Life Ascending

A new book outlines the ten great inventions of evolution

By | May 21, 2009

How did we come to be here, conscious animals on a planet bursting with life? There's a long story and a short one. The long story is our planet's history, a 4.5 billion year epic of unimaginable complexity that defies being told in a single book. Then there's the short story, the story of the few seminal "inventions" of evolution from which everything else flowed. I outline this story in my new book, linkurl:__Life Ascending: The Ten Great Inventions of Evolution__.;http://www.amazon.co.uk/Life-Ascending-Great-Inventions-Evolution/dp/1861978480 Of course anyone can choose their own list of life's great inventions, and my list is personal, however well I may justify it. Nonetheless, each of these inventions transfigured the world, ultimately making our own existence possible. Here's the short story. 1. The Origin of Life
A 30-metre tall active alkaline vent.
Reproduced with permission from
Deborah S. Kelley and the Oceanography
Society
The origin of life is one of biology's biggest conundrums. How prebiotic chemistry gave rise to biochemistry, how the first cells formed, what kind of energy first powered metabolism and replication -- all these questions are serious challenges. Remarkably, all are answered in broad brush stroke by the amazing properties of alkaline hydrothermal vents, which form naturally chemiosmotic, self-replicating mineral cells with catalytic walls. They concentrate organics, including nucleotides, in impressive quantities, making them the ideal hatcheries for life. 2. DNA DNA is unique. RNA, chemically very similar, is far more unstable and reactive and couldn't encode organisms much more complex than a virus. For life to get going, DNA was needed. How a primordial RNA world gave rise to DNA and proteins is one of the great questions in biology. Yet a "code within the codons" gives suggestive clues to the origin of DNA and also points to life's origin in alkaline hydrothermal vents. A deep distinction in DNA replication mechanisms and other traits imply that bacteria and archaea emerged independently from a common ancestor in the vents. 3. Photosynthesis Without photosynthesis life couldn't get very far. Photosynthesis provides both the fuel and oxygen for respiration -- and only aerobic respiration generates enough energy to support multicellular life. Oxygenic photosynthesis arose just once in the history of evolution, in cyanobacteria. The trick demands an elaborate biochemical scheme to extract electrons from water and thrust them onto carbon dioxide. Without that improbable pathway, we would not be here. 4. The Complex Cell
Living stromatolites, constructed by
cyanobacteria.

