple continents in the southern hemisphere. Lyell’s Principles of Geology was Darwin’s constant companion.

Of the many places that left a distinct impact on Darwin’s coming-of-age as a naturalist, the Galapagos Islands (an archipelago in the Pacific Ocean west of Ecuador) was the most notable. Among other firsts, Darwin noted that each of four closely situated islands had a unique