Most of the lectures were on Darwinism evolution through natural selection , but he also gave speeches on biogeography , spiritualism, and socio-economic reform. During the trip, he was reunited with his brother John who had emigrated to California years before. He also spent a week in Colorado, with the American botanist Alice Eastwood as his guide, exploring the flora of the Rocky Mountains and gathering evidence that would lead him to a theory on how glaciation might explain certain commonalities between the mountain flora of Europe, Asia and North America, which he published in in the paper "English and American Flowers".
He met many other prominent American naturalists and viewed their collections.
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His book Darwinism used information he collected on his American trip, and information he had compiled for the lectures. On 7 November , Wallace died at home in the country house he called Old Orchard, which he had built a decade earlier. His death was widely reported in the press. The New York Times called him "the last of the giants belonging to that wonderful group of intellectuals that included, among others, Darwin, Huxley, Spencer, Lyell, and Owen, whose daring investigations revolutionised and evolutionised the thought of the century.
Some of Wallace's friends suggested that he be buried in Westminster Abbey , but his wife followed his wishes and had him buried in the small cemetery at Broadstone, Dorset.
The medallion was unveiled on 1 November Unlike Darwin, Wallace began his career as a travelling naturalist already believing in the transmutation of species. It was widely discussed, but not generally accepted by leading naturalists, and was considered to have radical , even revolutionary connotations. He was also profoundly influenced by Robert Chambers ' work, Vestiges of the Natural History of Creation , a highly controversial work of popular science published anonymously in that advocated an evolutionary origin for the solar system, the earth, and living things.
I have a rather more favourable opinion of the 'Vestiges' than you appear to have.
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I do not consider it a hasty generalization, but rather as an ingenious hypothesis strongly supported by some striking facts and analogies, but which remains to be proven by more facts and the additional light which more research may throw upon the problem. It furnishes a subject for every student of nature to attend to; every fact he observes will make either for or against it, and it thus serves both as an incitement to the collection of facts, and an object to which they can be applied when collected.
I should like to take some one family [of beetles] to study thoroughly, principally with a view to the theory of the origin of species. By that means I am strongly of opinion that some definite results might be arrived at. Wallace deliberately planned some of his field work to test the hypothesis that under an evolutionary scenario closely related species should inhabit neighbouring territories.
His conclusion that "Every species has come into existence coincident both in space and time with a closely allied species" has come to be known as the "Sarawak Law". Wallace thus answered the question he had posed in his earlier paper on the monkeys of the Amazon river basin. Although it contained no mention of any possible mechanisms for evolution, this paper foreshadowed the momentous paper he would write three years later.
The paper shook Charles Lyell's belief that species were immutable. Although his friend Charles Darwin had written to him in expressing support for transmutation, Lyell had continued to be strongly opposed to the idea. Around the start of , he told Darwin about Wallace's paper, as did Edward Blyth who thought it "Good! Upon the whole! Wallace has, I think put the matter well; and according to his theory the various domestic races of animals have been fairly developed into species.
Uses my simile of tree [but] it seems all creation with him. Darwin had already shown his theory to their mutual friend Joseph Hooker and now, for the first time, he spelt out the full details of natural selection to Lyell. Although Lyell could not agree, he urged Darwin to publish to establish priority. Darwin demurred at first, then began writing up a species sketch of his continuing work in May By February , Wallace had been convinced by his biogeographical research in the Malay Archipelago of the reality of evolution.
As he later wrote in his autobiography:. The problem then was not only how and why do species change, but how and why do they change into new and well defined species, distinguished from each other in so many ways; why and how they become so exactly adapted to distinct modes of life; and why do all the intermediate grades die out as geology shows they have died out and leave only clearly defined and well marked species, genera, and higher groups of animals?
According to his autobiography, it was while he was in bed with a fever that Wallace thought about Thomas Robert Malthus 's idea of positive checks on human population growth and came up with the idea of natural selection.
Alfred Russel Wallace - Wikipedia
He used this house as a base camp for expeditions to other islands such as Gilolo. It then occurred to me that these causes or their equivalents are continually acting in the case of animals also; and as animals usually breed much more quickly than does mankind, the destruction every year from these causes must be enormous in order to keep down the numbers of each species, since evidently they do not increase regularly from year to year, as otherwise the world would long ago have been crowded with those that breed most quickly.
Vaguely thinking over the enormous and constant destruction which this implied, it occurred to me to ask the question, why do some die and some live? And the answer was clearly, on the whole the best fitted live In this way every part of an animals organization could be modified exactly as required, and in the very process of this modification the unmodified would die out, and thus the definite characters and the clear isolation of each new species would be explained.
Wallace had once briefly met Darwin, and was one of the correspondents whose observations Darwin used to support his own theories. Although Wallace's first letter to Darwin has been lost, Wallace carefully kept the letters he received. On 18 June , Darwin received the essay from Wallace. While Wallace's essay obviously did not employ Darwin's term "natural selection", it did outline the mechanics of an evolutionary divergence of species from similar ones due to environmental pressures.
