Instant Expert | Evolution Part One evolution Part one Not so long ago, all species were thought to have been created by god. Then along came evolution

Illustrations by Raymond Beisinger

16 July 2016 | NewScientist | 35 Instant Expert | Evolution Part One The evolution revolution The story of how one of science’s greatest ideas came into being is both remarkable and riddled with myths. lifts the lid

volution is the most 19th century it was widely had been abruptly ended appreciate how radical the revolutionary concept in the understood that Earth could not by some great catastrophe. concept was initially. However, it E history of science. Nothing be a few thousand years old, but Another puzzle was the soon became almost universally else has more radically changed must be inconceivably ancient. discovery in Europe and America accepted in the scientific our understanding of the natural Earth was also found to have of gigantic fossilised animals. community, with one important world and ourselves. changed over time. Close study Where could creatures such as exception: the French naturalist The work of of rocks and fossils revealed a mammoths be living today? Jean-Baptiste Lamarck. showed, irrefutably, that complex history of different Perhaps their kind had died out? For Lamarck, these unfamiliar humans are just another animal ages. One layer of the geological This couldn’t be true, according fossil forms had not gone occupying a small branch on record might show lush tropical to traditional belief, since God extinct. Instead they had a vast tree of life. No divine vegetation populated with would not allow any of his changed, evolving into spark is needed to explain reptiles unlike any alive today. created species to perish. something else – although his our existence and traits. In the rock layers just above, yet Cuvier’s detailed research in view of this process was different But how exactly did Darwin another terrestrial world might anatomy established, once and to that later proposed by Darwin devise his theory of evolution? have existed with different for all, that creatures such as the (see “The view before Darwin”, What ideas did he build on? animals and plants. To explain mammoth were not the same as below). The mammoth, for Where does the naturalist Alfred this, in 1812 the great French anything alive today, and were example, could have evolved Russel Wallace, who proposed a anatomist Georges Cuvier put extinct. For us, extinction is such into the elephant. similar theory, fit in? And how forward the idea that each age a mundane fact that we cannot As the influential Cuvier did shocking was the idea to the with so many rivals, he used his Christian society of the time? reputation to demolish Lamarck. The story of the uncovering The view The result was that for the first of this great revelation has been few decades of the 19th century, retold countless times since before darwin not only Lamarck’s theory but the publication of Darwin’s On Lamarckism is mentioned in biology textbooks as shorthand for a any theory of evolution was the Origin of Species in 1859. In pre-Darwinian theory of evolution in which species were thought to evolve considered unscientific and the process, the assumptions via the inheritance of characteristics acquired during an organism’s absurd. Although Lamarck and guesses of one generation lifetime. According to this, the giraffe got its long neck by intentionally won a few converts, many more became accepted as fact by the stretching to reach the top of trees. This slightly stretched neck was accepted Cuvier’s view that a next – with some spawning then passed on to offspring, and so on. But this version of Lamarckism succession of eras of life had widespread myths. Perhaps the is a terrible caricature. The biologist Jean-Baptiste Lamarck did not come and gone. most fundamental of these is originate this idea – which many naturalists, including Darwin, But where did the new that thinkers had been striving continued to accept –and this was not the core of his theory. Instead, species that emerged after these for centuries to solve the mystery Lamarck’s central idea was that there is a tendency for life to progress up extinctions come from? The of the origin of species. They the scale of perfection according to a “complexifying force”. New species geologist Charles Lyell argued hadn’t, and indeed they couldn’t originated continuously via spontaneous generation (the appearance in his Principles of Geology, have – just as ancient Greek of life from inorganic matter) and could adapt to local circumstances published in the early 1830s, philosophers could not have through the inheritance of acquired characteristics. that slow processes had changed been searching for dark matter. Earth over time. Lyell’s picture Traditionally, people in was one of perpetual change. Christian Europe had believed As an environment gradually that the world was about transformed, the species that 6000 years old. This view was lived in it would become unsuited guided by interpolations from to it and die out, because there the Bible, which itself gave no was a limit to how much they k c date for creation. Gradually o could change to adapt. Just how such beliefs were modified utterst new species arose was left vague. by Christian thinkers based on Lyell’s work was of great new information about Earth, interest to Charles Darwin, a gleaned from the growth of young Cambridge graduate mining and the development who was appointed to join the

of geology. By the early LIBRARY/UIG/REX/Sh PICTURE DEA surveying voyage of HMS Beagle

