Through most of the eighteenth and nineteenth centuries, scientists believed that the adaptations of every organism on earth were evidence of a divine plan, a plan that, for most, ended and began with man. People tended to indulge in a human-oriented view of life. Many believed, for instance, that horses’ backs were shaped simply to give man a comfortable seat for riding; that seawater contained alkaline substances like magnesia and lime so sailors could clean their clothes without using soap; that tides existed just to help the ships come in.
