The Vital Question by Nick Lane
Nick Lane’s four books (Oxygen: The Molecule That Made The World; Power, Sex, Suicide: Mitochondria & The Meaning Of Life; Life Ascending: The Ten Great Inventions Of Evolution; and now The Vital Question: Why Is Life The Way It Is?) have deservedly won plaudits from scientific and lay readers alike. Lane is a biochemist with a particular interest in questions of the early evolution of life, how life is “powered” (the thousands of mitochondria in your every cell), and the nature of life’s use of oxygen over four billion years of evolutionary history. In his new book, this award-winning author asks the biggest question of all.
A certain amount of scientific understanding is required to read this book, but not a huge amount, and any scientifically literate reader should be able to follow it without difficulty. Lane begins by outlining what he calls “the black hole at the heart of biology,” which are the baffling, apparently contradictory characteristics of all eukaryotic life (a eukaryote is a cell with a nucleus containing DNA – bacteria, archaea et al are prokaryotes, ie lacking a nucleus and holding their DNA loose inside their cell). For instance, what is the meaning of some of the eukaryotic cell’s inner bodies (mitochondria, chloroplasts) having their own DNA? What is the reason for the existence of sexual reproduction and the universal appearance of only two sexes? Why do cells die? And, of course, the biggest question of all – how did life begin from mere chemistry, 4 billion years ago?
It is this latter question that Lane begins with. Having dealt with the deficiencies of some current theories, he builds up a scenario of warm, alkaline hydrothermal vents which create geological formations full of microscopically tiny pores. He then shows how these inorganic volumes, if in the presence of warm water (energy), carbon dioxide, hydrogen and naturally occurring catalysts – essentially compounds of iron and sulphur – can easily and inevitably create proton gradients across membranes. From these first principles all the later inventions of prokaryotic life can be deduced: the use of hydrogen/sodium antiporters (essentially chemical ion movers that actively work across phospholipid membranes); the use of lipid membranes; energy requirements, motion away from the pores, and so on.
Lane then goes on to build up another crucial part of his case. It has been observed that the eukaryotic cell has characteristics universally conserved across all life forms on Earth. That fact has certain consequences; there must have been a single, unbelievably rare instance of one prokaryotic cell – likely a bacterium – engulfing another – likely an archaea – to the mutual benefit of both, from which the whole panoply of eukaryotic cells evolved. He then goes on to detail all the consequences of this symbiosis, not least its extraordinary evolutionary instability in very early times, a fact with consequences to all life that we now know.
The latter chapters of the book draw on Lane’s earlier work, specifically the energetics and dynamics of mitochondria, the evolution of eukaryotic characteristics, the nature of oxygen, anti-oxidants and free radicals, and much more.
I don’t think “absolutely fascinating, and most likely ground-breaking” is too strong a summary of this book. Towards the end Lane discusses the ramifications of his theory for life in the universe, in a section that will appeal to all SF writers.
Highly recommended to all fascinated by life on Earth and its origins.