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e； a single bacterium could theoreticallyproduce more offspring in two days than there are protons in the universe。 鈥済iven an adequatesupply of nutrients； a single bacterial cell can generate 280；000 billion individuals in a singleday；鈥潯ccording to the belgian biochemist and nobel laureate christian de duve。 in the sameperiod； a human cell can just about manage a single division。
about once every million divisions； they produce a mutant。 usually this is bad luck for themutant鈥攃hange is always risky for an organism鈥攂ut just occasionally the new bacterium isendowed with some accidental advantage； such as the ability to elude or shrug off an attack ofantibiotics。 with this ability to evolve rapidly goes another； even scarier advantage。 bacteriashare information。 any bacterium can take pieces of genetic coding from any other。
essentially； as margulis and sagan put it； all bacteria swim in a single gene pool。 anyadaptive change that occurs in one area of the bacterial universe can spread to any other。 it鈥檚rather as if a human could go to an insect to get the necessary genetic coding to sprout wingsor walk on ceilings。 it means that from a genetic point of view bacteria have bee a singlesuperorganism鈥攖iny； dispersed； but invincible。
they will live and thrive on almost anything you spill； dribble； or shake loose。 just givethem a little moisture鈥攁s when you run a damp cloth over a counter鈥攁nd they will bloom asif created from nothing。 they will eat wood； the glue in wallpaper； the metals in hardenedpaint。 scientists in australia found microbes known as thiobacillus concretivorans that livedin鈥攊ndeed； could not live without鈥攃oncentrations of sulfuric acid strong enough to dissolvemetal。 a species called micrococcus radiophilus was found living happily in the waste tanksof nuclear reactors； gorging itself on plutonium and whatever else was there。 some bacteriabreak down chemical materials from which； as far as we can tell； they gain no benefit at all。
they have been found living in boiling mud pots and lakes of caustic soda； deep insiderocks； at the bottom of the sea； in hidden pools of icy water in the mcmurdo dry valleys ofantarctica； and seven miles down in the pacific ocean where pressures are more than athousand times greater than at the surface； or equivalent to being squashed beneath fiftyjumbo jets。 some of them seem to be practically indestructible。 deinococcus radiodurans is；according to theeconomist ； 鈥渁lmost immune to radioactivity。鈥潯last its dna with radiation；and the pieces immediately reform 鈥渓ike the scuttling limbs of an undead creature from ahorror movie。鈥�
perhaps the most extraordinary survival yet found was that of a streptococcus bacteriumthat was recovered from the sealed lens of a camera that had stood on the moon for two years。
in short； there are few environments in which bacteria aren鈥檛 prepared to live。 鈥渢hey arefinding now that when they push probes into ocean vents so hot that the probes actually startto melt； there are bacteria even there；鈥潯ictoria bennett told me。
in the 1920s two scientists at the university of chicago； edson bastin and frank greer；announced that they had isolated from oil wells strains of bacteria that had been living at depths of two thousand feet。 the notion was dismissed as fundamentally preposterous鈥攖herewas nothing to live on at two thousand feet鈥攁nd for fifty years it was assumed that theirsamples had been contaminated with surface microbes。 we now know that there are a lot ofmicrobes living deep within the earth； many of which have nothing at all to do with theorganic world。 they eat rocks or； rather； the stuff that鈥檚 in rocks鈥攊ron； sulfur； manganese；and so on。 and they breathe odd things too鈥攊ron； chromium； cobalt； even uranium。 suchprocesses may be instrumental in concentrating gold； copper； and other precious metals； andpossibly deposits of oil and natural gas。 it has even been suggested that their tireless nibblingscreated the earth鈥檚 crust。
some scientists now think that there could be as much as 100 trillion tons of bacteria livingbeneath our feet in what are known as subsurface lithoautotrophic microbial ecosystems鈥攕lime for short。 thomas gold of cornell has estimated that if you took all the bacteria out ofthe earth鈥檚 interior and dumped it on the surface； it would cover the planet to a depth of fivefeet。 if the estimates are correct； there could be more life under the earth than on top of it。
at depth microbes shrink in size and bee extremely sluggish。 the liveliest of them maydivide no more than once a century； some no more than perhaps once in five hundred years。
