按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
and so matters seemed destined to remain forever until one day in 1909； three months shyof the fiftieth anniversary of the publication of darwin’s on the origin of species ； when apaleontologist named charles doolittle walcott made an extraordinary find in the canadianrockies。
walcott was born in 1850 and grew up near utica； new york； in a family of modest means；which became more modest still with the sudden death of his father when walcott was aninfant。 as a boy walcott discovered that he had a knack for finding fossils； particularlytrilobites； and built up a collection of sufficient distinction that it was bought by louisagassiz for his museum at harvard for a small fortune—about 70；000 in today’s money。
although he had barely a high school education and was self taught in the sciences； walcottbecame a leading authority on trilobites and was the first person to establish that trilobiteswere arthropods； the group that includes modern insects and crustaceans。
in 1879 he took a job as a field researcher with the newly formed united states geologicalsurvey and served with such distinction that within fifteen years he had risen to be its head。 in1907 he was appointed secretary of the smithsonian institution； where he remained until hisdeath in 1927。 despite his administrative obligations； he continued to do fieldwork and towrite prolifically。 “his books fill a library shelf；” according to fortey。 not incidentally； hewas also a founding director of the national advisory mittee for aeronautics； whicheventually became the national aeronautics and space agency； or nasa； and thus canrightly be considered the grandfather of the space age。
but what he is remembered for now is an astute but lucky find in british columbia； highabove the little town of field； in the late summer of 1909。 the customary version of the storyis that walcott； acpanied by his wife； was riding on horseback on a mountain trail beneaththe spot called the burgess ridge when his wife’s horse slipped on loose stones。 dismountingto assist her； walcott discovered that the horse had turned a slab of shale that contained fossilcrustaceans of an especially ancient and unusual type。 snow was falling—winter es earlyto the canadian rockies—so they didn’t linger； but the next year at the first opportunitywalcott returned to the spot。 tracing the presumed route of the rocks’ slide； he climbed 750feet to near the mountain’s summit。 there； 8；000 feet above sea level； he found a shaleoutcrop； about the length of a city block； containing an unrivaled array of fossils from soonafter the moment when plex life burst forth in dazzling profusion—the famous cambrianexplosion。 walcott had found； in effect； the holy grail of paleontology。 the outcrop becameknown as the burgess shale； and for a long time it provided “our sole vista upon the inceptionof modern life in all its fullness；” as the late stephen jay gould recorded in his popular bookwonderful life 。
gould； ever scrupulous； discovered from reading walcott’s diaries that the story of theburgess shale’s discovery appears to have been somewhat embroidered—walcott makes nomention of a slipping horse or falling snow—but there is no disputing that it was anextraordinary find。
it is almost impossible for us whose time on earth is limited to a breezy few decades toappreciate how remote in time from us the cambrian outburst was。 if you could fly backwardsinto the past at the rate of one year per second； it would take you about half an hour to reachthe time of christ； and a little over three weeks to get back to the beginnings of human life。
but it would take you twenty years to reach the dawn of the cambrian period。 it was； in otherwords； an extremely long time ago； and the world was a very different place。
for one thing； 500…million…plus years ago when the burgess shale was formed it wasn’t atthe top of a mountain but at the foot of one。 specifically it was a shallow ocean basin at thebottom of a steep cliff。 the seas of that time teemed with life； but normally the animals left norecord because they were soft…bodied and decayed upon dying。 but at burgess the cliffcollapsed； and the creatures below； entombed in a mudslide； were pressed like flowers in abook； their features preserved in wondrous detail。
in annual summer trips from 1910 to 1925 （by which time he was seventy…five years old）；walcott excavated tens of thousands of specimens （gould says 80；000； the normallyunimpeachable fact checkers of national georgraphic say 60；000）； which he brought back towashington for further study。 in both sheer numbers and diversity the collection wasunparalleled。 some of the burgess fossils had shells； many others did not。 some were sighted；others blind。 the variety was enormous； consisting of 140 species by one count。 “the burgessshale included a range of disparity in anatomical designs never again equaled； and notmatched today by all the creatures in the world’s oceans；” gould wrote。
unfortunately； according to gould； walcott failed to discern the significance of what hehad found。 “snatching defeat from the jaws of victory；” gould wrote in another work； eightlittle piggies； “walcott then proceeded to misinterpret these magnificent fossils in the deepestpossible way。” he placed them into modern groups； making them ancestral to today’s worms；jellyfish； and other creatures； and thus failed to appreciate their distinctness。 “under such aninterpretation；” gould sighed； “life began in primordial simplicity and moved inexorably；predictably onward to more and better。”
walcott died in 1927 and the burgess fossils were largely forgotten。 for nearly half acentury they stayed shut away in drawers in the american museum of natural history inwashington； seldom consulted and never questioned。 then in 1973 a graduate student fromcambridge university named simon conway morris paid a visit to the collection。 he wasastonished by what he found。 the fossils were far more varied and magnificent than walcotthad indicated in his writings。 in taxonomy the category that describes the basic body plans ofall organisms is the phylum； and here； conway morris concluded； were drawer after drawer ofsuch anatomical sing