Charles Darwin spent much of his later life at Downe in Kent: thinking, writing and experimenting in an emphatically rural landscape. But he retained an interest in marine animals, a fascination that developed in his early years at university and during his extended voyage around the world on HMS Beagle.
Professor Phil Rainbow (Keeper of Zoology) has published a keynote presentation in the journal Marine Ecology on the influence of marine biology on Charles Darwin - and the influence of Darwin on marine biology.
Darwin made his first forays into the world of marine biology as a medical student in Edinburgh from 1825 to 1827. He came under the influence there of the Lamarckian Robert Grant, and developed an understanding of the simple organisation of the early developmental stages of marine invertebrates. Yet Darwin could not accept Lamarckian transmutation - a complex set of ideas on evolution that preceded the idea of natural selection. (Lamarck was a French scientist who, among other ideas, argued that a characteristic [such as larger muscles as a result of frequent exercise] acquired during an organism's life would be passed on to descendants and resulted in evolutionary change: Darwin's later development of natural selection as an explanation for evolution discredited Lamarck's ideas.)
The voyage of the Beagle gave him intense exposure to a wide range of marine environments around the world and led to Darwin's perceptive theory on the origin of coral reefs, an origin still mainly accepted today. This theory was linked closely to the uniformitarianism (gradual geological change over millions of years) of the geologist Charles Lyell, depending on the slow, gradual growth of billions of coral polyps keeping pace at sea level with slow sinking of land to produce an atoll.
Darwin's interest in variation in animals and plants led him to examine many different organisms, both wild and domestic. However, he was aware that his unusual scientific background meant that he had not developed a his reputation on the basis of detailed scientific study in a particular area. Therefore, from 1846 to 1854 Darwin focused on barnacle diversity and revolutionised understanding of barnacles, producing the monographs Living Cirripedia that are still relevant today.
Darwin's barnacle studies gave him the credibility to pronounce on the origin of species; he found great variation in morphology, and a series of related species with remarkable reproductive adaptation, culminating in the presence of dwarf males. Barnacles laid out an evolutionary narrative before him, and contributed greatly to his qualification and confidence to write with authority on the origin of species by 1859.
PS Rainbow (2011) Charles Darwin and marine biology. Marine Ecology. doi:10.1111/j.1439-0485.2010.00421.x