Paradise lost

The Isle of Sheppey lies in the mouth of the Thames tucked up along the northern coastline of Kent, south-eastern England. Known to the Romans as insula orivum, and accessible for centuries only by ferry, the small Isle waited until 1860 for the construction of its first permanent bridge, over the River Swale to the mainland. It contains an uneasy mixture of lowland agricultural farmland, tourism, and commercial shipping activities, all divided by a diagonal east-to-west line of low hills. Elmley Marshes, situated on the southern side of the Isle, attract thousands of ducks, geese, and wading birds in the winter. Further to the east lies the Swale National Nature Reserve, a mosaic of grazing land and salt marshes that is home to short-eared owls and hen harriers. Fine beaches dotted along the northern coastline near to the traditional seaside town of Leysdown-on-Sea draw tourists whose spending boosts the local economy. Discovery of a deep-water channel off the north-west coast saw the construction of a Royal Navy dockyard at Sheerness in 1669. The new dockyard was replaced 290 years later by the commercially successful Port of Sheerness, which benefits from the capacity to accommodate large modern ships regardless of the tides. Geology and the sea have combined to shape the cultural and economic aspects of the Isle from its earliest days. In the early part of the nineteenth century, pyrite—iron sulfide—collected from the beaches and foreshore provided a source of green vitriol dye for the tanning and textiles industries. At around the same time, a small industry flourished excavating cement stones (septaria) for the manufacture of Parker’s (or Roman) cement. But the supply of septarian nodules on the beaches was soon exhausted and, with the emergence of more economic means of producing cement, the industry collapsed. The fleeting septaria industry mirrors the fleeting existence of Sheppey, for the Isle is shrinking fast as wave action erodes metres of its cliffs each year. Ultimately, in no more than a geological instant, the Isle of Sheppey and its inhabitants will be gone.

The flourishing forests of Antarctica

By arriving at the South Pole on 14 December 1911, the Norwegian explorer Roald Amundsen (1872–1928) reached his destination over a month ahead of the British effort led by Captain Robert Falcon Scott (1868–1912). As Scott’s party approached the South Pole on 17 January 1912, they were devastated to see from afar the Norwegian’s black flag. On arrival, they discovered the remains of his camp with ski and sledge tracks, and numerous dog footprints. Amundsen, it turned out, had used dogs and diversionary tactics to secure victory while the British team had man-hauled their sledges. These differences were not lost on The Times in London, which marked the achievement with muted praise, declaring it ‘not quite in accordance with the spirit of fair and open competition which hitherto marked Antarctic exploration’. Exhausted, Scott and his men spent time the following day making scientific observations around the Pole, erected ‘our poor slighted Union Jack’, and photographed themselves in front of it (Plate 11). Lieutenant Bowers took the picture by pulling a string to activate the shutter. It is perhaps the most well known, and at the same time the saddest picture, of the entire expedition—a poignant image of the doomed party, all of whom look utterly fed up as if somehow sensing the fate awaiting them. The cold weather, icy wind, and dismal circumstances led Scott to acerbically remark in his diary: ‘Great god! This is an awful place and terrible enough to have laboured to it without the reward of priority.’ By this time, the party had been hauling their sledges for weeks, and all the men were suffering from dehydration, owing to fatigue and altitude sickness from being on the Antarctic plateau that sits nearly 3000m above sea level. Three of them, Captain Oates, Seaman Evans, and Bowers, were badly afflicted with frostbitten noses and cheeks. Ahead lay the return leg, made all the more unbearable by the crippling psychological blow of knowing they had been second to the Pole. After a gruelling 21-day trek in bitterly cold summit winds, the team reached their first cache of food and fuel, covering the distance six days faster than it had taken them to do the leg in the other direction.

