Biologist Stanley A. Rice, author of The Encyclopedia of Evolution and Green Planet: How Plants Keep the Earth Alive, gives readers a rudimentary sketch of the present state of life on Earth with his latest title, Life of Earth: Portrait of a Beautiful, Middle-Aged, Stressed-Out World. In his depictions, Earth appears at turns fascinating, thorny, obstreperous, and sympathetic, but Rice's characterization of the planet as a whole serves an explicit agenda: to present his subject as an environmental victim.
Over the past decade, the most popular overviews of life on Earth have appeared as screen documentaries such as Disney's Earth (2007) and the British Broadcasting Company's Planet Earth (2006) and Life (2009). In contrast, Rice's overview is broader in scope. Life of Earth opens immodestly with an account of the origin of the universe, describing the origins of the geological and atmospheric circumstances in which it was possible for both photosynthesis and respiration to emerge. This story leads to a presentation of how evolution produced organisms with adaptations like altruism and religiosity. Rice uses this history to contextualize the current state of life, which he presents as being deeply threatened by human activity and political policy. His portrait of the planet fuels the cause of environmentalism, and what heft his conclusion has depends on readers' opinion of the book's epic, panoramic narrative.
Life of Earth assumes a broad perspective, with particular details of biology presented at a basic level. The science does not become much more complicated than this: “When one DNA molecule becomes two, the new strands are almost identical to the old ones,” Rice tells us. “Almost. Occasional mistakes occur during the copying process. These mistakes are called mutations” (p. 47). Clearly, the book is pitched to attract readers who have forgotten high school biology. Short segments of text, lasting no more than a few pages, are packed with intriguing facts written in the second person: “When animals began to live on land, they had to bring the ocean with them. To this day, the balance of salts in your cells is reminiscent of the saltiness of the ocean” (p. 83). Rice's natural-history observations are mixed with anecdotes about pop culture and the author's family. Life of Earth is not an academic book and is not particularly aimed at students, but it might be popular with those with no science background who want to be drawn in but not challenged by science. Rice aims to educate that audience with a heavy dose of light entertainment: “Dogs do this also. It's a wild and crazy time when the bitch is in heat” (p. 131), and “Back in the Stone Age, fat women were hot” (p. 123).
But a danger arises from this simple, jocular presentation of science: Ideas are occasionally simplified so much that they become misleading or confusing. For example, Rice defines evolution as natural selection (on p. 48): “The result is that the superior cells or organisms become more common than the inferior ones. This is natural selection: nature selects the superior mutations. That is what evolution is. That is all evolution is.” The author should have clarified that superiority of alleles is not absolute, but relative to context, and that processes other than natural selection play a role in evolution. I would not fault a reader for being confused eight pages later when reading that natural selection is a stabilizing force—“the kind of selection that prevents evolution from occurring” (p. 56). I imagine the reader wondering, “How could evolution, being selection, prevent itself?”
Covering a lot of biology quickly, Rice also asserts scientific positions that are not universally agreed on. He embraces the view of human thought popularized by Richard Dawkins, Daniel Dennett, and evolutionary psychology in general. Although that is no fault, the sort of reader first learning how evolution works will not have the perspective to distinguish whether Rice is presenting scientific consensus or merely advancing an angle: “Literature is memes… Science is memes… Everywhere you look there are memes, memes, and more memes, all of them evolving,” he writes, as though memes were a universally accepted part of standard biology (p. 70).
A tension between consensus science and individual perspective is most notable with the author's treatment of Gaia—Rice's framing device for the book itself. In his depiction, it is a female being who is stressed out by human activities. Gaia is an idea that “many scientists” share, Rice asserts. Following the approach of the late Lynn Margulis, to whom the book is dedicated, Rice treats Gaia as analogous to a person, while emphasizing that she is not a person. Like a person, she regulates not only herself but also her environment, within limits. She is depicted as having had an infancy and as expecting an old age—one that may not include us. We human beings depend on her; we are Gaia's children and also a part of her.
I suspect that some readers who are encountering the concept of Gaia for the first time will be drawn to how it frames a relationship between humans and a motherly nature. For those who find the Gaia imagery appealing, this book may be persuasive, but it will not suit everyone's taste. The Gaia concept aptly serves Rice's purpose for writing Life of Earth, however, by presenting the history of Earth on a human scale. Rice helps us to care for Earth's systems of photosynthesis and respiration and temperature regulation by treating them as analogous to human bodily functions. Yet Gaia's value lies in accomplishing what people cannot seem to do naturally: establishing and maintaining the conditions of life for our species and every other one. This is wondrous and also superhuman. But is it more impressive when anthropomorphized?
Although it is not a book for biologists or for classroom use, Life of Earth can be persuasive in its message. In helping readers comprehend the history of life on Earth, it reveals the indispensability of Earth's living systems, and through the central figure of Gaia, encourages us to care about them.