Taking on ‘The Vital Question’ About Life

Tim Requarth in The New York Times:

How did rocks, air and water coalesce into the first living creatures on the primordial Earth? Why did complex life like animals and plants arise from a single ancestor only once in the history of our planet? Why two sexes and not three or four or 12? Why do we age and die? In “The Vital Question: Energy, Evolution, and the Origins of Complex Life,” Nick Lane sets out to answer these questions and many more with a novel suite of ideas about life’s emergence and evolution. Dr. Lane, a biochemist at University College London, argues that with just a few principles of physics, we can predict why life is the way it is — on Earth and in the rest of the cosmos. (Read an excerpt.) Dr. Lane’s previous book, “Life Ascending: The Ten Great Inventions of Evolution,” won the Royal Society Prize for Science Books, and he again proves an able guide through treacherous scientific terrain. He writes in lucid, accessible prose, and while the science may get dense, the reader will be rewarded with a strikingly unconventional view of biology.

Dr. Lane’s most surprising idea concerns how complex life arose. For most of Earth’s history, he notes, life was microbial: no trees, no mushrooms, no mammals. While microbes display astonishing biochemical diversity, thriving on anything from concrete to battery acid, they’ve never evolved into anything more complicated than a single cell. So what made the great blooming of biodiversity possible? Dr. Lane, building on ideas developed with the evolutionary biologist William Martin, traces its origins to a freak accident billions of years ago, when one microbe took up residence inside another. This event was not a branching of the evolutionary tree but a fusion with, he argues, profound consequences. The new tenant provided energy for its host, paying chemical rent in exchange for safe dwelling. With this additional income, the host cell could afford investments in more complex biological amenities. The pairing thrived, replicated and evolved. Today we call these inner microbes mitochondria; nearly every cell in our body has thousands of these energy factories. Dr. Lane and Dr. Martin have argued that because of mitochondria, complex cells have nearly 200,000 times as much energy per gene, setting the stage for larger genomes and unfettered evolution.

More here.