There is a geographical area in South-east Asia named after the scientist who first put forward the theory of evolution. This area is called "Wallacea" after Alfred Russel Wallace who co-authored, with Darwin, the 1858 scientific paper which revealed the Theory of Evolution to the world. Indeed the bulk of this paper was taken from Wallace's original work: On the Tendency of Varieties to Depart Indefinitely from the Original Type.
Students of biology in Malaysia and Indonesia are very familiar with the name "Wallace". Plants and animals have been named after him, an environmental magazine called "Wallaceana" was published by the University of Malaya, and "Wallace's Line" divides the Indonesian islands into two distinct ecological regions.
Who was this man Wallace? How did he come to think of the Theory of Evolution at the same time as Darwin, but independently of him? Why is he so well known in Asia, but less acknowledged in the West?
Unlike Darwin, who was a wealthy gentleman scientist, Wallace (some 14 years younger) was from an impoverished English family which had fallen on hard times. He left school at age 14 and was largely self-taught by reading in public libraries. He worked as a land surveyor, a builder, and a teacher.
Through the influence of his wide reading, he became a strong socialist. Wallace was also fascinated by the book "Vestiges of the Natural History of Creation", which argued that species developed one from the other, from the simple to the complex, up to and including man. He and his entomologist friend, Henry Bates, decided to go to the Amazon to look for evidence for this idea.
Wallace was 25 and Bates 23 when they set out. Having no money, they paid their way by collecting and sending specimens to museums and private collectors. Once in South America they travelled separately, and Wallace's four-year expedition ended in disaster. En route home, his ship caught fire and sank, together with thousands of specimens.
His second, eight-year long expedition was eastwards, and this is where he made his most famous discoveries. He spent this period travelling through the hundreds of tropical islands which comprise today's Indonesia and Malaysia, collecting thousands of specimens to send back to London.
He was surrounded by the wildlife of the region. The study of his vast collections gave Wallace's enquiring mind an insight which was, in many ways, deeper than Darwin's. For example, he quickly saw that there was considerable variation between individuals of any species in the wild. No one "Raja Brooke Birdwing" butterfly, for example, is exactly the same as another. He observed that individuals are genetically different from their siblings and cousins, and consequently different in form.
Wallace is considered to be the father of Biogeography, the study of the factors which determine the geographical distribution of living things. He noticed that the animals of eastern Indonesia were very different from those found to the west of an imaginary line in the sea. This is now known as Wallace's line. East of this line he saw animals related to Australian ones (kangaroos and other marsupials, and the flightless cassowary bird). To the west, the animals were related to Asian and African species (rhinoceros, tiger, and apes). In one place, the strait between the islands of Bali and Lombok, a mere 35km of sea separated these two very different communities.
We now know that Wallace's line is not imaginary at all. It's the place where the tectonic plates of Australasia and the Indo-Malayan region come together. Wallace's line follows a trench which reaches enormous depths of over 5000 metres. Even during ice ages, when the sea level falls and land bridges are created, these two regions are isolated from each other by ocean.
Wallace noted that while apes lived in the trees in Borneo, there were no apes in New Guinea. Instead he found tree-climbing kangaroos. He concluded that, in the absence of apes, kangaroos had somehow changed over generations to become tree climbers and thus exploit the apes' usual habitat in a kind of parallel universe.
In 1858, while suffering from a fever, Wallace conceived the idea that natural selection was the means by which species changed. He wrote enthusiastically to Darwin (who was already a pen- friend through their shared interest in biology). His letter included a long explanation of his theory. Darwin was shocked, since he had independently come to the same conclusion many years earlier. But being a cautious man, he had not published his theory. The letter from Wallace was the catalyst which pushed Darwin into making the Theory of Evolution public.
How is it that these two men, who had never met, came to think of the same theory at about the same time?
First, both had travelled and had become immersed in the great variety of tropical wildlife. Both had also observed the peculiar species patterns found on islands. Both had seen that many species seemed to have a common ancestor (such as Darwin's thirteen different species of finch on the Galapagos islands). Both men had thought about their observations in the light of the body of scientific knowledge of the time; such books as "Vestiges of the Natural History of Creation", the geologist Charles Lyell's works on fossils and Thomas Malthus's model of population growth.
Above all, both men had time to think. Like many new insights in science, their discovery was waiting to be born. The Theory of Evolution was itself an evolutionary step in scientific thinking.
Darwin and Wallace were very different characters. Darwin was a wealthy, gentleman biologist. In today's world he would have been a conservative university professor, obtaining research grants to pursue his ideas. Wallace was a man of much broader interests. He wrote more than 700 articles and 22 books on subjects ranging from biology to economics, sociology, glaciation, poverty, unemployment, the rights of women, spiritualism and the possibility of life on Mars.
In today's world he would have been a self-made, back-packing adventurer with a purpose, a member of the Socialist party, Amnesty International, and Greenpeace. He would have been the darling of the news media and an international celebrity, while cautious Darwin stayed in the background. Indeed by the end of his life, Wallace was reckoned to be "one of the world's most recognised names". Sadly, over the intervening years his significance has been overshadowed by the figure of Darwin.
On 7th November, 2013, please remember Alfred Russel Wallace, the other evolution man, on the centennial of his death (at age 90). And make a note for 8th of January, 2023, the bicentennial of his birth. Let's all have a party and give Wallace the recognition he most richly deserves.
by Dr Christine Betterton-Jones BSc. (Zoology), PhD (Parasitology)
Bibliography:
David Quammen, December 2008 ,The Man who wasn't Darwin - National Geographical Magazine.
Sarah Collins, January 2006 - Alfred Russel Wallace, the Architect of Evolution
The Alfred Russel Wallace Website - http://www.firstscience.com/home/articles/origins/alfred-russel-wallace-architect-of-evolution_1389.htm. Authored by Dr George Beccaloni, and George and Ed Baker.
