Birds are descended from dinosaurs. But there is a lot of history to that idea. Paleontologists did not simply uncover fossils of dinosaurs and realize that living birds are a surviving lineage of theropods. Where can one turn to learn of all this? Brian Switek, whose blog Laelaps (in its current evolutionary stage with Wired) I have been reading for several years now, has just published his first book, Written in Stone. Each chapter focuses on a particular group of animals that we now have great fossil evidence showing their evolutionary history: birds, whales, early rodent-like mammals, elephants, horses, and humans, to name a few. We come away with a full understanding of the branching nature of the evolution of life on Earth, as Switek dispels the notion of progressive, ladder-like, and human-oriented evolution. He also gives us the sense of the vast amount of extinct vertebrates (relatives of ours included), for some of what we see on the planet today - horses, for example - are just a peek of the diversity of forms in the groups in which they are nested. "To focus solely upon our ancestors is to blind ourselvves to our own evolutionary context" (21).
Wielding a wealth of science information while attending to historical detail, Written in Stone offers a very-readable narrative of how European and American scientists have understood fossils over the centuries. While not an academic historian - he is a freelance science writer and a Research Associate in paleontology at the New Jersey State Museum - Switek gives importance to the historical development of ideas in paleontology. Here we are introduced to not only various species of vertebrate animals and the myriad of transitional forms bridging them, but also to their discoverers and the thoughts of those who have studied them (in some cases, this includes indigenous peoples, with a nod to the work of Adrienne Mayor, The First Fossil Hunters: Dinosaurs, Mammoths, and Myth in Greek and Roman Times (New in Paper) and Fossil Legends of the First Americans).
One of the criticisms Darwin knew he would receive on publishing On the Origin of Species was that the fossil record was incomplete. Maybe so, but move ahead in time a century and a half, and the amount of material evidence for past life on earth is remarkable, thousands upon thousands of specimens across the kingdoms packed away or lining cabinet drawers in museum collections worldwide, a minute percentage on view to the public. Despite what we do have, it will never be complete, and the answers to paleontologists' questions about what animal is related to another, and how are those in turn related to this group will never be, well, set in stone. Like any field of science, paleontology is an ongoing human process. Ideas are constantly refined based on new evidence or someone coming along and looking at things differently. In Written in Stone, Switek shows us that in paleontology, this is definitely the case.
There are generally two ways we could look at the history of paleontology. One, as Switek does, is to tell the story of those involved (we get Darwin, Huxley, Owen, Marsh, and Cope, but we also learn about a lot of relatively unknowns, too, such as Albert Gaudry; and there's a female paleontologist as well, Jennifer Clack), their ideas, conflicts and competition between figures, and the contingent nature of history - this happened, so therefore this happened; or, this only happened because this happened. We receive such history for the early nineteenth century all the way up to, well, now. Just as evolution is contingent, certain events can happen that change the course of paleontological history. For example, Switek tells us about how only when a graduate student dropped a specimen did that act help to understand the evolutionary history of whales. Today, CT scanning is the norm in paleontology for peering into the insides of bones. Before, such were chance opportunities, or, deliberative slicing of specimens.
The other, which Switek acknowledges but does to a lesser degree (but he does get some in there!), is to show how factors seemingly beyond the purview of science actually inform it, and vice versa (how culture, politics, economics, geography, etc. play a role in the conduct of science). "The places paleontologists looked for fossils and how those fossils have been interpreted have been influenced by politics and culture, reminding us that while there is a reality that science allows us to approach the process of science is a human endeavour" (23). Covering so much about geology, the age of the earth, and fossils of animals, Switek shows how religion affected the ideas of some naturalists or paleontologists. We learn how politics enabled naturalists to travel, "natural science, pressed into the service of empire" (69, 181, 183); of the public's thirst for spectacles (145); how national pride pitted Thomas Jefferson against the Comte de Buffon concerning large mammals in North America; and how Philip Henry Gosse attacked evolution because of personal reasons (204-5).
And, so what? Does it matter if we understand how life on Earth evolved? Yes, it surely does, since we are part of that story. In the last two pages of the penultimate chapter and in the short final chapter, Switek pulls his thoughts together and unpretentiously puts us in our place. "We are merely a shivering twig that is the last vestige of a richer family tree." If that saddens you, then: "Life is most precious when its unity and rarity are recognized, and we are among the rarest of things." Humans are just like any other organism on the planet, and all should be appreciated together.
There have been several books over the last few years that look at the evidence for evolution (particularly, Richard Dawkins's The Greatest Show on Earth: The Evidence for Evolution, Jerry Coyne's Why Evolution Is True, and another to be published next June, The Evidence for Evolution by Alan R. Rogers). What value, then, is Written in Stone? One, because it is so very well-written by a young writer. And two, for its coverage of the history of science, however limited. Three, it is the perfect antidote to the ignorance of some members of our society [largely creationists; however, Switek does not explicity engage with anti-evolutionists in his book, rather, his text works as "letting the evidence speak for itself," or, as Switek states, "the bones of our distant ancestors... should speak to us from the earth" (18)].
That said, Mr. Switek, congratulations on writing a fantastic book about evolution, which I think could be titled Strange Beings à la Darwin (Hugh Falconer referring to Archaeopteryx in a 1863 letter to Darwin, which Switek quotes in the book). I look forward to meeting you at Science Online 2011 in January! (Switek also blogs for Smithsonian's Dinosaur Tracking Blog.)
