Beginning at the moment of creation with the Big Bang, Here on Earth explores the evolution of Earth from a galactic cloud of dust and gas to a planet with a metallic core and early signs of life within a billion years of being created. In a compelling narrative, Flannery describes the formation of the Earth’s crust and atmosphere, as well as the transformation of the planet’s oceans from toxic brews of metals (such as iron, copper, and lead) to life-sustaining bodies covering seventy percent of the planet’s surface.
Life, Flannery shows, first appeared in these oceans in the form of microscopic plants and bacteria, and these metals served as catalysts for the earliest biological processes known to exist. From this starting point, Flannery tells the fascinating story of the evolution of our own species, exploring several early human species—from the diminutive creatures (the famed hobbits) who lived in Africa around two million years ago to Homo erectus—before turning his attention to Homo sapiens. Drawing on Charles Darwin’s and Alfred Russel Wallace’s theories of evolution and Lovelock’s Gaia hypothesis, Here on Earth is a dazzling account of life on our planet.
“You’ll discover why Tim Flannery’s books have made him the rock star of modern science.” —Jared Diamond, Pulitzer Prize–winning author of Guns, Germs, and Steel
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Evolution's Motive Force
There is nothing conscious about life's lethal activities. Peter Ward 2009
Whatever each day held, Charles Darwin tried to set aside time for a stroll around a 'sand walk' near his home, Down House, in Kent. Tradition has it that the sand walk was his thinking space — the place where he sharpened his evolutionary theory, as well as the sentences that would so elegantly carry it into print. Consequently, the walk is regarded with reverence by many scientists, and when I made my first pilgrimage to Down House in October 2009 it was this place above all that I wished to see. After paying my respects to the great man's office and drawing room, I followed the signs to the walk. It's a little removed from the house and its enclosed gardens, and entering it one feels instantly transported from the ordered human world into the wider world of nature.
The walk consists of an oval-shaped path around a forest of hazel, privet and dogwood planted by Darwin himself. I was surprised to discover that despite its name there is no sand on it, nor has there ever been. Instead, it is surfaced with flints, which Darwin's son Francis remembered his father kicking from the path as a means of keeping count of the number of circuits he'd completed. The forest is now tall and venerable, and as I strolled I found myself pondering the thoughts that might possess a man as he walked repeatedly — almost compulsively — on a course as regular as a racetrack, through what must then have been saplings. While we can't know what occupied Darwin on the sand walk, there are hints in notes left by his children. As they grew up they took to playing in the walk, and often distracted and delighted their father with their games. To a man immersed in complex reasoning, such disturbances would surely be resented, so perhaps complex theories or elegant sentences weren't the things that occupied him after all.
It's my guess that during this repetitious physical activity Darwin was mentally fingering his worry beads — and looming large among his concerns were the implications of the theory he is now famous for. Known today as evolution by natural selection, it explains how species, including our own, are created. Natural selection, Darwin understood from his studies, is an unspeakably cruel and amoral process. He came to realise that he must eventually tell the world that we are spawned not from godly love, but evolutionary barbarity. What would the social implications be? As his discovery became widely understood, would faith, hope and charity perish? Would England's early industrial society, already barbaric enough, become a place where only the fittest survived, and where the survivors believed this was the natural order? Might his innocent-sounding theory turn people into cold-blooded survival machines?
Charles Robert Darwin was born in 1809 in Shropshire, the son of a wealthy society doctor. Baptised into the Anglican Church, he was expected to follow his father into medicine. But the cruelty of surgery in the pre-anaesthetic era horrified him, so he quit his studies in favour of training as an Anglican parson, and in 1828 he enrolled in a Bachelor of Arts degree at Cambridge. This was the necessary prerequisite for a specialised course in divinity, and in his finals he excelled in theology, while barely scraping through in mathematics, physics and the classics. Darwin's plans for a life of bucolic vicardom, however, were deferred when, in August 1831, he heard that a naturalist was needed for a two-year voyage to Tierra del Fuego and the East Indies aboard the survey ship Beagle.
