Born in Monmouthshire in 1823, the fifth child of downwardly mobile middle class parents, Wallace left school at 14. Working as a builder’s surveyor in London, he studied at the ‘Hall of Science’ off Tottenham Court Road and visited the zoo. In 1848, he embarked on a specimen collecting trip to the Amazon basin. Four years later, he boarded a ship, the Helen, bound for London.
Twenty-four days into the voyage, the Helen’s cargo caught fire and Wallace’s collection of specimens was lost. He saved only part of his diary and a few sketches. A parrot also survived. After ten days in an open boat, Wallace and his companions were rescued but their ordeal wasn’t over. With insufficient food for the extra people on board, they had to eat rats and lick the fat off cooking pots. The rescuing ship almost sank in a gale.
Undaunted, Wallace resumed his collecting activities. In 1854, he travelled to the Malay Archipelago. He would spend eight years there gathering specimens, including some of the famous birds of paradise, and meticulously recording the locations of the finds.
Wallace was not just a superb field naturalist, but a theoretician who reflected deeply on what he found. A voracious reader, he had read the scientific literature of his day. His youth on the Welsh-English border, made him sensitive to the differences boundaries make to accents and behaviour.
The fauna on each side of the Rio Negro, he noticed, showed similar differences; if God had created the animals, as the Bible claimed, why had he made them different on each side of a river? Those of Lombok are unlike the ones in Bali. Cockatoos, for example, occur on Lombok but not on Bali. Indeed, animals to the west of the Malay Archipelago were related to Asiatic species whereas those to the east were Australasian. The division between the two is known today as the Wallace Line.
His evolutionary insight came during a malarial fever. Hovering between life and death, he remembered Malthus’ idea that populations are kept in check by disease and adversity. Only the fittest survive this weeding out process and bequeath their genes to subsequent generations.
His paper On the tendency of variations to depart indefinitely from the original type put forward the Principle of Natural Selection. He sent it to Darwin, who was devastated. He had been collecting evidence for this idea for 20 years but, fearing a backlash from the religious establishment, had not published. Now Wallace had beaten him to the post.
Although it was highly irregular to do so, colleagues arranged for Wallace’s paper and excerpts from Darwin’s diary to be read to a meeting of the Linnaean Society on Jul 1, 1858. Darwin wasn’t present; his baby son had died of scarlet fever.
Wallace, whose permission had not been sought for the reading, was still in the Far East. Only one of the 30 or so people present at the most important scientific event of the 19th Century commented; Samuel Haughton of Trinity College Dublin declared that ‘all that was new in them (the papers) was false and what was true was old’.
Had Wallace sent the paper to an editor for publication, his name, not Darwin’s, would be on everyone’s lips today. Despite his extraordinary courage in voyaging to unknown lands, he was in awe of the great and the good. He had sent the paper to the only potential rival in his field.
Wallace returned to London, an accepted member of the scientific elite, although overshadowed by Darwin. He was one of the first scientists to raise concerns about the impact of human activities on flora and fauna. He invested badly, turned to spiritualism and fell on lean times. Darwin secured him a modest pension.