36 | NewScientist | 16 July 2016 John van Wyhe is a historian of science at the National University of Singapore. He is the founder of Darwin Online (darwin-online.org.uk/), the largest and most complete collection of Darwin’s writings, and the author of 10 books on Darwin, Wallace and evolution

Route to a breakthrough

Erasmus Darwin, Charles’s grandfather, 1795 foreshadows Darwin when he writes: “Would it be too bold to imagine that all warm-blooded animals have arisen from one living filament… with the power of acquiring new parts”

The doom-mongering An Essay on the Principle 1798 of Population by Thomas Malthus warns of the dire consequences of unrestricted population growth. It is a key influence on Charles Darwin o t

k Pho French naturalist Jean-Baptiste Lamarck publishes c o t S 1809 Philosophie Zoologique, outlining his idea of lamy

/A evolution according to a “complexifying force” useum ry M

o Charles Robert Darwin is born in Shrewsbury, UK, 1809 the fifth of six children in a prosperous family atural Hist e N

Th French zoologist Georges Cuvier publishes Essay on 1813 the Theory of the Earth, setting out his idea that Galapagos Islands finches: were After the return of HMS new species appear after catastrophes such as floods they key to Darwin’s ideas? Beagle in 1836, Darwin set to work describing his mountain Alfred Russel Wallace is born in the village of as a naturalist in 1831 (contrary of specimens. He also began 1823 Llanbadoc near the border of England and Wales, to popular accounts, he was asking himself deep questions the seventh of nine children not invited along to be the about nature, life and religion. captain’s social companion, Gradually, he gave up his Darwin sets sail on HMS Beagle for a survey nor was the ship’s surgeon belief in Christianity. “It is 1831 of South America. The voyage lasts five years the official naturalist). During not supported by evidence”, this five-year voyage, Darwin he concluded. Nevertheless, Darwin sketches the first “tree of life” in his matured into one of the most as far as we know, he never 1837 notebook to explain the evolutionary relationships experienced scientists of his lost a belief in a supernatural between species generation. He worked primarily creator behind nature. as a geologist but also collected Several types of evidence led Wallace departs for an expedition to Brazil. On the a wide range of living things, Darwin to accept that species 1848 return journey four years later, a fire destroys many from finches to fungi. must evolve. On his voyage down of his specimens The expedition first visited the South American continent, South America, then surveyed he observed that related species Wallace conceives of his theory of how species adapt the waters around the Galapagos gradually replaced one another. 1858 to a changing world. On 1 July both Wallace’s and Islands. Only in the middle of The species living in the Darwin’s ideas are presented at the Linnean Society the 20th century did Darwin’s Galapagos also puzzled him. of London visit there come to be portrayed Many of these were unique to the as a pivotal moment in his life. islands, yet most were strikingly Darwin’s is published He never described it as such. similar to South American 1859 and becomes the object of much ridicule and abuse And as charming as it sounds, species. But the Galapagos, a there is no truth to the story collection of marine volcanoes, Debating evolution at Oxford, Bishop Samuel that Darwin noticed the beaks had never been connected to 1860 Wilberforce asks Thomas Huxley, a champion of of the finches were adapted to South America and their climate Darwin’s ideas, if Huxley’s monkey ancestors were different diets and that this was totally different. on his grandmother’s or grandfather’s side provoked his evolutionary According to Lyell’s view, theorising. There was no species were somehow created to Evolution comes to be accepted as fact by most of Galapagos eureka moment. suit new environments. So why 1870 the international scientific community

