Life Ascending: The Ten Great Inventions of Evolution, Nick Lane, W.W. Norton & Company, 2009
Reviewed by Wayne Mones, Nov. 27, 2009
Bereshit bara elohim et hashamayim v鈥檈t ha鈥檃retz. So begins the Hebrew bible. English translators who render it as In the beginning, god created the heavens and the earth, beg the question posed by the great medieval commentator, Rashi., who asked, in the beginning of what? When the universe was a singularity -- when everything was contained in a space smaller than the period at the end of this sentence -- there was no time, no space, no matter, no beginning. Rashi insisted that a more accurate understanding must be rendered as: In the beginning of god鈥檚 creating the heavens and the earth鈥. This makes our story a very different one because it demands that we understand creation not as a single act but rather as the beginning of a creative process 鈥 a chain reaction if you will -- which must continue to unfold until everything ceases.
Seeking life鈥檚 beginnings tees up Rashi鈥檚 question to mystic, philosopher, deep historian, scientist and poet -- the beginning of what? Regardless of our perspective, we must begin our inquiry with the origin of our universe because in those beginnings are the physical laws, constants, chemistry, and mystery which make life probable. Inherent in the beginning are the seeds of never-ending creative processes.
The Hebrew bible, much like the fossil record, was written without vowels or punctuation. Just as succeeding generations of commentators, textual analysts, and dreamers of sacred fantasy have filled in the mystic鈥檚 tale, so have the modern tools of deep ocean exploration, DNA analysis, and X-ray crystallography filled in the scientist鈥檚 tale. Nick Lane鈥檚 Life Ascending recounts the latest version of the still-being-edited story of life unfolding, using as a focus the origin of life and the 鈥渋nvention鈥 of DNA, photosynthesis, the complex cell, sex, movement, sight, hot blood, consciousness, and death which Lane cheekily refers to as 鈥渢he ten great inventions of evolution.鈥 Cheeky because one must be careful in associating 鈥渋nvention鈥 with evolution. Such an association tempts one to regard early forms of life as primitive 鈥 as a mere prelude to what followed. Lane warns, early on, that living things have always had better things to do than to wait around to become us. Each life is and always has been complete.
Naturally, Lane begins his tale in the beginning -- with the formation and subsequent coalescing of the universe and the earth into a system in which it was possible for organic and mineral molecules to colonize rocks in deep ocean vents to form proteins and then living cells. He then explains the chemistry which allowed life to escape its formative environment and the invention of the related processes of photosynthesis and respiration which have allowed life to flourish. Lane illuminates the inter-relationship of organic molecules and minerals in a way that seems to blur the distinction between animal and mineral. The story leads readers to an understanding of life鈥檚 beginnings and evolution as being a logical and probable outgrowth of our planet鈥檚 prevailing physical conditions. The book is, in the tradition of the best science writing, an ommateum (a compound vision) of the interconnectedness of everything in the world, as befits a poet who just happens to be extremely well-versed in physics, geology, and biochemistry. Lane tells a scientists tale in a way that adds to his reader鈥檚 sense of radical amazement.
In his chapter on the invention of sex Lane recounts several theories, one of which likens sex to the race of the Red Queen (of Lewis Carol鈥檚 Through the Looking Glass) who runs furiously to get nowhere. All free-living organisms are in a perpetual race with parasites whose ability to transform and adapt to hone in on one host or another would quickly overwhelm host species if they weren鈥檛 constantly changing. The competition between parasites and hosts provides the endlessly shifting backdrop needed for sex to offer a big selection advantage.
Sex helps because parasites evolve rapidly: they have short lifespans and heaving populations. It doesn鈥檛 take them long to adapt to their host at the most intimate molecular scale 鈥 protein to protein, gene to gene. Failure to do so costs them their life; success gives them the freedom to grow and replicate. If the host population is genetically identical, then the successful parasite has the run of the entire population and may well obliterate it. If the hosts vary among themselves, however, there is a chance, indeed a probability, that some individuals will have a rare genotype that happens to resist the parasite. They will thrive until the parasite is obliged to focus its attention on this new genotype or face extinction itself. And so it goes on, generation after generation, cycling genotype after genotype, forever running and getting nowhere, as the Red Queen herself.
Lane鈥檚 chapter on movement recounts the evolution and organization of motor proteins which make movement possible and goes on the describe the problem of determining the evolutionary relationship between kinesins and myosins 鈥 two types of motor proteins whose gene sequences show to be unrelated. The two proteins appeared to be a case of convergent evolution in which two unrelated types of protein became specialized for a similar task, as in the evolutionarily unrelated wings of bats and birds. Given the small toolbox shared by all species, an investigator is compelled to dig deeper to uncover the common ancestor of the two proteins. Lane describes the unraveling of this riddle through a technique called X-ray crystallography.
But then their three-dimensional structures were solved by crystallography, to an atomic level of resolution. Whereas a gene sequence gives a two-dimensional succession of letters 鈥 the libretto without the music 鈥 crystallography gives the three-dimensional topography of the protein 鈥 the full glorious opera. Wagner once remarked that the music must grow from the words in opera, that the words come first. But nobody remembers Wagner for his heady Teutonic sentiments alone: it is his music that has survived to delight later generations. Likewise the gene sequence is the Word in nature, but the real music of the proteins is hidden in their shapes, and it is the shapes that survive selection. Natural selection cares not a whit about gene sequences: it cares about function. And although genes specify function, it is very often by dictating the shape of the protein, through the rules of folding about which we still know little. As a result, various gene sequences can drift so far apart that they no longer bear any resemblance to each other, as in the case of myosins and kinesins. Yet the deeper music of the protein spheres is still there to be discerned by crystallography.
On the basis of crystallography, then, we know that myosins and kinesins did indeed share a common ancestor, despite having so little in common in gene sequence.
As we mark the one hundred and fiftieth anniversary of the publication of On The Origin of Species, evolution is still the most compelling and exciting idea in biology. From the development of consciousness onwards we have had an innate need to know who we are, where we come from, what is our place in the world, and whether there is meaning to any of it. Stephen Jay Gould , in an effort to foster dialog between scientists and religious people, offered a theory of Non-overlapping Magisteria which erects a philosophical wall between scientific and religious inquiry. Nick Lane is one of those writer/scientists who digs tunnels under the wall. Lane demonstrates that all lines of enlightened inquiry come together in the weft and warp of a grand tapestry unfolding a unified vision of the world. He recounts that just as form and function were invented by evolution, so was consciousness, which he defines as: the awareness of self embedded in the world 鈥 a rich autobiographical awareness that defines an individual in the context of society and culture and history, with hopes and fears for the future, all cloaked in the dense reflective symbolism of language 鈥 if this is consciousness, then of course mankind is unique. If we accept that science, philosophy, religion, and art have their separate paths of inquiry 鈥 that science is concerned with the mind, but must cede the investigation of the concept of man to others, the study of evolution dictates that there must be tunnels under the walls, that all lines of inquiry must talk to each other from time-to-time. Life Ascending is a challenging read which provides ample rewards for the determined reader. It is literate and witty and one of my favorite science books of the past few years.