There may be no such thing as originality. In the fourth edition of On the Origin of Species, Charles Darwin added a historical sketch to recognise those he considered had anticipated his great evolutionary idea. In a footnote he remarked on "the manner in which similar views arise at about the same time". He could have been referring to Alfred Russel Wallace, who had independently grasped the elements of natural selection while Darwin was still working slowly on his great book.

Some historians would say that the idea had come of age, distilled out of the intellectual broth at the appropriate moment, the discoverer merely giving expression to what lurked in the zeitgeist. After all, Robert Chambers had anticipated Darwin himself by 15 years: his Vestiges of the Natural History of Creation had caused a sensation. The scandalised reception of this heretical work slowed down Darwin's pen until Wallace's appearance as a rival propelled him feverishly towards publication. Ideas have their moment, it seems, and revolutions in thought their standard bearers.

Rebecca Stott has delved into the history of the idea of "transmutation" more thoroughly than did Darwin. The supreme observer was no linguist, and nor was he a historian. He thoroughly acknowledged Wallace, Chambers, his grandfather Erasmus, and the great French biologist Jean-Baptiste Lamarck, but the rest of his list was a bit like a blunderbuss fired into a flock of possible predecessors, scoring a few rather arbitrary hits. Stott's list is more interesting. She has revealed an extraordinary batch of free thinkers who dared to consider mutability during times when such ideas might still cost the thinker his head.

Some of these radicals are well known. The encyclopaedist Denis Diderot danced an elaborate pas de deux around the Parisian censor for years by devising cunning literary disguises for notions that were anathema to the Catholic establishment. Leonardo da Vinci (inevitably) had relevant thoughts about natural processes, though wrapped up in the arcane camouflage of his notebooks. But I knew nothing about Benoît de Maillet, the French consul in Cairo, who already in the early years of the 18th century was synthesising ideas about a great age for the Earth with notions concerning descent of animals from a common origin in the sea.

He disguised himself in publishing as an Indian sage called Telliamed, who was quizzed by an (unnamed) French missionary to reveal these ancient truths. The tail-to-head anagram of the former seems rather obvious, perhaps, but De Maillet died in his bed at a considerable age. Perhaps it was his eyewitness accounts of mermaids that allowed science to forget him.

Nor had I previously encountered Abraham Tremblay, private tutor to the rich and influential Dutch Bentinck family. During the first half of the 18th century Tremblay investigated meticulously and methodically the wondrous polyp  a common pond organism that could regenerate indefinitely from the smallest fragment. Under his own design of microscope he demonstrated this phenomenon time and again, dispatching samples with instructions to persuade the many sceptics that here was something that seemed to lie halfway between the plant and animal kingdoms. It made Tremblay famous. But it also blurred categories. It worried philosophers accustomed to clear and inviolable boundaries made by the Creator. The hydra even spawned satirical verses. Would Higgs boson have the same effect today?

Earlier still, in France, a Huguenot potter called Bernard Palissy had been decorating a grotto for Catherine de Medici with brilliant ceramics, modelled from the life, of pond creatures writhing and intertwined in a kind of petrified version of "nature red in tooth and claw". Stott proves that this was no mere decorative whim. Palissy believed that organisms could be generated in clay ponds by a kind of alchemical brew  a theory curiously similar to some current theories on the origin of life itself.

Perhaps he was inspired by the clay he worked on to think of a kind of transformational flux, a spontaneous generation that could explain fossils and frogs at a stroke. Although not formally educated, Palissy delivered public addresses that were extremely popular with the gentry. His published lectures, modestly entitled "Admirable Discourses", then fell into obscurity, but those who believe in the transmission of ideas would probably say they contributed to a kind of intellectual mulch from which subsequent ideas grew.

Stott has tracked down a ninth century Abbasid empire scholar called al-Jahiz, an acute observer supplying an intellectual bridge between Renaissance thinkers and the great Aristotle  probably the first philosopher to observe nature closely for unvarnished facts during his obsessive years around the lagoon on the Greek island of Lesbos. It is an intriguing connection, and Darwin would have been delighted by it in his generous way.

Jahiz was an ecologist rather than an evolutionist. He marvelled at how many different organisms were so perfectly adapted, at links between predator and prey, and how different environments suited different creatures. I confess that I had never heard of his book, Living Beings, but that is my deficiency. To Jahiz, every species was an illustration of Allah's design, making a perfect jigsaw puzzle where every piece had a unique and allocated place. No hint of evolution there.

Every character that Stott introduces has a riveting story to tell, and all their histories are told with style and historical nous. I feel enriched for having learned about De Maillet, Tremblay, Palissy and al-Jahiz. There remains, though, the question of whether a tradition of "transmutation" really influenced Darwin. Was he the successor of a suppressed current of speculation, a species of samizdat thought that finally had its day when the grip of religion weakened? The identification of a long line of intellectual "ancestors" carries with it an implication of this kind. Doubtless, the 19th century was truly the right time for evolution to emerge from the shadows.

Yet Darwin always strikes his readers as a "bottom up" thinker, not quite Baconian in a devotion to facts before generating theory, but nonetheless somebody who took nothing for granted until he had tested it through experiment or by collecting facts. The proof of this facet of his character lies not in evolution, but in all the other, original contributions he made to science: the origin of coral reefs, the mechanisms of fertilisation in plants, the importance of worms in soil generation, facial expression in animals  the list goes on. Every time, he approached his object of study anew.

It seems to me that, although Erasmus Darwin lay on his family tree, Charles was not receiving a subliminal message from a dead hypothesiser. As so often before and after, he was starting afresh, open to past influences, but fuelled by his Beagle voyage. Meanwhile, the world was also opening up to others with an unbiased eye, Wallace chief among them.

Stott has done a wonderful job in showing just how many extraordinary people had speculated on where we came from before the great theorist dispelled all doubts.

 Richard Fortey's Survivors: The Animals and Plants that Time has Left Behind is published by HarperPress.