Niles Eldredge - The Darwin Blogs

The Darwin Blogs – March 12, 2006.

The Darwin Exhibition #2. Creationism—and The Power of Comparative Anatomy.

Charles Darwin was born in 1809 into a world that thought the Biblical account of the origin of the earth and the history of life are essentially correct: that the earth is less than 10,000 years old, and that species are created separately and look today pretty much as they did when they were first created. The entire purpose of the exhibition is to explore what Darwin saw—in his early life, and especially while on the voyage of H.M.S. Beagle (1831-1836)—and what his reading, experiments and observations led him to think upon his return to England. It is this evidence for evolution—including the survey of modern evolutionary biology near the end of the exhibition—that forms the very heart of the Darwin exhibition. (As a reminder: you can see images of the exhibition, and read text, at http://www.amnh.org/exhibitions/darwin/).

The exhibition opens with a single, simple object: one of Darwin’s magnifying glasses. (It is good that the magnifying glass comes with a case—which is genuinely decrepit and old-looking; otherwise Darwin’s glass looks like something you could buy at Staples today!). The magnifying glass symbolizes the entire exhibition. Here was a young man (we are saying in the Introduction) who, with little formal scientific training, and with relatively simple tools (think how a magnifying glass compares with a modern electron microscope!) managed to come up with one of the most important ideas—not just in biology, or even all of science—but in terms of the entire history of human western-world thought. We want to tell especially our young, student visitors that science is basically an adventure of a single human mind resonating with patterns in the natural world. Darwin was able to achieve what he did, not just because he was very bright, and was in the right place at the right time (that Beagle voyage especially—see forthcoming blogs), but because he kept an open mind and was able to “let nature come to him” (in the words of my colleague at the American Museum of Natural History, ornithologist Joel Cracraft). It was keeping his eyes and mind open—and working very hard—that enabled Darwin to see what others covering the same route and having similar experiences in the natural world before him could never quite grasp.

Except a few. The first room in the exhibition is our “creationist” room. It is the intellectual “world before Darwin.” When Darwin was born in 1809, there was really no professional class of scientists yet. Rather, leisured wealthy men and clergymen for the most part were the early contributors to the growth of scientific knowledge. And a few of these—I think most notably Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (“Lamarck” for short!)—had already formulated some serious ideas about evolution.

Lamarck was a zoologist, and made great contributions to the early study especially of “invertebrate” animals—that great hodge-podge of animals that mostly share the lack of a backbone in common. Things like the sponges (most people don’t even know sponges are animals—but they are—though they lack true tissues and organ systems); corals and “jellyfish”; flatworms; mollusks (clams, snails, squids, etc.); arthropods (lobsters, insects, spiders, millipedes, etc.), echinoderms (starfish, sea urchins, etc.); annelid worms (earthworms, leeches, some marine worms), etc. etc. Lamarck saw all these as forming part of the “Great Chain of Being.” And he thought they were all inter-related by a process of ancestry and descent—the core idea of evolution. You can think of evolution as the simple idea that all organisms on the face of the earth right now are descended from a single common ancestor (now known to have lived at least 3.5 billion years ago). And, to jump ahead to a lesson Darwin actually taught us, you can “test” this idea of evolution scientifically by predicting what you might see were it true. If evolution is true, there ought to be at least one feature held in common by all organisms—from the simplest of bacteria to the most complex of plants and animals. And there is such a feature: the amazing molecule of heredity known as RNA. Given the logic of scientific discovery and analysis, RNA does not prove that all organisms are descended from a single common ancestor; but if RNA were not common to all life, the idea of evolution in the sense I am using it here would be on far shakier scientific ground.

But most scientists of the 18th century were decidedly not evolutionists. Our “world before Darwin” room is decorated with images of plates (paintings and drawings from early zoological and botanical monographs) such as decorated some of the walls of the house of famous Swedish naturalist Carl von Linné—better known as Linnaeus. Linnaeus published his Systema Naturae—the publication setting forth his principles of classification, the famed “Linnaean hierarchy” still in use today—in 1758. Early naturalists such as Linnaeus saw there are patterns of similarity linking up obvious groups of what they called “allied” animals and plants. For example, the foxes of Europe look a lot like dogs—as do wolves. As the early days of exploration began to send specimens of animals and plants back to Europe, other distinct forms (“species”) of dog-like animals were found and recognized. Dog-like animals are all classified together in the Family Canidae. But observant naturalists such as Linnaeus also saw that dogs share with cats and other cat-like species (Family Felidae) certain features—especially of the meat-eating scissor-like shearing molar teeth. With bears, raccoons, and weasels, cats and dogs are further classified into the Order Carnivora (of the Class Mammalia—which all share hair and mammary glands).

But this “natural system” did not suggest to Linnaeus that life has evolved. Rather (despite one or two hints to the contrary later in life), Linnaeus stuck to prevailing wisdom that species are all separately created—by God. They believed (as the Bible suggests) that the earth is relatively young, and that species were created more-or-less in their present form a relatively short time ago. Linnaeus was the exception to the general creationist rule.

We illustrate these themes in the “World Before Darwin” segment with a genuine Victorian-age wood and glass display case (augmented with modern steel work inside) crammed with an array of vertebrate skeletons. Dominating this rather small space, the case reflects the fact that, evolution or no, 18th century scientists were noticing similarities in the anatomies of different species and using these similarities to classify organisms. Nothing brings this home more clearly, directly and powerfully than seeing skeletons of various different mammals displayed side-by-side.

Indeed, this case has such an effect on our visitor’s imaginations that, in the very room where we explore the prevailing pre-Darwinian creationist viewpoint, our illustration seems in many instances to be having the opposite effect. The best story I know about this comes from my son Gregory, who teaches science in the Bronx. Greg brought his class to the exhibition right after it opened. One of his students asked if that was the skeleton of a young chimpanzee that Greg had mentioned before they got there. Greg said “yes”—and his student said (I love this!): “That’s it right there! I don’t have to see anything else—I get it!”

He got it—in the very room devoted to creationist beliefs in the world before Darwin (and a world that persists to this day, of course)! We use comparative anatomical displays at several other places in the exhibition—because (as Darwin told us) these similarities MUST be there if evolution is true! You should see the bones of a whale’s flipper near the end of the exhibition—looks just like a gigantic, and just a bit proportionately distorted, human arm!!!!

Next time we’ll begin exploring the life, times, and experiences of the young Charles Darwin as he begins his journey that in the end would revolutionize our thinking about life—and about who we humans are and how WE got here in the first place!

Niles Eldredge

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