In this sense, it was very similar to the theory that Darwin had worked on for twenty years, but had yet to publish. Darwin sent the manuscript to Charles Lyell with a letter saying "he could not have made a better short abstract! Even his terms now stand as heads of my chapters Wallace's essay was presented to the Linnean Society of London on 1 July , along with excerpts from an essay which Darwin had disclosed privately to Hooker in and a letter Darwin had written to Asa Gray in Communication with Wallace in the far-off Malay Archipelago was impossible without months of delay, so he was not part of this rapid publication.
Fortunately, Wallace accepted the arrangement after the fact, happy that he had been included at all, and never expressed public or private bitterness. Darwin's social and scientific status was far greater than Wallace's, and it was unlikely that, without Darwin, Wallace's views on evolution would have been taken seriously. Lyell and Hooker's arrangement relegated Wallace to the position of co-discoverer, and he was not the social equal of Darwin or the other prominent British natural scientists. However, the joint reading of their papers on natural selection associated Wallace with the more famous Darwin.
This, combined with Darwin's as well as Hooker's and Lyell's advocacy on his behalf, would give Wallace greater access to the highest levels of the scientific community. When Wallace returned to the UK, he met Darwin. Although some of Wallace's iconoclastic opinions in the ensuing years would test Darwin's patience, they remained on friendly terms for the rest of Darwin's life. Over the years, a few people have questioned this version of events.
In the early s, two books, one written by Arnold Brackman and another by John Langdon Brooks, even suggested not only that there had been a conspiracy to rob Wallace of his proper credit, but that Darwin had actually stolen a key idea from Wallace to finish his own theory. These claims have been examined in detail by a number of scholars who have not found them to be convincing. After the publication of Darwin's On the Origin of Species , Wallace became one of its staunchest defenders on his return to England in In one incident in that particularly pleased Darwin, Wallace published the short paper "Remarks on the Rev.
Haughton's Paper on the Bee's Cell, And on the Origin of Species" in order to rebut a paper by a professor of geology at the University of Dublin that had sharply criticised Darwin's comments in the Origin on how hexagonal honey bee cells could have evolved through natural selection. An even lengthier defence of Darwin's work was "Creation by Law", a review Wallace wrote in for the Quarterly Journal of Science of the book The Reign of Law , which had been written by George Campbell , the 8th Duke of Argyll, as a refutation of natural selection.
Historians of science have noted that, while Darwin considered the ideas in Wallace's paper to be essentially the same as his own, there were differences. Bowler , have suggested the possibility that in the paper he mailed to Darwin, Wallace was not discussing selection of individual variations at all but rather group selection. Others have noted that another difference was that Wallace appeared to have envisioned natural selection as a kind of feedback mechanism keeping species and varieties adapted to their environment.
The action of this principle is exactly like that of the centrifugal governor of the steam engine, which checks and corrects any irregularities almost before they become evident; and in like manner no unbalanced deficiency in the animal kingdom can ever reach any conspicuous magnitude, because it would make itself felt at the very first step, by rendering existence difficult and extinction almost sure soon to follow. The cybernetician and anthropologist Gregory Bateson would observe in the s that, though writing it only as an example, Wallace had "probably said the most powerful thing that'd been said in the 19th Century".
In , Darwin wrote to Wallace about a problem he was having understanding how some caterpillars could have evolved conspicuous colour schemes.
Alfred Russel Wallace
Darwin had come to believe that sexual selection , an agency to which Wallace did not attribute the same importance as Darwin did, explained many conspicuous animal colour schemes. However, Darwin realised that this could not apply to caterpillars. Wallace responded that he and Henry Bates had observed that many of the most spectacular butterflies had a peculiar odour and taste, and that he had been told by John Jenner Weir that birds would not eat a certain kind of common white moth because they found it unpalatable.
Darwin was impressed by the idea.
At a subsequent meeting of the Entomological Society, Wallace asked for any evidence anyone might have on the topic. Warning coloration was one of a number of contributions Wallace made in the area of the evolution of animal coloration in general and the concept of protective coloration in particular. In his book Tropical Nature and Other Essays , he wrote extensively on the coloration of animals and plants and proposed alternative explanations for a number of cases Darwin had attributed to sexual selection.
In , he wrote a critical review in Nature of his friend Edward Bagnall Poulton 's The Colours of Animals which supported Darwin on sexual selection, attacking especially Poulton's claims on the "aesthetic preferences of the insect world". In , Wallace wrote the book Darwinism , which explained and defended natural selection. In it, he proposed the hypothesis that natural selection could drive the reproductive isolation of two varieties by encouraging the development of barriers against hybridisation.
Thus it might contribute to the development of new species. He suggested the following scenario. When two populations of a species had diverged beyond a certain point, each adapted to particular conditions, hybrid offspring would be less well-adapted than either parent form and, at that point, natural selection will tend to eliminate the hybrids.
Furthermore, under such conditions, natural selection would favour the development of barriers to hybridisation, as individuals that avoided hybrid matings would tend to have more fit offspring, and thus contribute to the reproductive isolation of the two incipient species. This idea came to be known as the Wallace effect ,  later referred to as reinforcement.