Although his father initially opposed the venture, Charles won him over and was accepted as a self-funded gentleman naturalist on the voyage. His most important duty, from the navy's perspective, was to provide Captain Robert Fitzroy — a man of rather melancholy temperament — with companionship. The voyage would stretch to five years, taking Darwin round the globe and exposing him to the extraordinary biodiversity and geology of South America, Australia and many islands. It was in the Galápagos archipelago that Darwin collected what would become vital evidence for his theory — species of birds and reptiles that had evolved on, and were unique to, specific islands. For any young man such a voyage would be formative, but for Darwin it was world-changing. He later said that 'the voyage of the Beagle has been by far the most important event in my life and has determined my whole career'.
The experience led Darwin to reject religion. He later described how he had struggled to hold onto his faith, even as exposure to other cultures and the wider world made it less and less plausible:
I was very unwilling to give up my belief; I feel sure of this, for I can well remember often and often inventing daydreams of old letters between distinguished Romans, and manuscripts being discovered at Pompeii or elsewhere, which confirmed in the most striking manner all that was written in the Gospels. But I found it more and more difficult, with free scope given to my imagination, to invent evidence which would suffice to convince me. Thus disbelief crept over me at very slow rate, but was at last complete.
Upon returning to England in 1836, Darwin was accepted immediately into the bosom of the Victorian scientific establishment, and he commenced working up his Beagle discoveries. In 1842, aged thirty-two, he purchased Down House and there embarked upon a long career as an independent, and independently wealthy, scientist. The property provided for all Darwin's needs, serving as both a laboratory and a family home. Relatively modest in size, Down House must have been alive with the sounds of Charles and Emma Darwin's seven surviving children, and at times it must have seemed crowded. There is nonetheless an orderliness to the house and grounds that marks them as laboratories, in which Darwin pursued every conceivable ramification of the theory of evolution by natural selection, from the pollination of orchids to the origins of facial expressions.
Such a life is for the scientist a kind of Nirvana, but Darwin's lot was not entirely a happy one. Soon after returning from the Beagle voyage he fell ill, and for the rest of his life was plagued with symptoms, including heart palpitations, muscle spasms and nausea, that increased as he anticipated social occasions. Down House became his refuge, its solitude sustaining him through years of relentless work, illness and psychological stress until his death in 1882. I have little doubt that his illness was partly psychological, and exacerbated by what he believed to be the moral implications of his theory — a theory he largely kept to himself for twenty years. Darwin had realised that new species arose by natural selection as early as 1838, but he didn't publish until 1858. 'It is like confessing a murder,' he confided to a fellow scientist when explaining his evolutionary ideas in a letter.
Down House is central to Darwin and the development of his theory, and to understand that extraordinary place one can do no better than to read Darwin's study of earthworms. We might have earthworms in our gardens and compost bins, but few of us take the time to investigate them. For Darwin, however, they held a lifelong fascination. In many ways his worm monograph, which was his last book, is his most remarkable, documenting as it does experiments that ran continuously for almost three decades. Some of the worms lived in flowerpots, which were often kept inside Down House, and they seem to have become family pets. Certainly their individual personalities were appreciated, Darwin noting that some were timid and others brave, some neat and tidy while others were slovenly.
Eventually the entire Darwin family became involved in the worm experiments. I can picture Charles, surrounded by his children, playing the bassoon or piano to the worms in order to investigate their sense of hearing (they turned out to be entirely deaf), and testing their sense of smell (also alas rudimentary) by chewing tobacco and breathing on them, or introducing perfume into their pots. When Darwin realised that his worms disliked contact with cold, damp earth, he provided them with leaves with which to line their burrows, in the process discovering that they are expert practitioners of geometry (and indeed origami), for in order to drag and fold leaves efficiently, he noted, they must ascertain the shape of the leaf and grasp it appropriately. Darwin also provided his worms with glass beads, which they used to decorate their burrows in very pretty patterns. But, most importantly, he learned that worms profited from their experience, and that they were apt to be distracted from tasks by various stimuli he presented; and this, he believed, pointed to a surprising intelligence.