Introduction

Charles Darwin (1809–82), the greatest naturalist of all, was fascinated by them, Richard Dawkins all but ignored them. The world, it seems, is divided about the charms of the plant kingdom. The opening quotation of this chapter is from the American popular science author Tom Weller’s witty and provocative 1985 book Science made stupid, and sums up the malaise afflicting those on one side of the great divide. To these folk, plants have an unexceptional evolutionary trajectory leading up to the emergence of our modern floras and play no appreciable role in unravelling Earth’s history. Too often, this view is reiterated, reinforced, in Earth science textbooks, where it is palmed off on the unwary reader as received wisdom. Many such scholarly tomes devote a few pages to Earth’s first green spring, that decisive moment of our past when terrestrial plants turned the continents green. A few graciously give more space—an entire chapter, perhaps—to the progression of plants up the evolutionary ladder from their earliest beginnings through to the appearance of the first forests, the emergence of seed plants, and the blooming of the Earth with the rise of flowering plants. Fewer still recognize plants as important players in the game of life. In this book I argue that Weller’s viewpoint, and the conventional view of textbooks, is now outdated, redundant even, and misguided. The scientific investigation of fossil plants is on the threshold of an exciting new era, a grand synthesis illuminating new chapters in the inseparable stories of plant evolution and Earth’s environmental history. This book is about that new science. It is an endeavour that has emerged unnoticed in the last two decades but which is proving a powerful tool for clearing a path through the dense, sterile thicket of entrenched orthodoxy. It advocates fossils not as the disarticulated remains of ancient plant life gathering dust deep within the basements of museums, but as exciting, dynamic entities brought to life in new ways by the scientific investigation of their living counterparts. The Emerald planet is not a textbook, nor an attempt at describing, blow-by-blow, the detailed evolutionary history of plant life over the ages in a manner accessible to the general reader.

Through a glass darkly

Throughout this book we have encountered a varied cast of historical characters, who have pioneered the development of palaeobotanical thought over the past two centuries. Although the fascination of plant fossils has an exceptional pedigree, reaching back to at least the eleventh century, Edward Jacob (Chapter 7) was the earliest of these ‘searchers of scientific truth’ introduced here. Jacob’s eighteenth-century claim to fame lay in his descriptions of the fossilized remains of exotic subtropical floras and faunas in the crumbling sediments around the coastline of the Isle of Sheppey. Jacob was followed by the true palaeobotanical pioneers of the eighteenth and nineteenth centuries, who established the scientific basis for the anatomical and microscopic investigation of fossil plants. Through their synthesis of palaeontological knowledge, they established the study of fossils as technical and exacting, rather than a mere hobby. And a common thread linking us with this ‘golden age’ of discovery and description is the notion that the fossils record some aspects of Earth’s ancient climates. It’s a telling reminder that curiosity compels us to ask why certain fossils are where they are and to speculate on what it means. Albert Seward, who examined Scott of the Antarctic’s fossils (Chapter 6), codified this concept best with his celebrated and timely 1892 essay. Seward’s essay opened the eyes of devotees of fossil plants to possibilities beyond the traditional activities of description and classification. The argument of this book is that the emerging modern synthesis sees the dawning of a new era in the study of fossil plants. I am advocating that this modern synthesis arises out of the seamless integration of new knowledge concerning the physiological and ecological behaviour of living plants and ecosystems into the subject of palaeobotany. The promise of incorporating a powerful and exciting third strand, the science of the genetic pathways controlling the form of organisms—evolutionary developmental biology—into our thinking, is on the horizon. If this view is correct, then the study of living plants may be the driving force for unlocking greater riches from fossilized plant remains.

An ancient ozone catastrophe?

The University of Cambridge is one of the oldest seats of learning in the world and is, as befits such an august institution, steeped in tradition and history. One of the more curious traditions, which survived until 1909, was that of publicly ranking undergraduates who had taken the Mathematical Tripos, the oldest and most demanding examination of its kind. Candidates concluded 10 (now 9) semesters of intensive study by sitting a gruelling series of eight lengthy papers, each more difficult than the last, undertaken over a period of nine days. In rank order, the first 30–40 were called wranglers; the man gaining the highest marks of the year held the enviable position of Senior Wrangler. By tradition the positions were published in the London Times, with the accompanying list carrying pictures and short biographies of the top finishers; being a wrangler conveyed a certain degree of national honour and university distinction. Competition to become Senior Wrangler was intense. The examinations involved a test of knowledge, power of recall, concentration, and nerves, and a system of private coaching developed in response to the demands among the elite mathematicians to be Senior Wrangler. Coaches were often those who had previously placed well in the wrangler competition, with good ones able to teach essential mathematics and an ability to produce stock answers concisely so that as many problems as possible could be solved in the time available. The wrangler system evolved its own natural life cycle, ensuring its perpetuity, for a good coach could charge a tidy sum for seeing a student twice weekly over a year and usually had several candidates on his books. A certain William Hopkins was a superlative tutor who had, by 1849, coached 17 Senior Wranglers and 44 top three places. Wranglers in the top few places had the opportunity to take up a pleasant college fellowship or work as a coach fashioning a career to produce more wranglers. Women in the days of Victorian and Edwardian Cambridge were not awarded a degree but were, from 1870 onwards, permitted to sit the Tripos examination.