13 December16 July 20162014 | NewScientist | 37 Instant Expert | Evolution Part One

“The implication that human beings must have evolved from earlier species was objectionable to many”

weren’t the Galapagos species Darwin’s natural selection. were so obviously related to When he recovered, Wallace South American ones instead wrote an essay, “On the of just being rocky island tendency of varieties to depart species? Darwin’s explanation indefinitely from the original was that their ancestors must type”, aimed primarily at Lyell’s have come from South America anti-evolutionary arguments. and changed over time. Shortly after, Wallace received an In 1838, Darwin read Thomas encouraging letter from Darwin Malthus’s 1798 An Essay on stating that Wallace’s hero, Lyell, the Principle of Population, admired Wallace’s work. This which argued that continued led Wallace to send the essay to population growth would lead to Darwin with the request that famine and starvation. Darwin it be forwarded to Lyell. was struck by the implications It has been claimed that of checks to population growth. Darwin might have lied about This led him to focus on what when he received the essay, allowed some individuals rather leading to accusations that than others to survive and pass Darwin could have plagiarised on their characteristics. Wallace. In fact, Darwin He hypothesised that every received the essay exactly organism varied in many small Yet there is not a shred of the lower-class underdog to the when he said he did. ways, and any of these variations evidence for either suggestion. genteel, moneyed Darwin. But Darwin was struck by the that helped or hindered would In fact, Darwin told his family, Wallace was not working class, resemblance between Wallace’s make a difference to which friends and colleagues about his and neither was he forced to views and his own. The same day, survived. He eventually called theory and his plans to publish leave school early because of Darwin sent the essay on to Lyell, this filtering process “natural it. He felt he had years of his family’s finances. He was bemoaning that he ought to send selection” by analogy with research to conduct before he not deprived of his proper share it for publication ahead of his the process in which farmers would be ready and, like his of credit or made the victim of own work. For someone who changed domesticated plants other major works, the species skulduggery by Darwin or his was ever the Victorian country and animals by selecting theory took longer than he cronies, as is often claimed gentleman (see “Getting to know desirable individuals to originally imagined. By early today. The underdog version Darwin”, opposite), it seemed breed from. In so doing, they 1858, he had drafted many of Wallace’s story emerged like the noble thing to do. emphasised some traits and chapters and was about a year only after the 1950s. Lyell and another of Darwin’s reduced others (see “Evolution or two away from publishing his Wallace had long been peers, Joseph Dalton Hooker, in a nutshell”, opposite) “big book”, which would have privately convinced that did not agree with that view. It would take Darwin more spanned several volumes. species must evolve. But he They had been aware of Darwin’s than 20 years to publish these was certainly not, as many theory for years and were not ideas. In recent decades it has modern commentators put prepared to withhold their become widely believed that WORDS FROM Wallace it, searching for a mechanism knowledge of Darwin’s priority. Darwin kept his evolutionary Then, on 18 June, something for how evolution works. As he They proposed a compromise: theorising a secret and delayed surprising happened. An essay collected thousands of tropical to present Wallace’s essay its publication because he was arrived in the mail from Alfred insects and birds, his theoretical together with some of Darwin’s afraid of the reaction. A large Russel Wallace, outlining a views gradually matured. unpublished writings at a body of literature emerged theory almost identical to In February 1858, on the tiny meeting of the Linnean Society proposing reasons for this: for Darwin’s own. spice island of Ternate, Wallace of London. Modern opinions example, that he was put off by Wallace was a brilliant lay sweating from fever when about these arrangements can the fierce reception to the 1844 collector who had worked in he thought of a means whereby be strong indeed, especially evolutionary potboiler Vestiges Southeast Asia since 1854. There species could become naturally among those who think Wallace of the Natural History of are perhaps even more myths adapted to a changing world. It was unfairly treated. This is Creation, or that he was afraid about him than Darwin. was a filtering process of life and another mid-20th century view. of offending his religious wife. Wallace is often portrayed as death that was very similar to According to the standards of the

38 | NewScientist | 16 July 2016 In further Instant Experts on evolution, we look at the future of evolution and how genetics became incorporated into our understanding of Darwin’s ideas.

