24. Understanding Evolution in 1862

The meeting with Spencer had taught Wallace to be very cautious with another man who shared the same Lamarckian values. In the 1860s and 70s Richard Owen was a powerful figure at the British Museum where he used Cuvier’s methods to work out the meaning of vertebrate palaeontology.

th-3Richard Owen    220px-Herbert_SpencerHerbert Spencer

They both saw vertebrates as an archetype of design, a string of vertebrae variously making head, arms, ribs, pelvis and legs. Many more groups of animals and even plants conformed. Owen was a strange man, greatly troubled by his own past, having nightmares from his days as a surgeon’s apprentice in Lancaster jail. From those hard experiences in 1820 he had come a long way to become one of Queen Victoria’s advisors for the Great Exhibition thirty years later.  In that time he was Professor of Vertebrate Anatomy at the Royal College of Surgeons after winning notoriety with the Prince Consort and the Royal Society for his reconstructions of dinosaurs and the fossilized remains of an extinct flightless bird from New Zealand 4m high.

The Manchester Spectator reviewed one of his lectures in 1849 and gave a flavor of the man: “Richard Owen undertakes to demonstrate scientifically that the arms and legs of the human race are the later and higher developments of the ruder wings and fins of the vertebrate animals …. he concludes that God has not peopled the globe by successive creations, but by the operation of general laws.” He stuck to this same idea ten years later to the British Association in 1858, where he spoke glowingly of Lamarck and “the continuous operation of Creative Power”.

Few scientists have ever had a worse reputation in all recorded aspects of their lives than Richard Owen. Because so many scientists hated him, this often caused them to gang up and irritate him even more. Huxley shared his specialism in vertebrate palaeontology and after his famous public rebuke of Owen’s jealous reaction to The Origin, the two men didn’t exchange a civil word with one another. Huxley was powerful enough to encourage others to oppose Owen, who became a loner as well as an angry old man, always causing unnecessary trouble and resentment.

Mining in Belgium during the 1860s had yielded rich collections of Iguanodon fossils, and they showed clearly that the giant dinosaur had stood on its two hind legs. This stirred up the old argument between Owen and Mantell, proving both to have been wrong on some points. Mantell had died in 1852, missing the discoveries and a thin admission of defeat from Owen. More new dinosaur fossils were found in many of the rocks exposed by the surge in railway building when the American Civil War ended in 1865 and the palaeontologists ED Cope and OC Marsh took the work to another level by the end of the century with evolving lineages of different species of horses.

In the Summer of 1862 Wallace stayed with the Darwins in their home at Down House.

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It was the first time the two men had met and what could have been a difficult encounter turned out to be a pleasant weekend, politely sharing their many compatible experiences, though from very different backgrounds. Darwin enjoyed the chance to reflect on the time in 1836 when he also had returned to London, after four years away on the Beagle voyage. He had gained similar inspiration from the rich tropical forests, the vast grasslands and the colourful corals. He had also thought of the consequences of the writings by Malthus and Lyell and he had also written notes of these early ideas of evolution. Darwin scribbled his first famous drawing of a branched evolutionary tree in 1837 and wrote a draft essay about natural selection in the Spring of 1842 just before he and his wife Emma left London to live at the village of Downe in Kent. But he thought that he didn’t yet have a case and he put the writing to one side.

There in Kent, the Darwin family settled into a busy but simple rhythm of Victorian country life, kindly and loving, and Charles decided to take his time building up support for natural selection before he submitted a manuscript for publication. He knew that some of his ideas needed experimental evidence, inheritance and migration for example being large issues. And he needed to build up his own confidence in those ideas, fearing the political and religious storms that his presentation was bound to cause. Nevertheless, he continued from 1854 until 1858 to write several versions of his argument, a 231 page sketch in 1844, and what his family called the Big Species Book. That was what he was writing when Wallace’s own manuscript arrived for Lyell to check through in June 1858. Now, Wallace was spending his first weekend at Downe and they were sharing the excitement of their work quite happily.

books    The Big Species Book – only recently published – by Cambridge University Press

No-one was more delighted about this than Wallace himself and that cheered-up Darwin immensely. The relief shows up in one of Charles’ early reactions, that “he rates me much too highly and himself much too lowly. What strikes me most about Wallace is the absence of jealousy towards me.” Wallace’s concurrent view of Darwin was of the quiet Englishman proud to be in the middle: socially, politically and philosophically.