Image: Courtesy of Catherine Colas des
Francs-Small University,
Western Australia.
All complex life on Earth is composed of nucleated cells, known as eukaryotic cells. The eukaryote arose only once, and bacteria normally show no tendency towards morphological complexity. The last common ancestor of eukaryotic cells was a chimera, formed in a unique union between two prokaryotic cells called endosymbiosis -- a non-Darwinian mechanism whereby organisms converge rather than diverge. Without that chimera, evolution may never have progressed beyond bacteria, and again none of us would be here. 5. Sex Sex is absurd. It costs a small fortune to find a partner, transmits foul venereal diseases and parasitic genes, and randomises successful allele combinations. Worse, sex requires males, viewed by implacable feminists and evolutionists alike as a waste of space. Why we all have sex anyway was seen as the queen of evolutionary problems in the 20th century. Recent work shows that over time all complex species would degenerate like the Y chromosome without sex. The details help explain why sex first arose, enabling early eukaryotes to thrive. 6. Movement Muscles set animals apart. They power grazing and predation and make food webs a reality. The proteins responsible for contractility -- actin and myosin -- are ubiquitous in eukaryotes and even in bacteria, propelling amoebae around, supporting plant cells, and helping bacteria divide. Actin forms dynamic cross links in much the same way that variant haemoglobin distorts red cells in sickle-cell anaemia. Selection fashioned such spontaneous quirks into the might of muscle. 7. Sight
A fruit fly's eye
Image: Courtesy of Walter
Gehring, Biozentrum, University of Basel,
Switzerland.
Sight may well have been the driving force behind the Cambrian explosion, when the first animals leapt into the fossil record about 550 million years ago. Thanks to a series of surprises in molecular biology, we now know how eyes evolved in great detail. Lens proteins and crystals were recruited from an astonishing range of sources, from calcite to mitochondria to stress proteins, but the ubiquitous light-sensitive protein rhodopsin probably evolved in algae, where it is used to calibrate light levels in photosynthesis. 8. Hot Blood Endothermy drives a supercharged lifestyle, making our own 24/7 dynamism possible. Many small mammals eat as much in a day as a lizard does in a month. A big benefit is stamina, but there is no necessary connection between stamina and resting metabolic rate, and theropods like __Velociraptor__ may have had the best of both worlds. One driver for endothermy may have been diets rich in carbon but low in nitrogen, such as leaves. Herbivores gain enough nitrogen from leaves if they eat a lot and jettison the excess carbon. Endotherms cleverly burn it off, gaining stamina while subsisting on a lower quality diet. 9. Consciousness Consciousness is the most subversive evolutionary adaptation. It enabled us to transform the world -- but there are still deep uncertainties about what it actually is. We don't know yet how neurons firing in the brain can generate a feeling of anything: what, if anything, a feeling is in physical terms. This is what philosophers call the "hard problem," and some say answering it requires a radical overhaul of the laws of physics. The answer may lie in bees, which have complex neural reward systems -- they may not be truly conscious, but if they feel anything at all, they already possess the physiological rudiments of consciousness. 10. Death Without death, natural selection would count for nothing, and life could never have evolved at all. Without cell death, or apoptosis, multicellular organisms are not possible. The key to both is mitochondria. They generate reactive free radicals that slowly undermine health, but in the short term optimise respiration, enhancing fitness when young. The penalty for vigour in youth is decrepit old age. There's hope. Birds leak fewer free-radicals, and live longer than mammals, without losing their vigour. The anti-aging pill may not a myth. Are these the best ten evolutionary inventions? You might disagree, but each one on my list transformed our planet, overwriting previous revolutions with new layers of complexity. Each dominates our lives today, each is scientifically and culturally iconic, and each evolved by natural selection. While fascinating in their own right, together they tell the remarkable story of life on Earth. More dramatic, more compelling, more intricate than any creation myth, this story has the added advantage of being, to a first approximation, true. linkurl:__Life Ascending: The Ten Great Inventions of Evolution__,;http://www.profilebooks.com/title.php?titleissue_id=574 by Nick Lane, Profile Books, London, 2009. 288 pp. ISBN: 978-1-861-97848-6. £18.99. linkurl:Nick Lane;http://www.nick-lane.net/ is a biochemist and honorary reader at University College London. His previous books include __Oxygen__ and __Power, Sex, Suicide__, and he's been described by Nobel Laureate Frank Wilczek as "a writer who's not afraid to think big -- and think hard." Lane's current research is on the constraints imposed by chemiosmosis in the origin and evolution of the eukaryotic cell.
**__Related stories:__***linkurl:Tentacles test tenets of evolution;http://www.the-scientist.com/blog/display/55198/
[18th November 2008]*linkurl:Biology's Gift to a Complex World;http://www.the-scientist.com/article/display/54988/
[September 2008]*linkurl:Butterfly Eyes;http://www.the-scientist.com/article/display/53317/
[July 2007]

Comments

Avatar of: anonymous poster

anonymous poster

Posts: 2

May 22, 2009

why not list something that science has actually demonstrated like antibiotics or 2nd/3rd generation pesticides... rather than these grand claims and hand waving?
Avatar of: Frank Lovell

Frank Lovell

Posts: 1

May 22, 2009

I read this article and think: What an awesome world Nature has created!\n \nThen I read the first anonymously posted comment above, and think: Ah, for cryin' inna two-tone bucket!\n\nYou can lead a horse to water,\nbut you can't make him drink;\nYou can lead an anti-evolutionist to evidence,\nbut you can't make him think!\n------------------------ Burma-Shave\n
Avatar of: anonymous poster

anonymous poster

Posts: 2

May 22, 2009

Smell?
Avatar of: anonymous poster

anonymous poster

Posts: 18

May 22, 2009

What an awesome story indeed, and well written. It seems so petty though, to end it with a slap at creation beliefs. To be sure, our current paradigms make literal interpretations appear untenable. Why bother mocking them? They come from our common heritage and should be honored as such. They come from our ancestors' best attempts to do exactly what you are doing, only with very limited data. \n\nAs far as truth claims, even many non-beleivers, like Stephen jay Gould or Thomas Kuhn for example, might take exception to your claims. Truth claims change science into philosophy, so be careful not to declare your philosophy as the new dogma.\n\nOne minor question: When you say that each evolved by natural selection, are you contradicting what you said about endosymbiosis being a non-Darwinian mechanism?\nDH\n
Avatar of: David Corney

