Non-Fiction Reviews


Oxygen
The molecule that made the world

(2002 / 2016) Nick Lane, Oxford University Press, 9.99 / US$19.95, pbk, x + 374pp, ISBN 978-0-198-7849-3

 

This is actually quite an important book and not just your average history of science approach to oxygen's discovery; the latter only forms the substance of the book's first, introductory chapter. Actually this book is largely about how life evolved from bacteria to multicelled species (like you and me), as well as the tension between the benefits arising from the latter oxygen-fuelled complex life and the oxidative problem of ageing.

For me it is this former oxygen's role in species' evolution that is the most interesting, though if you are into nutrition and all the recent talk of anti-oxidant (so-called) superfoods, the book's latter chapters may be the ones you find more engaging.  Now, I know I should not second-guess this site's regulars' tastes, but as SF² Concatenation's regulars are largely qualified scientists who are also into science fiction, I suspect many will share my take that it is the grand evolutionary aspects that are the most thought provoking since they have combined with some Earth system science knowledge clear applications for the potentials, hence possibilities, for life on other worlds.  But I am getting ahead of myself.

Lane's story begins with the aforementioned introductory chapter covering the history of oxygen's discovery and early uses.  Personally speaking I find such basic, introductory chapters underappreciated. I was aware of Antoine Lavoisier being credited with the discovery of oxygen from my school chemistry class days, but was unaware of the role Sweden's Carle Scheele and Britain's Joseph Priestley and, though I was knew of the latter being loosely involved, clearly I did the man a disservice.  The chapter also contains other fascinating nuggets such as an early working submarine in 1621 that relied on bottled oxygen to sustain the crew. But it is the next few chapters in which the book's principal narrative really takes off.

In a nutshell, the first few chapters tells the story across the aeons of both the biosphere's oxygen and carbon, as well as their interaction through life: we are carbon-based life forms.  Next we get the evolution of oxygenic photosynthesis and the connection with Snowball Earth I. This connection is not spelled out in such a detailed way as I would like but then we have to remember that this book was first written in 2002 and the new, Earth System Science derived narrative of life's evolution on our planet is only now (second decade of the 21st century) being developed and firmly based on research that largely covers the past quarter century or so.

Nick Lane then goes on to make a convincing case as to how it was that the evolution of oxygen helped with the development of multicellularity from formerly only single-celled species.

Mid-book, the author returns to oxygenic photosynthesis.  Here he draws attention to the molecular similarities of some of the key molecules involved and those such as catalase that deal with hydrogen peroxide are similar to a macromolecule involved in the oxygen-evolving complex in oxygen-generating photosynthesis such as that used by modern plants.  He then goes on to show how hydrogen peroxide could have been present in a largely anaerobic Earth well before the initial rise of oxygen to a couple of a per cent atmospheric composition two billion years ago.

Mid-book, Nick Lane notes the striking resemblance of the gene that codes for cytochrome oxidase that is fundamental to the final step in final step in aerobic respiration, in many anaerobic bacteria.  This then begs the question as to what anaerobes were doing with mechanisms that transfer electrons to oxygen before the rise of oxygen in the atmosphere?  The answer the author suggests could be in the need for early life to deal with a UV drenched surface ocean as the early Earth (with next to no atmospheric oxygen) would have no UV protective ozone layer as we do today.  This UV would have produced oxidising (electron grabbing) free radicals and so would need so reducing (electron giving) mechanisms, hence a protein similar to cytochrome oxidase would confer a distinct evolutionary advantage if the Earth surface were to be colonised and the bounty of solar energy harnessed.

Looked at this way, with the catalase and cytochrome oxidase stories, it seems that given comparatively stable situations global elemental cycling (constant nutrients), ample liquid water (a decent chemical conveying solute) and solar energy that complex, multicellular life (including animals) was not just likely but almost impossible to avoid even if it took nearly 4 billion years of the Earth's history to get there. While Nick Lane does not ram home this message, it is nonetheless the clear implication given the steps the author lays out.

Yet oxygen is a highly reactive element: which is why life finds it such a good chemical with which to burn fuel (food) for energy.  Yet, the problem with highly reactive chemicals is that that they tend to react with things that you many not want them to react and so can, and do, pose a danger for cells. Hence the need for antioxidants.  The later chapters covers these aspects.  Along the way a number of engaging avenues are explored including a couple that are somewhat speculative.  Among these is the notion that we humans may possibly be selecting for longevity.  Here, Nick Lane's argument which he fully admits is a bit of fun kite flying is this: humans live twice as long as gorillas or chimpanzees but take a third longer to reach sexual maturity. Humans defer maturity to later by slowing the rate of development to adulthood. In the west we are now deferring having children to later in life. Could this 'slowing' possibly provide an evolutionary pressure for longevity? Your guess is as good as mine, but it is a fun notion.

And before you know it we are at the book's end as the last 32 pages are made up of reference notes, glossary and a solid index.

So to whom will this book appeal?  Well, first up I'd venture that a reader needs at least to have one A-level (a British school qualification gained before university at around 18 years of age) in science: this is not an arty-farty read.  But given that a significant proportion (a fifth or more) of the British population under 50 is so qualified this is not a big impediment for many to enjoy this remarkable text.  If you are seriously into exobiology and the likelihood of Earth-like life evolving on other worlds then I would recommend this book in combination with Revolutions that made the Earth (by Lenton and Watson and also from Oxford U. Press). Both books do necessitate a good school level grounding in science and are far more rewarding and informative than many of the astronomical and exoplanet perspective books supposedly on life on other worlds that currently abound. (In fact, I would go further: if you are professionally involved in exobiology these two books are an absolute necessity.)

Secondly, this book would be an ideal gap summer read for any school leaver who will be going on to read for a degree in biology, geology (Earth systems) and broadly related spin-out subjects from these two (such as medicine or palaeontology).

This book is part of Oxford University Press' 'Landmark Science' series that is marketed as 'revised'.  This last is the only disingenuous thing about this otherwise remarkable book, as the text does not seem revised at all other than have a new cover: the references are all pre-2001 and there is no recent science at all. Had there been then surely some of the science in the aforementioned Revolutions that made the Earth would have spilled into a revised text.  OK, so this flaw is an Oxford University Press marketing failure (surprising given this university press' stature) and not the author's: this text remains a remarkable one.  If you are in one of the previously mentioned reader groups then you will find this an extremely valuable as well as an engaging read.  Thoroughly recommended.

Jonathan Cowie


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