Engaging text, beautiful artwork
The romantic days of the search for the "missing link" are gone, and as science writer Carl Zimmer reminds us, that is all to the good since the very idea of a "missing link" is a misdirection. What we have today is the search for human ancestors and for a distinction to be made between our ancestors and other ancient hominids. This book with its beautiful prints and photos, engaging drawings and helpful charts, and especially the sprightly text by Zimmer brings the general reader up to date (circa 2005) on the latest developments.
There's a lot going on. There's the controversy about Homo floresiensis, thought to be a tiny hominid, found in Indonesia in 2004. Zimmer presents the arguments. Some think that Homo floresiensis is an island adaptation of Home erectus, the first hominid to make it out of Africa 1.8 million years ago. After all, island adaptation often leads to diminished size. There are fossils of now extinct small elephants in Indonesia. But others believe that the skull found is an anomaly, a case of microcephaly, a birth defect. I'm betting on the latter. [Note: since I wrote this I’ve changed my mind. From the lastest evidence that I am aware of Homo floresiensis is (probably) an island adaptation of (possibly) Home erectus.]
There are wooden spears found that are around 400,000 years old, meaning that Homo habilis or Homo ergaster (who may be one and the same) or the more recently discovered Homo heidelbergensis were accomplished tool makers long before Homo sapiens arrived on the scene. There is the idea that Homo neanderthalensis is a cold climate, European adaptation of Homo erectus. [Note: more recent evidence suggests that Homo neanderthalensis is later than Homo erectus and more closely related to us through Homo heidelbergensis.]
Part of the excitement in paleontology is in the new fossil finds, and part is in our new-found ability to analyze DNA samples to map the spread of hominids. This allows us to see the "out of Africa" phenomenon in three main stages: (1) Homo erectus leaving Africa 1.8 million years ago, followed by (2) Homo heidelbergensis expanding into not only Europe and the Near East and China, but into Southeast Asia as well. Finally (3), about 130,000 years ago, Homo sapiens begin to move out of Africa, first into the Levant and then into East Asia and Australia (50,000 years ago), then into Europe and Siberia (40,000 years ago) and ultimately into the Americas (20,000 years ago). Incidentally, this book has Homo sapiens coming onto the scene almost 200,000 years ago.
Zimmer talks about the various hominid cultures and speculates on their social and religious possibilities. On the subject of what happened to the Neanderthal, he intimates that he believes it was a combination of things that allowed humans to survive while the Neanderthals went extinct, including being better able to adapt to climate change, having a more sophisticated culture and better hunting techniques. I think it's also possible (actually I think it's likely) that humans were better at killing not only herd animals but the competition as well, meaning that one of the reasons that the Neanderthals are gone is because we killed them. Zimmer more or less skirts around this, waiting (wisely, I think) until further evidence is in.
In a final chapter, "Where Do We Go from Here?" Zimmer briefly discusses biotechnology and genetic engineering, and how our species might be affected by cultural evolution.
This is a handsome book. It's like a coffee table book with the high gloss, heavy pages and the beautiful artwork, but smaller in size. Most significantly it is a book aimed at the general reader that is well written, well edited, and very well presented. And it is clear. It is in fact the clearest book on human origins--usually a very murky subject--that I have read.
By the way, Zimmer is the author of several excellent science books. I especially recommend his creepy, but fascinating, Parasite Rex: Inside the Bizarre World of Nature's Most Dangerous Creatures (2000).
--Dennis Littrell, author of “Understanding Evolution and Ourselves”