David Corney

Posts: 1

May 22, 2009

I'm disappointed that a biochemist at UCL thinks that the *origin* of life can be addressed by evolution. Is evolution not defined as the changing of organisms over time to adapt to their surroundings by natural selection? Abiogenesis is the study of how life originated.
Avatar of: Matthew Grossman

Matthew Grossman

Posts: 27

May 22, 2009

If you are going to make top ten lists for evolution, this is a pretty good one. I am sure the deeper explanations for Lane?s picks will be quite an interesting read.\n\nRegarding the last bit, I don?t see anything anticreationist in it, what I think Lane was saying was, isn?t this an amazing (and weird) story of how things really seem to have evolved. On the other hand for a strict creationist a book on evolution isn?t likely to sit well no matter what.\n\nBut the picks are well chosen, and given it is on the entirety of evolutionary time, I can?t see how an innovation like antibiotics carries the same weight. Possibly down the road our innovations will effect evolutionary changes as profound as these.\n
Avatar of: anonymous poster

anonymous poster

Posts: 42

May 22, 2009

Science is engaged in by humans.\n\nFaith is engaged in by humans.\n\nHumans are limited in their (our) capacity to measure and accumulate knowledge, to process with absolute rigor what we know, to distinguish between what we know for certainty as opposed to what we only rationalize into interpretations that fit the CURRENT POOL of our insufficient knowledge.\n\nNature may be complete, but the study of it is not. And science as a study, should not be mistaken for that which it studies. The study of a thing is not the thing itself. And if any would argue that he is qualified to speak for "science," then let him satisfy us all as to how he came about the entirety of all its secrets, and arrived at their perfect interpretation, and did so without any bias whatsoever. \n\nAnd if the student of God (or the true believer in Him) would have us believe he is knows all there is to know of Him, then let that person step up and speak for God.\n\nLet the rest of us listen with our whole mind and heart, while those two thrash out the details for us, so we can get on with studying what we waste time arguing about... out of ignorance.\n\nGp ahead, Nature's duly authorized spokesperson. \nGo ahead God's duly authorized spokesperson. \nI, at least, am all ears.\n\nHello? Are you there?\n\nI'm waiting. Aren't we all. Are we not willing and ready to listen to these two spokespersons who have complete and perfect knowledge and reason to offer, to set the record straight as to whether science needs God, or God needs science, or one exists to the exclusion of the other. \n\nGo ahead. Don't be shy. Speak up. And, by all means, begin by telling us your perfect credentials and the name of the "giver" of your\nauthority.\n\nIf you do not step up and take on the role of qualified spokesman for Nature or God, or both, then what say you offer your OPINIONS and your personal PREDILECTIONS and your own private, individual choices of ASSUMPTIONS for what they are... and avoid the PRETENSE of being qualified to paint the kettle black. \n\n
Avatar of: null null

null null

Posts: 18

May 22, 2009

This book is a must buy, but I suggest not everyone will agree with the author's selection, making the book all that more interesting. If there is a scale of sorts for these "inventions," one must suggest that on a scale of 100, the origin of life is somewhere in the 90-plus range with everything else packed into the les than 10; the difference between non-living and living must be considered that great. Despite my and I am sure others preferences, the invention of sex is likely over-rated within this discussion, if the question is life or non-life for comparisons. Organisms without separate sexs have done quite well as documented in the fossil record, perhaps 3.5-3.7 billion years quite well, and an abundance and distribution that is quite amazing. \n\nThere are other matters of interesting discussion worth tinkering with, but this does nothing that distracts from the importance of the book. Again, I suggest this is a must buy!\n\nDonald Wolberg\nSocorro, NM\n
Avatar of: Raymond Landry

