Book Review: The Next Species

The Next Species:The Future of Evolution in the Aftermath of Manby Michael TennesenSimon & Schuster, 2015It's a very reassuring feeling, settling in to read a book by a veteran science-popularizer. They've grown accomplished at the twofold task of a) simplifying huge amounts of complicated information without bowdlerizing it, and b) conveying the results to an audience that, at least in America where the book is published, is both scientifically uninformed and scientifically incurious, to use a couple of polite euphemisms. It's a tough skill-set, and it tends to produce mighty entertaining books.A perfect case-in-point: The Next Species: The Future of Evolution in the Aftermath of Man by veteran science-writer Michael Tennesen, who takes up nothing less than the task of telling the whole biography of life on Earth in just over 250 pages – and succeeds with a sunny aplomb that would be beyond the abilities of most actual professional scientists (the late, lamented Stephen Jay Gould and Carl Sagan excepted, of course).His specific subject is the fate of Homo sapiens in a rapidly-changing world, but in order to reach that subject, he has to present what his fellow first-rate science-writer Timothy Ferris has referred to as “the whole shebang.” We move from the birth of the universe to the death of first-generation stars to the birth of new stars, the birth of our star and solar system, the slow birth and maturation of life on Earth, and then finally the appearance of modern humans and their subsequent reshaping of the entire world … a reshaping, he gently points out, that's been entirely negative, and that carries a heavy mortgage:

Our species is not impervious to the harm we are raining down on the planet. If we keep progressing on all destructive tracks – overpopulation, disease, climate change, destruction of the forests, destruction of the soil, exhaustion of our natural resources – one of them will take us out. Or perhaps it will be the combination of all these factors. We'll go extinct. It's a natural process. Usually it proceeds a little slower. Two hundred thousand years, our current stay on earth, is a short life for a species.

The starkness of that line “We'll go extinct” is in many ways the bass note of The Next Species: mankind is living out the normal lifespan of a species on Earth. And that lifespan ends in extinction, which, as Tennesen is hardly the first writer to notice, lurks at every turn of terrestrial life:

Extinction in reality is a simple process. It happens when the death rate of a species exceeds the replacement rate of newborns. This will come for man in five hundred, five thousand, or fifty thousand years as current rates of overpopulation, disease, or all the possibilities listed above continue. Toss in nuclear war, an asteroid (a regular occurrence in our geological history), or a supervolcano (a major factor in the Permian and Cretaceous), and we're there much faster.

It's the fourth and final section of Tennesen's book that serves as the payoff for all his compressed and very enjoyable prep-work; its in these pages that our author turns his attention to the future – and not necessarily humanity's future. He writes about massive potential changes to the landscape of life, from the various schemes for “re-wilding” Western natural spaces with African megafauna (or, more fantastically, with genetically reconstituted variations of Pleistocene species) to the theories of writers like Gregory Cochran and Henry Harpending, in their book The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, in which the authors theorize on the ways modern humanity might be even now evolving into something post-Homo sapiens. The numerous times in Earth's history when the planet's entire biosphere was brought to the brink of total catastrophe don't seem to bother writers like Tennesen, who view life itself as being as close to a given on the planet as anything could be. Accidentally or not, such writers usually find themselves echoing Jeff Goldblum's portrayal of Ian Malcolm in the Jurassic Park movie, wondrously intoning that “Life … finds a way.” And our author enthusiastically joins in:

A mass extinction may have grave consequences for some species, ours included, but it will not stop life. In the form of plants, animals, birds, reptiles, fish, fungi, and bacteria, life will find a way to exist, and will eventually adapt to survive any conditions thrown at it by man, natural selection, or the universe. Evolution has proven for over the last three billion years to be unstoppable. Nature survives even in war zones. If you give nature space, it finds a way to persist.

But cliché or not, it's a key and fascinating point – a kind of article of faith, but a key and fascinating point. In terms of pursuing the idea of species that will supplant Homo sapiens, The Next Species is at its weakest … a bit of an awkward thing, it being the books putative subject. But in terms of mentally prepping the reader for the idea of that supplanting, Tennesen's book is as good-natured a hymnal as any stubbornly egotistical species could want.