The sagacity and morality of worms were subjects Darwin never tired of. He concluded that wasps, and even fish such as pike, were far behind worms in their intelligence and ability to learn. Such conclusions, he said, 'will strike every one as very improbable', but:
It may be well to remember how perfect the sense of touch becomes in a man when born blind and deaf, as are worms. If worms have the power of acquiring some notion, however rude, of the shape of an object and of their burrows, as seems to be the case, they deserve to be called intelligent, for they then act in nearly the same manner as would a man under similar circumstances.
The worm monograph is also important in another way. In it Darwin came as close as he ever would to a sense of how Earth as a whole works. He had brushed against this subject in one of his early scientific papers that dealt with atmospheric dust he had collected while on the Beagle. Darwin thought that it was from the Sahara and was headed to South America, where the many spores and other living things included in it might perhaps find a new home. He never expanded his study into a theory of how dust might affect Earth overall, unlike more holistic thinkers we shall soon encounter who saw in dust important clues as to how life influences our atmosphere and climate. Darwin waited over half a lifetime before approaching what today is called Earth systems science — the holistic study of how our planet works — and, when he did so, it was through the lens provided by worms.
Darwin described how worms occur in great density over much of England, and how they emerge in their countless thousands in the darkest hours, their tails firmly hooked in their burrow entrances, to feel about for leaves, dead animals and other detritus which they drag into their burrows. Through their digging and recycling they enrich pastures and fields, and so enhance food production, thereby laying the foundation for English society. And in the process they slowly bury and preserve relics of an England long past. Darwin examined entire Roman villas buried by worms, along with ancient abbeys, monuments and stones, all of which would have been destroyed had they remained at the surface; and he accurately estimated the rate at which this process occurs: about half a centimetre per year.
Darwin's monograph on worms reveals much of the man's temperament, and of his particular sense of humour. But it also highlights his strengths as a scientist — an ordered mind and immense patience. But patience can be a weakness too, and in the end it almost robbed Darwin of his future fame, for his dilatory approach to publishing the theory saw him nearly trumped by a man twenty years his junior, an unknown naturalist working in far-off Indonesia named Alfred Russel Wallace.
On 18 June 1858, Darwin received a letter from Wallace outlining a theory that described the way in which new species come into existence, and asking Darwin to transmit the manuscript to Charles Lyell, one of England's most eminent scientists, for publication. Darwin was devastated. 'I never saw a more striking co-incidence. If Wallace had my MS sketch written out in 1842 he could not have made a better short abstract,' wailed Darwin to his friend Lyell. Only quick footwork by Lyell and another of Darwin's friends, the botanist Joseph Hooker, allowed Darwin's 'sketch' of 1842 and Wallace's paper to be published simultaneously by the Linnean Society of London on 1 July 1858.
As it was, neither Darwin's nor Wallace's paper attracted much immediate attention. In summarising the research published in the society's journal that year, President Thomas Bell was rather complimentary of the amount of botanical work completed, but lamented that the year 'had not, indeed, been marked by any of those striking discoveries which at once revolutionise, so to speak, the department of science on which they bear'. To make an impression on the public, clearly something more was needed, and this Darwin produced the following year. On 24 November 1859 his book On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life was published. It was an instant success, forever securing Darwin's supremacy as the great evolutionist.
Despite being largely ignored, Darwin's first effort at introducing his idea got to the heart of the matter. In his 1858 paper he wrote:
Can it be doubted, from the struggle each individual has to obtain subsistence, that any minute variation in structure, habits, or instincts, adapting that individual better to the new conditions, would tell upon its vigour and health? In the struggle it would have a better chance of surviving; and those of its offspring which inherited the variation, be it ever so slight, would also have a better chance. Yearly more are bred than can survive; the smallest grain in the balance, in the long run, must tell on which death shall fall, and which shall survive. Let this work of selection on the one hand, and death on the other, go on for a thousand generations, who will pretend to affirm that it would produce no effect?
