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. John van Wyhe 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 Charles Darwin 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 M ry O Charles Robert Darwin is born in Shrewsbury, UK, Hist 1809 the fifth of six children in a prosperous family atural N E 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 On the Origin of Species 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.