Raymond Landry

Posts: 1

May 22, 2009

Great! All subjects very well summarized.
Avatar of: Mike Serfas

Mike Serfas

Posts: 35

May 22, 2009

It is surprising to see DNA listed as one of the key advances, when inventors tinkering with PNA, GNA, and TNA have suggested that many alternatives were possible. Because DNA suffers from a key vulnerability - the formation of thymine dimers in response to natural sunlight - it is possible that a better alternative exists that was overlooked by organisms unable to substantially redesign their genetic codes. Perhaps DNA is not one of evolution's greatest successes but one of its larger failures.\n\nInstead of DNA, I would nominate the "genetic code" - proteins and the ribosomes that make them - a single consistent mechanism to specify anything from keratin to mucus, chlorophyll to cobra venom. Though the existence of "prosthetic groups", SECIS elements, and NRPS demonstrate that standard protein synthesis also has its limitations, chemists are still hard pressed to rival it. Without this versatile but consistent method to translate genome into chemistry, horizontal gene transfer between prokaryotes or from endosymbionts to host cells might never have been possible, and even within a species sexual recombination might have been unreliable.\n
Avatar of: Frank Leavitt

Frank Leavitt

Posts: 9

May 23, 2009

Since this thread has four anonymous posts, I do not think it is inappropriate to post my objection to anonymity. Why does The Scientist allow it? If people fear to take personal responsibility for their ideas, there is something suspect about their ideas. I would understand anonymity if, for example, a scientist from a cruel, totalitarian country posted something which might be interpreted as critical of the regime. But in a scientific or philosophical (I would call the creationism-evolutionism poliemic\nphilosophical) anonymous posts should not be allowed.\nFrank (Yeruham) J Leavitt, PhD\nFaculty of Health Sciences\nBen Gurion University\nBeer Sheva, Israel
Avatar of: Curt Deckert

Curt Deckert

Posts: 1

May 24, 2009

Who is the designer of these 10 inventions?\nCould evolution get a patent on life?\nEvolution is a result of change of the kind of life not an original designer of life.
Avatar of: John Collins

John Collins

Posts: 37

May 27, 2009

A limited life span in combination with sexuality and physical separation of germ-line from somatic cells (the Weissman barrier) prevents long term accumulation of viruses and other parasites in the population since each generation is a blank slate (clean) an due to population variablity having a novel ability to resist disease. Perhaps this is more important than eliminating the older (degenerate) members of the group. Since there is a difference of over five orders of magnitude in life span, comparing different species, it is not obvious that in-built ageing, plays any role in a real environmental condition. \n\nApoptosis does of course have another role in remodelling tissue during embryogenesis, and defending against disobedient unregulated (cancerous) cell growth.
Avatar of: john toeppen

john toeppen

Posts: 52

May 27, 2009

\nI will leave it to God to speak for himself. I will leave it to the arrogant to speak for religions, purportedly, in the name of God. I will speak for myself, and I will share my opinions with other scientists to try to comprehend the nature of the ongoing creation of life. Many of us will embrace the principles of science to clarify our understandings and appreciation of the complex nature of the universe. This seems to be one of the better paths to developing a sound philosophy and a better world\n\nThe book?s points are good and reasonably comprehensive, but serve as a starting point for perspective and dialog. The alkaline vents are interesting. The convergence of cells for symbiosis is a well taken point, but is sort of like sex. Sex is clearly a high risk with a great long term payback. Vision is certainly a way for life to have extended its scope and complexity.\n\nThought provoking dialog is one of the best results from such writings.\n
Avatar of: simon waters

simon waters

Posts: 7

September 2, 2010

I object to the statement: "DNA is unique. RNA, chemically very similar, is far more unstable and reactive and couldn't encode organisms much more complex than a virus. For life to get going, DNA was needed." \n\nRNA is stable chemically: it's instability in the "modern" world (i.e. after the beginning of evolution) is a consequence of the evolution of RNA digesting proteins and RNA digesting RNAs, now ubiquitous.\n\nRNA appears to be capable of carrying out many catalytic activities and could have formed the basis of an early self-replicating RNA ecology. Or so I've heard
Avatar of: Nils Jansma

Nils Jansma

Posts: 19

October 29, 2010

By: Nils Jansma\n\nI think it should be obvious why some people would rather post anonymously-- they fear consequences, whether good or bad. They may be a very famous person and does not want their ?fame? to detract from their message. Who knows why people choose not to identify themselves and who cares. I, personally, would be much more fearful of self appointed censors who judge material not on its merits but on some personal desire to apparently silence challenges to their worldview. Now, that is just my opinion, which is probably not worth a whole lot. However, whether you know me or not, if the shoe fits wear it\n

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