The essence of Darwin's insight is thus very simple. More are born than can survive, and those best fitted to the circumstances into which they are born are most likely to survive and breed. This selection of individuals, generation after generation, over the vastness of geological time, causes descendants to differ from their ancestors. There is no morality in this argument — no overall superiority of one individual, class or nation over another — for as the environment changes so do those selected as the 'fittest'. But it did reveal a terrible truth — the weak (poorly adapted) must die if evolution is to progress.
On that day in 1858 when his revolutionary idea was made known to the world, Darwin was unable to be with his assembled colleagues. He was instead mourning the death of his son, his namesake Charles. Always a frail child, Charles died of scarlet fever aged eighteen months. We can only imagine the mood in Down House that day. Infant death was far more common then, but not one whit less devastating. And the head of the family had just brilliantly elucidated the process that had rendered his child nothing but a cooling pile of flesh, food for worms. For Darwin, who believed that there was no hereafter and no God to comfort him in his grief, the blow must have been almost unbearable. And now he had to live with the thought that his theory might rob such comforts from the entire world.
It's hard to imagine, from today's perspective, the impact Darwin's book and theory had on society, but some sense of it can be gained from a debate held in Oxford's stately Zoology Museum in 1860. Arguing on Darwin's behalf was zoologist Thomas Huxley, later known as Darwin's bulldog, and opposing him was Samuel Wilberforce, the Bishop of Oxford, known as Soapy Sam on account of being one of the finest public speakers of his day. On the Origin of Species had been published just seven months earlier, splitting church and society. About a thousand people crowded between the skeletons, stuffed animals and mineral specimens to hear the bishop and the scientist slug it out. Hundreds more were turned away for lack of room, and Darwin, fast becoming a perpetual valetudinarian, was absent.
The critical moment came when Wilberforce took a cheap shot, asking whether Huxley was descended from an ape on his mother's or his father's side. This prompted an extraordinary response, which Alfred Newton, an eye-witness, described as follows:
This gave Huxley the opportunity of saying that he would sooner claim kindred with an Ape than with a man like the Bishop who made so ill a use of his wonderful speaking powers to try and burke, by a display of authority, a free discussion on what was, or was not, a matter of truth, and reminded him that on questions of physical science 'authority' had always been bowled out by investigation, as witness astronomy and geology.
He then got hold of the Bishop's assertions and showed how contrary they were to facts, and how he knew nothing about what he had been discoursing on.(Continues…)
Excerpted from "Here on Earth"
Copyright © 2010 Tim Flannery.
Excerpted by permission of Grove Atlantic, Inc..
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
SECTION 1 MOTHER NATURE OR MONSTER EARTH?,
CHAPTER 1 Evolution's Motive Force,
CHAPTER 2 Of Genes, Mnemes and Destruction,
CHAPTER 3 Evolution's Legacy,
CHAPTER 4 A Fresh Look at Earth,
CHAPTER 5 The Commonwealth of Virtue,
SECTION 2 A TUR BULENT YOUTH,
CHAPTER 6 Man the Disrupter,
CHAPTER 7 New Worlds,
CHAPTER 8 Biophilia,
SECTION 3 EVER SINCE AGRICULTURE,
CHAPTER 9 Superorganisms,
CHAPTER 10 Superorganismic Glue,
CHAPTER 11 Ascent of the Ultimate Superorganism,
SECTION 4 TOXIC CLIMAX?,
CHAPTER 12 War against Nature,
CHAPTER 13 Gaia-killers,
CHAPTER 14 The Eleventh Hour?,
CHAPTER 15 Undoing the Work of Ages,
SECTION 5OUR PRESENT STATE,
CHAPTER 16 The Stars of Heaven,
CHAPTER 17 Discounting the Future,
CHAPTER 18 Greed and the Market,
CHAPTER 19 Of War and Inequality,
CHAPTER 20 A New Tool Kit,
CHAPTER 21 Governance,
CHAPTER 22 Restoring the Life-force,
SECTION 6 AN INTELLIGENT EARTH?,
CHAPTER 23 What Lies on the Other Side?,