http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=A12&pageseq=1 "...p.7,8 Lucretius" The mechanical shock of the atoms being in his view the all-sufficient cause of things, he combats the notion that the constitution of nature has been in any way determined by intelligent design. The inter-action of the atoms throughout infinite time rendered all manner of combinations possible. Of these the fit ones persisted, while the unfit ones disappeared. Not after sage deliberation did the atoms station themselves in their right places, nor..."
"...p.22 During the Middle Ages the doctrine of atoms had to all appearance vanished from discussion. In all probability it held its ground among sober-minded and thoughtful men, though neither the church nor the world was prepared to hear of it with tolerance. Once, in the year 1348, it received distinct expression. But retraction by compulsion immediately followed, and, thus discouraged, it slumbered till the seventeenth century, when it was revived by a contemporary and friend of Hobbes and Malmesbury, the orthodox Catholic provost of Digne, Gassendi. But before stating his relation to the Epicurean doctrine, it will be well to say a few words on the effect..."
Right up to our present day with "alleles" fighting it out amongst themselves: http://groups.google.com/group/talk.origins/browse_thread/thread/deac2432776866c6/b7fce5490e4d08d6#b7fce5490e4d08d6 WilliamMorse wrote 2 July 2009: "....Let me try to illustrate my thinking. The importance of a rate of increase would be if we had two alleles competing to become fixed in a population. Both of them are superior to the current predominant allele, and the one with the greatest rate of increase is the one that will become the new predominant allele. I don't think this describes any common real world scenario...."