Oxygen and the lost world of giants

Oxygen, in its molecular form, is the second most abundant gas in our atmosphere but second to none in courting controversy. Its discovery is often credited to the great experimenter Joseph Priestley (1733–1904), who in 1774 showed that heating red calyx of mercury (mercuric oxide) in a glass vessel by focusing sunlight with a hand lens produced a colourless, tasteless, odourless gas. Mice placed in vessels of the new ‘air’ lived longer than normal and candles burned brighter than usual. As Priestley noted in 1775, ‘on the 8th of this month I procured a mouse, and put it into a glass vessel containing two ounce measures of the air from my mercuric calcinations. Had it been common air, a full-grown mouse, as this was, would have lived in it about quarter of an hour. In this air, however, my mouse lived a full half hour.’ Later experiments revealed that mice actually lived about five times longer in the ‘new air’ than normal air, giving Priestley an early indication that air is about 20% oxygen. About the same time, the Swedish chemist Carl Scheele (1742–86), working in Uppsala, showed that air contained a mixture of two gases, one promoting burning (oxygen) and one retarding it (nitrogen). Like Priestley, Scheele had prepared samples of the gas that encouraged burning (‘fire air’) by heating mercuric oxide, and also by reacting nitric acid with potash and distilling the residue with sulfuric acid. However, by the time his findings were published in a book entitled the Chemical treatise on air and fire in 1777, news of Priestley’s discovery had already spread throughout Europe and the great English chemist lay claim to priority. Only later did it become clear from surviving notes and records that Scheele had beaten Priestley to it, producing oxygen at least two years earlier. The harsh lesson from history, which still rings true today, is that capitalizing on a new exciting discovery requires its expedient communication to your peers. The talented Scheele died at 43, his life shortened by working for much of the time with deadly poisons like gaseous hydrogen cyanide in poorly ventilated conditions.

Leaves, genes, and greenhouse gases

The Galileo spacecraft, named after the Italian astronomer Galileo Galilei (1564–1642), who launched modern astronomy with his observations of the heavens in 1610, plunged to oblivion in Jupiter’s crushing atmosphere on 21 September 2003. Launched in 1989, it left behind a historic legacy that changed the way we view the solar system. Galileo’s mission was to study the planetary giant Jupiter and its satellites, four of which Galileo himself observed, to his surprise, moving as ‘stars’ around the planet from his garden in Pardu, Italy. En route, the spacecraft captured the first close-up images of an asteroid (Gaspra) and made direct observations of fragments of the comet Shoemaker–Levy 9 smashing into Jupiter. Most remarkable of all were the startling images of icebergs on the surface of Europa beamed backed in April 1997, after nearly eight years of solar system exploration. Icebergs suggested the existence of an extraterrestrial ocean, liquid water. To the rapt attention of the world’s press, NASA’s mission scientists commented that liquid water plus organic compounds already present on Europa, gave you ‘life within a billion years’. Whether this is the case is a moot point; water is essential for life on Earth as we know it, but this is no guarantee it is needed for life elsewhere in the Universe. Oceans may also exist beneath the barren rocky crusts of two other Galilean satellites, Callisto and Ganymede. Callisto and Ganymede probably maintain a liquid ocean thanks to the heat produced by natural radioactivity of their rocky interiors. Europa, though, lies much closer to Jupiter, and any liquid water could be maintained by heating due to gravitational forces that stretch and squeeze the planet in much the same way as Earth’s moon influences our tides. To reach Jupiter, Galileo required two slingshots (gravitational assists) around Earth and Venus. Gravitational assists accelerate the speed and adjust the trajectory of the spacecraft without it expending fuel. The planets doing the assisting pay the price with an imperceptible slowing in their speed of rotation. In Galileo’s case, the procedure fortuitously permitted close observations of Earth from space, allowing a control experiment in the search for extraterrestrial life, never before attempted.