Getting to know darwin time, however, the arrangement the revelation that no divine was fair. Wallace had sent his guiding hand was needed; essay without asking for it to be species evolve on their own. kept private. The conventions of But Darwin also gained ine the day allowed Darwin or Lyell strong support especially v

to publish it. Wallace was always from members of the younger eye / o accorded the honour of being the generation of naturalists, such ntrast Co co-discoverer of natural selection as (today O

and never tired of expressing his always referred to as Darwin’s NTRAST O C ia gratitude and satisfaction. bulldog, but not known as this z These brief writings of Darwin in his lifetime). Darwin’s mass gen

and Wallace offered the first of evidence, ranging from A / G.B.B. o i v i h

statement of how species came embryology and vestigial organs rc A into existence by natural means, to geographical distribution, yet they made remarkably little and his arguments in favour of William, Charles Darwin’s eldest child, impact. Urged to bring out a evolution were overwhelming. was also the subject of his father’s studies reduced overview of his massive Despite its baptism of fire, work in progress, Darwin spent On the Origin of Species almost For someone who devised a revolutionary idea, Charles 13 months condensing his single-handedly convinced the Darwin lived a remarkably quiet life. In 1842, Darwin and 20 years of study into a single international scientific his wife Emma moved from London to rural Kent in southern volume. This was published on community that evolution was a England. They already had two children then, and would go 24 November 1859 as On the fact. In his 1889 book Darwinism, on to have eight more. Origin of Species. Wallace wrote of the revolution Darwin had very regular habits. He rose early and went for The book was immediately Darwin effected: “this totally a walk. After breakfast he worked in his study until 9.30 am, controversial and widely reviewed unprecedented change in public his most productive time of the day, then read his letters lying and discussed. Darwin came in for opinion has been the result of on the sofa before returning to work. a great deal of ridicule and abuse. the work of one man, and was At midday he would go for another walk accompanied by The implication that human brought about in the short his dog, stopping at his greenhouse to inspect his botanical beings must have evolved from space of twenty years!” experiments. Then he would proceed to the sand walk, a earlier species was particularly The theory of evolution has gravel path around a strip of woodland. While strolling on objectionable to many, as was come a long way since. Today we this “thinking path”, Darwin would ruminate on his unsolved think of it in terms of genes and scientific problems. DNA, but Darwin and Wallace had After luncheon he read the newspaper and wrote letters. evolution no idea of their existence. It was His network of correspondents provided information from only in the 1930s and 1940s that all corners of the globe. in a nutshell genetics was incorporated into The Darwins were not very strict parents and the children Darwin’s and Wallace’s theory evolutionary theory. Even now, were apt to run wild. Their mild-mannered father worked of evolution maintains that new new discoveries are shaking up patiently to a background of playful screams and little species are descended from earlier our understanding, but at the footsteps stampeding past his study door. ones. This long-term process core of the modern theory After dinner Darwin played backgammon with his wife. happens because all organisms remains Darwin’s idea of descent They were very competitive. He once wrote, “Now the tally vary. The tiny variations are with modification. with my wife in backgammon stands thus: she, poor creature, naturally “selected” by virtue Today evolution has many has won only 2490 games, whilst I have won, hurrah, of whether or not they help an critics outside the scientific hurrah, 2795 games!” organism to survive the brutal community, especially in the US, Despite poor health, Darwin continued to publish a string struggle for existence in nature. where a significant percentage of of innovative and seminal works until his final book on Many are born, but few survive; the population are creationists. earthworms in 1881. It was an instant bestseller. He died fortuitous variations are What is forgotten is that the the following year, aged 73. preferentially passed on. This scientific debate over evolution But science had one last claim on him. Rather than a quiet process of endless filtering works was over by the 1870s and has internment in the local churchyard, which he called “the to adapt organisms to their never again been a matter of sweetest place on Earth”, Darwin was given a state funeral environment. serious dispute. n in London’s Westminster Abbey.

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