as the economist has put it： 鈥渢he key to long life； it seems； is not to do too much。鈥潯henthings are really tough； bacteria are prepared to shut down all systems and wait for bettertimes。 in 1997 scientists successfully activated some anthrax spores that had lain dormant foreighty years in a museum display in trondheim； norway。 other microorganisms have leaptback to life after being released from a 118…year…old can of meat and a 166…year…old bottle ofbeer。 in 1996； scientists at the russian academy of science claimed to have revived bacteriafrozen in siberian permafrost for three million years。 but the record claim for durability so faris one made by russell vreeland and colleagues at west chester university in pennsylvaniain 2000； when they announced that they had resuscitated 250…million…year…old bacteria calledbacillus permians that had been trapped in salt deposits two thousand feet underground incarlsbad； new mexico。 if so； this microbe is older than the continents。
the report met with some understandable dubiousness。 many biochemists maintained thatover such a span the microbe鈥檚 ponents would have bee uselessly degraded unless thebacterium roused itself from time to time。 however； if the bacterium did stir occasionallythere was no plausible internal source of energy that could have lasted so long。 the moredoubtful scientists suggested that the sample may have been contaminated； if not during itsretrieval then perhaps while still buried。 in 2001； a team from tel aviv university argued thatb。 permians were almost identical to a strain of modern bacteria； bacillus marismortui； foundin the dead sea。 only two of its genetic sequences differed； and then only slightly。
鈥渁re we to believe；鈥潯he israeli researchers wrote； 鈥渢hat in 250 million years b。 permianshas accumulated the same amount of genetic differences that could be achieved in just 3鈥�7days in the laboratory？鈥潯n reply； vreeland suggested that 鈥渂acteria evolve faster in the labthan they do in the wild。鈥�
maybe。
it is a remarkable fact that well into the space age； most school textbooks divided the worldof the living into just two categories鈥攑lant and animal。 microorganisms hardly featured。
amoebas and similar single…celled organisms were treated as proto…animals and algae as proto…plants。 bacteria were usually lumped in with plants； too； even though everyone knewthey didn鈥檛 belong there。 as far back as the late nineteenth century the german naturalisternst haeckel had suggested that bacteria deserved to be placed in a separate kingdom； whichhe called monera； but the idea didn鈥檛 begin to catch on among biologists until the 1960s andthen only among some of them。 （i note that my trusty american heritage desk dictionaryfrom 1969 doesn鈥檛 recognize the term。）many organisms in the visible world were also poorly served by the traditional division。
fungi； the group that includes mushrooms； molds； mildews； yeasts； and puffballs； were nearlyalways treated as botanical objects； though in fact almost nothing about them鈥攈ow theyreproduce and respire； how they build themselves鈥攎atches anything in the plant world。
structurally they have more in mon with animals in that they build their cells from chitin；a material that gives them their distinctive texture。 the same substance is used to make theshells of insects and the claws of mammals； though it isn鈥檛 nearly so tasty in a stag beetle as ina portobello mushroom。 above all； unlike all plants； fungi don鈥檛 photosynthesize； so theyhave no chlorophyll and thus are not green。 instead they grow directly on their food source；which can be almost anything。 fungi will eat the sulfur off a concrete wall or the decayingmatter between your toes鈥攖wo things no plant will do。 almost the only plantlike quality theyhave is that they root。
even less fortably susceptible to categorization was the peculiar group of organismsformally called myxomycetes but more monly known as slime molds。 the name no doubthas much to do with their obscurity。 an appellation that sounded a little more dynamic鈥斺�渁mbulant self…activating protoplasm；鈥潯ay鈥攁nd less like the stuff you find when you reachdeep into a clogged drain would almost certainly have earned these extraordinary entities amore immediate share of the attention they deserve； for slime molds are； make no mistake；among the most interesting organisms in nature。 when times are good； they exist as one…celled individuals； much like amoebas。 but when conditions grow tough； they crawl to acentral gathering place and bee； almost miraculously； a slug。 the slug is not a