Nature’s green revolution

The scientific revolution of the seventeenth and eighteenth centuries, if indeed it can be recognized as such, saw the foundations of modern science established. Developments by iconic figures, notably Francis Bacon (1561–1626), Galilei Galileo (1564–1642), Robert Boyle (1627–91), and Isaac Newton (1642–1727), among others, advanced the study of the natural world by moving it away from mystical concepts and grounding it firmly in the rational. Bacon outraged his intellectual contemporaries with the belief that scientific knowledge should be built on empirical observation and experimentation, and pursuing this theme is alleged to have done for him in the end, at the age of 65. According to Bacon’s former secretary, the legend goes that Bacon was travelling in a coach towards London with one of the King’s physicians on a snowy day in April 1626 when he decided to investigate whether meat could be preserved by ice. Seizing the opportunity for an experiment, Bacon purchased a chicken in Highgate, then a small village outside London, gutted it, and proceeded to stuff the carcass with snow to see if it delayed putrefaction. In his excitement he became oblivious to the cold, caught a chill, and took refuge in the Earl of Arundel’s nearby house in Highgate, the Earl being away serving time in the Tower of London. Bacon died a few days later, probably from pneumonia, after being put up in a guest room with a damp bed disused for over a year, but not before penning a letter to the Earl communicating the success of the experiment. This delightful story of Bacon’s ultimate demise would have been fitting for his contribution to modern science, but is probably apocryphal. Surviving records indicate Bacon was already ill before the end of 1625, and inclined to inhale opiates and the vapours of chemical saltpetre (potassium nitrate) to improve his spirits and strengthen his ageing body. In those days, the saltpetre was impure, a mixture of potassium nitrate, sodium nitrate, and other compounds that may have given off toxic vapours. It seems possible, likely even, that Bacon overdosed on his inhalation of remedial substances to compensate for his ill health.

Global warming ushers in the dinosaur era

Reverend William Buckland (1784–1856), a British vicar and palaeontologist, was the first Professor of Geology at the University of Oxford (1813) (see Plate 8). Charming and eloquent, Buckland was also an accomplished lecturer. His biographer summed him up rather well, remarking in 1894 ‘it is impossible to convey to the mind of any one who had never heard Dr. Buckland speak, the inimitable effect of that union of the most playful fancy with the most profound reflections which so eminently characterized his scientific oratory’. Brilliant and famously eccentric, he once offended stuffier colleagues at a British Association meeting in Bristol by strutting around the lecture theatre imitating chickens to demonstrate how prehistoric birds could have left footprints in the mud. On another occasion he: . . . attracted an audience totalling several thousand for a lecture in the famous Dudley Caverns, specially illuminated for the purpose. Carried away by the general magnificence, he was tempted into rounding off with a shameless appeal to the audience’s patriotism. The great mineral wealth lying around on every hand, he proclaimed, was no mere accident of nature; it showed rather, the express intention of Providence that the inhabitants of Britain should become, by this gift, the richest and most powerful nation on Earth. And with these words, the great crowd, with Buckland at its head, returned towards the light of day thundering out, with one accord, ‘God save the Queen!’. . . Buckland also claimed to have eaten his way straight through the animal kingdom as he studied it and, allegedly, part of Louis XIV’s embalmed heart, pinched from the snuffbox of his friend the Archbishop of Canterbury. He was aided in the eccentric culinary consumption of animals by his son Francis Buckland (1826–80), the celebrated Victorian naturalist and one-time Inspector of Her Majesty’s Salmon Fisheries, who evidently inherited his father’s eccentricity. Francis Buckland lived amongst beer-swilling monkeys, rats, and hares and regarded firing benzene at cockroaches through syringes as a fine sport. Francis arranged with London Zoo to receive off-cuts from the carcasses of unfortunate animals.