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there aren鈥檛 enough specialists。the stock of things to be found； examined； and recordedvery much outruns the supply of scientists available to do it。 take the hardy and little…knownorganisms known as bdelloid rotifers。 these are microscopic animals that can survive almostanything。 when conditions are tough； they curl up into a pact shape； switch off theirmetabolism； and wait for better times。 in this state； you can drop them into boiling water orfreeze them almost to absolute zero鈥攖hat is the level where even atoms give up鈥攁nd； whenthis torment has finished and they are returned to a more pleasing environment； they willuncurl and move on as if nothing has happened。 so far； about 500 species have been identified（though other sources say 360）； but nobody has any idea； even remotely； how many there maybe altogether。 for years almost all that was known about them was thanks to the work of adevoted amateur； a london clerical worker named david bryce who studied them in his sparetime。 they can be found all over the world； but you could have all the bdelloid rotifer expertsin the world to dinner and not have to borrow plates from the neighbors。
even something as important and ubiquitous as fungi鈥攁nd fungi are both鈥攁ttractsparatively little notice。 fungi are everywhere and e in many forms鈥攁s mushrooms；molds； mildews； yeasts； and puffballs； to name but a sampling鈥攁nd they exist in volumes that most of us little suspect。 gather together all the fungi found in a typical acre of meadowand you would have 2；500 pounds of the stuff。 these are not marginal organisms。 withoutfungi there would be no potato blights； dutch elm disease； jock itch； or athlete鈥檚 foot； but alsono yogurts or beers or cheeses。 altogether about 70；000 species of fungi have been identified；but it is thought the number could be as high as 1。8 million。 a lot of mycologists work inindustry； making cheeses and yogurts and the like； so it is hard to say how many are activelyinvolved in research； but we can safely take it that there are more species of fungi to be foundthan there are people to find them。
the world is a really big place。we have been gulled by the ease of air travel and otherforms of munication into thinking that the world is not all that big； but at ground level；where researchers must work； it is actually enormous鈥攅normous enough to be full ofsurprises。 the okapi； the nearest living relative of the giraffe； is now known to exist insubstantial numbers in the rain forests of zaire鈥攖he total population is estimated at perhapsthirty thousand鈥攜et its existence wasn鈥檛 even suspected until the twentieth century。 the largeflightless new zealand bird called the takahe had been presumed extinct for two hundredyears before being found living in a rugged area of the country鈥檚 south island。 in 1995 a teamof french and british scientists in tibet； who were lost in a snowstorm in a remote valley；came across a breed of horse； called the riwoche； that had previously been known only fromprehistoric cave drawings。 the valley鈥檚 inhabitants were astonished to learn that the horse wasconsidered a rarity in the wider world。
some people think even greater surprises may await us。 鈥渁 leading british ethno…biologist；鈥潯rote the economist in 1995； 鈥渢hinks a megatherium； a sort of giant ground slothwhich may stand as high as a giraffe 。 。 。 may lurk in the fastnesses of the amazon basin。鈥�
perhaps significantly； the ethnobiologist wasn鈥檛 named； perhaps even more significantly；nothing more has been heard of him or his giant sloth。 no one； however； can categorically saythat no such thing is there until every jungly glade has been investigated； and we are a longway from achieving that。
but even if we groomed thousands of fieldworkers and dispatched them to the farthestcorners of the world； it would not be effort enough； for wherever life can be； it is。 life鈥檚extraordinary fecundity is amazing； even gratifying； but also problematic。 to survey it all； youwould have to turn over every rock； sift through the litter on every forest floor； sieveunimaginable quantities of sand and dirt； climb into every forest canopy； and devise muchmore efficient ways to examine the seas。 even then you would overlook whole ecosystems。 inthe 1980s； spelunkers entered a deep cave in romania that had been sealed off from theoutside world for a long but unknown period and found thirty…three species of insects andother small creatures鈥攕piders； centipedes； lice鈥攁ll blind； colorless； and new to science。
they were living off the microbes in the surface scum of pools； which in turn were feeding onhydrogen sulfide from hot springs。
our instinct may be to see the impossibility of tracking everything down as frustrating；dispiriting； perhaps even appalling； but it can just as well be viewed as almost unbearablyexciting。 we live on a planet that has a more or less infinite capacity to surprise。 whatreasoning person could possibly want it any other way？
what is nearly always most arresting in any ramble through the scattered disciplines ofmodern science is realizing how many people have been willing to devote lifetimes to the most sumptuously esoteric lines of inquiry。 in one of his essays； stephen jay gould notes howa hero of his named henry edward crampton spent fifty years； from 1906 to his death in1956； quietly studying a genus of land snails in polynesia called partula。 over and over； yearafter year； crampton measured to the tiniest degree鈥攖o eight decimal places鈥攖he whorls andarcs and gentle curves of numberless partula； piling the results into fastidiously detailedtables。 a single line of text in a crampton table could represent weeks of measurement andcalculation。
only slightly less devoted； and certainly more unexpected； was alfred c。 kinsey； whobecame famous for his studies of human sexuality in the 1940s and 1950s。 but before hismind became filled with sex； so to speak； kinsey was an entomologist； and a dogged one atthat。 in one expedition lasting two years； he hiked 2；500 miles to assemble a collection of300；000 wasps。 how many stings he collected along the way is not； alas； recorded。
something that had been puzzling me was the question of how you assured a chain ofsuccession in these arcane fields。 clearly there cannot be many institutions in the world thatrequire or are prepared to support specialists in barnacles or pacific snails。 as we parted at thenatural history museum in london； i asked richard fortey how science ensures that whenone person goes there鈥檚 someone ready to take his place。
he chuckled rather heartily at my naivet茅。 鈥渋鈥檓 afraid it鈥檚 not as if we have substitutessitting on the bench somewhere waiting to be called in to play。 when a specialist retires or；even more unfortunately； dies； that can bring a stop to things in that field； sometimes for avery long while。鈥�
鈥渁nd i suppose that鈥檚 why you value someone who spends forty…two years studying asingle species of plant； even if it doesn鈥檛 produce anything terribly new？鈥�
鈥減recisely；鈥潯e said； 鈥減recisely。鈥潯nd he really seemed to mean it。
24 CELLS
灏彙…t…xt…澶ｅ爞
it starts with a single cell。 the first cell splits to bee two and the two bee fourand so on。 after just forty…seven doublings； you have ten thousand trillion（10；000；000；000；000；000） cells in your body and are ready to spring forth as a human being。
1and every one of those cells knows exactly what to do to preserve and nurture you from themoment of conception to your last breath。
you have no secrets from your cells。 they know far more about you than you do。 each onecarries a copy of the plete genetic code鈥攖he instruction manual for your body鈥攕o itknows not only how to do its job but every other job in the body。 never in your life will youhave to remind a cell to keep an eye on its adenosine triphosphate levels or to find a place forthe extra squirt of folic acid that鈥檚 just unexpectedly turned up。 it will do that for you； andmillions more things besides。
every cell in nature is a thing of wonder。 even the simplest are far beyond the limits ofhuman ingenuity。 to build the most basic yeast cell； for example； you would have tominiaturize about the sam