Darwin had no such affiliation. He was out on his own, beholden to no-one, with his own investment income. He was a holistic thinker: had formally studied biology, medicine, theology and geology. He became experienced as an observer and explorer, a writer, a taxonomist, a pigeon-fancier and a plant physiologist. He remained interested in all these things and more. That was his strength, and to Wallace’s envy he had a loving family and a sense of humour. His Cambridge influences were showing through: the updated scientific methods being advocated there by the philosopher William Whewell and the desire to analyse the results, the intuition of his mathematical cousin Francis Galton. Their influence on biological problems was just beginning.

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Francis Galton                                                                                     William Whewell

Whewell (1794-1866) had gone against the trend toward specialization and prided himself in his wide range of interests, which included geology, physics, astronomy and economics, and had a hunch that together they would show him some general patterns. He had felt that Bacon’s deductive methods, reducing scientific issues to singular logic, were either too simplistic or too complicated to resolve. Useful though they had clearly turned out to be Whewell wanted more invention, sagacity and genius. He was afraid that scientists were losing sight of the soul inside the systems they studied and he thought that creativity could bring it back. Only pluralists like him, with really broad overviews, could create general scientific laws or even theories.

Darwin and Wallace both knew there was a new approach in biology that was a good example of the kind of thing Whewell had in mind, an interdisciplinary view of global biology to which Wallace was eminently attached. Now we call it biogeography, and in 1876 Wallace’s The Geographical Distribution of Animals was an early example. He was able to add a lot of new data from his travels in South America and East Asia and to test out some of the theories to explain the intercontinental migration of animals and plants.

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Darwin was famously skeptical of the land bridges being used to explain the movements first proposed by young Edward Forbes who had died in 1854. He thought there had only been the wide oceans, which was why he had spent so much time testing how long seeds could stay afloat in the currents. But Wallace had grander ideas, mapping the ranges of whole floras and faunas and suggesting climatic and migratory restrictions.

220px-Gideon_Mantell_engaged_in_battle_by_Edward_Forbes      Forbesfrontispiece These cartoons are by Edward Forbes, one of Gideon Mantell chasing flying dinosaurs (1830) and the other for his book Natural History of European Seas 1859.

Another of Wallace’s new acquaintances from his exploration of the London scientific community was secretary at the London Zoo, Philip Sclater, and they quickly established a good relationship. They had both noticed a similarity between mammals of Madagascar and mainland Africa, and wondered about the reality of invoking a lost continent in the southern hemisphere to account for it. Sclater even gave it a name, Lemuria, and the idea was soon picked up by the great German biologist Ernst Haeckel in his 1868 Natural History of Creation but there was no direct evidence. It turned out that this book was much more widely read than the Origin and went through 12 editions before Haeckel died in 1919. In those days, a lot of ideas that touched on scientific problems were not backed up by evidence, though for its place and time the book was a lively mix of myth, science and philosophy.

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Haeckel’s enthusiasm for the similarities between the developmental changes in an embryo and some lineages of related species became well known as his Biogenetic Law, that embryology reflects phylogeny. He had series of pictures from mammals, birds and fish showing their embryo growing through phases similar to what may once have been mature creatures, now extinct. Humans had the longest lineage, from early life on earth starting as a single cell, dividing to a cup-shaped form similar to so many marine organisms, then to resemble an early fish with gills and finally mammals and humans.  The idea picked up a lot of support in the 1860s, especially in the United States, where Alpheus Hyatt had reconstructed pathways of fossils through geological time. One showed how snails may have evolved, examples about which he had corresponded with Darwin many times.

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Hyatt and his supporters extended these embryological pathways of evolution, thinking they would have continued under their own control, away from environmental influence, until an unworkable form led to extinction of the lineage: a missing link too far, caused by some internally programmed trait. They used the theory to explain many very different trends that were showing up in some other kinds of fossils. For example, they thought this kind of runaway development might explain why the antlers of the Irish Elk became too long for the species’ survival, why the extended canines of sabre-toothed cats might have the same effect, and why the self-strangulation of the oyster Gryphea eventually killed the creature. Darwin was not impressed and the lack of further evidence for Hyatt‘s explanations lost what little support the work had.

Most interest in evolution at that time centred on how biodiversity increased through geological time. Haeckel, however, was considering the opposite as well, and he realized that if evolution can move one way so it can also go the other. As selection took place so individuals of the earlier species separated into either the more-progressive or the less-progressive forms. The less-progressive ones chose to settle on smaller territory as their numbers reduced if the environment stayed hostile, or as they recovered when often it didn’t. There was going to be more interest in this kind of negative progress later, when several biologists considered it as a common feature of evolution. They called it ‘degeneration’ and it was thought to explain variations of varieties or races within species.

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