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ay a believer in the idea that evolutionary changes happen notgradually but suddenly。 saltationists （the word es from the latin for 鈥渓eap鈥潱ouldn鈥檛accept that plicated organs could ever emerge in slow stages。 what good； after all； is one…tenth of a wing or half an eye？ such organs； they thought； only made sense if they appeared ina finished state。
the belief was surprising in as radical a spirit as huxley because it closely recalled a veryconservative religious notion first put forward by the english theologian william paley in1802 and known as argument from design。 paley contended that if you found a pocket watchon the ground； even if you had never seen such a thing before； you would instantly perceivethat it had been made by an intelligent entity。 so it was； he believed； with nature： itsplexity was proof of its design。 the notion was a powerful one in the nineteenth century；and it gave darwin trouble too。 鈥渢he eye to this day gives me a cold shudder；鈥潯eacknowledged in a letter to a friend。 in the origin he conceded that it 鈥渟eems； i freely confess；absurd in the highest possible degree鈥潯hat natural selection could produce such an instrumentin gradual steps。
even so； and to the unending exasperation of his supporters； darwin not only insisted thatall change was gradual； but in nearly every edition of origin he stepped up the amount of timehe supposed necessary to allow evolution to progress； which pushed his ideas increasingly outof favor。 鈥渆ventually；鈥潯ccording to the scientist and historian jeffrey schwartz； 鈥渄arwin lostvirtually all the support that still remained among the ranks of fellow natural historians andgeologists。鈥�
ironically； considering that darwin called his book on the origin of species； the one thinghe couldn鈥檛 explain was how species originated。 darwin鈥檚 theory suggested a mechanism forhow a species might bee stronger or better or faster鈥攊n a word； fitter鈥攂ut gave noindication of how it might throw up a new species。 a scottish engineer； fleeming jenkin；considered the problem and noted an important flaw in darwin鈥檚 argument。 darwin believedthat any beneficial trait that arose in one generation would be passed on to subsequentgenerations； thus strengthening the species。
jenkin pointed out that a favorable trait in one parent wouldn鈥檛 bee dominant insucceeding generations； but in fact would be diluted through blending。 if you pour whiskeyinto a tumbler of water； you don鈥檛 make the whiskey stronger； you make it weaker。 and if youpour that dilute solution into another glass of water； it bees weaker still。 in the same way；any favorable trait introduced by one parent would be successively watered down by subsequent matings until it ceased to be apparent at all。 thus darwin鈥檚 theory was not a recipefor change； but for constancy。 lucky flukes might arise from time to time； but they wouldsoon vanish under the general impulse to bring everything back to a stable mediocrity。 ifnatural selection were to work； some alternative； unconsidered mechanism was required。
unknown to darwin and everyone else； eight hundred miles away in a tranquil corner ofmiddle europe a retiring monk named gregor mendel was ing up with the solution。
mendel was born in 1822 to a humble farming family in a backwater of the austrianempire in what is now the czech republic。 schoolbooks once portrayed him as a simple butobservant provincial monk whose discoveries were largely serendipitous鈥攖he result ofnoticing some interesting traits of inheritance while pottering about with pea plants in themonastery鈥檚 kitchen garden。 in fact； mendel was a trained scientist鈥攈e had studied physicsand mathematics at the olm眉tz philosophical institute and the university of vienna鈥攁nd hebrought scientific discipline to all he did。 moreover； the monastery at brno where he livedfrom 1843 was known as a learned institution。 it had a library of twenty thousand books and atradition of careful scientific investigation。
before embarking on his experiments； mendel spent two years preparing his controlspecimens； seven varieties of pea； to make sure they bred true。 then； helped by two full…timeassistants； he repeatedly bred and crossbred hybrids from thirty thousand pea plants。 it wasdelicate work； requiring them to take the most exacting pains to avoid accidental cross…fertilization and to note every slight variation in the growth and appearance of seeds； pods；leaves； stems； and flowers。 mendel knew what he was doing。
he never used the word gene 鈥攊t wasn鈥檛 coined until 1913； in an english medicaldictionary鈥攖hough he did invent the terms dominant and recessive。 what he established wasthat every seed contained two 鈥渇actors鈥潯r 鈥渆lemente；鈥潯s he called them鈥攁 dominant oneand a recessive one鈥攁nd these factors； when bined； produced predictable patterns ofinheritance。
the results he converted into precise mathematical formulae。 altogether mendel spenteight years on the experiments； then confirmed his results with similar experiments onflowers； corn； and other plants。 if anything； mendel was too scientific in his approach； forwhen he presented his findings at the february and march meetings of the natural historysociety of brno in 1865； the audience of about forty listened politely but was conspicuouslyunmoved； even though the breeding of plants was a matter of great practical interest to manyof the members。
when mendel鈥檚 report was published； he eagerly sent a copy to the great swiss botanistkarl…wilhelm von n？geli； whose support was more or less vital for the theory鈥檚 prospects。
unfortunately； n？geli failed to perceive the importance of what mendel had found。 hesuggested that mendel try breeding hawkweed。 mendel obediently did as n？geli suggested；but quickly realized that hawkweed had none of the requisite features for studying heritability。
it was evident to him that n？geli had not read the paper closely； or possibly at all。 frustrated；mendel retired from investigating heritability and spent the rest of his life growingoutstanding vegetables and studying bees； mice； and sunspots； among much else。 eventuallyhe was made abbot。
mendel鈥檚 findings weren鈥檛 quite as widely ignored as is sometimes suggested。 his studyreceived a glowing entry in the encyclopaedia britannica 鈥攖hen a more leading record of scientific thought than now鈥攁nd was cited repeatedly in an important paper by the germanwilhelm olbers focke。 indeed； it was because mendel鈥檚 ideas never entirely sank below thewaterline of scientific thought that they were so easily recovered when the world was readyfor them。
together； without realizing it； darwin and mendel laid the groundwork for all of lifesciences in the twentieth century。 darwin saw that all living things are connected； thatultimately they 鈥渢race their ancestry to a single； mon source；鈥潯hile mendel鈥檚 workprovided the mechanism to explain how that could happen。 the two men could easily havehelped each other。 mendel owned a german edition of the origin of species； which he isknown to have read； so he must have realized the applicability of his work to darwin鈥檚； yet heappears to have made no effort to get in touch。 and darwin for his part is known to havestudied focke鈥檚 influential paper with its repeated references to mendel鈥檚 work； but didn鈥檛connect them to his own studies。
the one thing everyone thinks featured in darwin鈥檚 argument； that humans are descendedfrom apes； didn鈥檛 feature at all except as one passing allusion。 even so； it took no great leap ofimagination to see the implications for human development in darwin鈥檚 theories； and itbecame an immediate talking point。
the showdown came on saturday； june 30； 1860； at a meeting of the british associationfor the advancement of science in oxford。 huxley had been urged to attend by robertchambers； author of vestiges of the natural history of creation； though he was still unawareof chambers鈥檚 connection to that contentious tome。 darwin； as ever； was absent。 the meetingwas held at the oxford zoological museum。 more than a thousand people crowded into thechamber； hundreds more were turned away。 people knew that something big was going tohappen； though they had first to wait while