In his thirty-three-page essay, accompanied by the sort of splendid photography for which National Geographic is famous, Quammen argues:
Evolution is both a beautiful concept and an important one, more crucial nowadays to human welfare, medical science, and to our understanding of the world than ever before. It's also deeply persuasive -- a theory you can take to the bank. The essential points are slightly more complicated than most people assume, but not so complicated that they can't be comprehended by any attentive person. Furthermore, the supporting evidence is abundant, various, ever increasing, solidly interconnected, and easily available in museums, popular books, textbooks, and a mountainous accumulation of peer-reviewed scientific studies. No one needs to, and no one should, accept evolution merely as a matter of faith.Although the complete essay is not available on-line, the National Geographic web site contains excerpts as well as extra features such as field notes, links, and a bibliography.