re based notsimply on their chemistry； as with genes； but also on their shapes。 to function； a protein mustnot only have the necessary chemical ponents； properly assembled； but then must also befolded into an extremely specific shape。 鈥渇olding鈥潯s the term that鈥檚 used； but it鈥檚 amisleading one as it suggests a geometrical tidiness that doesn鈥檛 in fact apply。 proteins loopand coil and crinkle into shapes that are at once extravagant and plex。 they are more likefuriously mangled coat hangers than folded towels。
moreover； proteins are （if i may be permitted to use a handy archaism） the swingers of thebiological world。 depending on mood and metabolic circumstance； they will allowthemselves to be phosphorylated； glycosylated； acetylated； ubiquitinated； farneysylated；sulfated； and linked to glycophosphatidylinositol anchors； among rather a lot else。 often ittakes relatively little to get them going； it appears。 drink a glass of wine； as scientificamerican notes； and you materially alter the number and types of proteins at large in yoursystem。 this is a pleasant feature for drinkers； but not nearly so helpful for geneticists who aretrying to understand what is going on。
it can all begin to seem impossibly plicated； and in some ways itis impossiblyplicated。 but there is an underlying simplicity in all this； too； owing to an equallyelemental underlying unity in the way life works。 all the tiny； deft chemical processes thatanimate cells鈥攖he cooperative efforts of nucleotides； the transcription of dna into rna鈥攅volved just once and have stayed pretty well fixed ever since across the whole of nature。 asthe late french geneticist jacques monod put it； only half in jest： 鈥渁nything that is true of e。
coli must be true of elephants； except more so。鈥�
every living thing is an elaboration on a single original plan。 as humans we are mereincrements鈥攅ach of us a musty archive of adjustments； adaptations； modifications； andprovidential tinkerings stretching back 3。8 billion years。 remarkably； we are even quite closely related to fruit and vegetables。 about half the chemical functions that take place in abanana are fundamentally the same as the chemical functions that take place in you。
it cannot be said too often： all life is one。 that is； and i suspect will forever prove to be； themost profound true statement there is。
part vithe road to usdescended from the apes！ my dear；let us hope that it is not true； but if it is；let us pray that it will not beegenerally known。
…remark attributed to the wife ofthe bishop of worcester afterdarwin鈥檚 theory of evolution was explained to her
w w w。 xiao shuotxt。 co m
27 ICE TIME
灏彙〃t：xt。。澶″爞
i had a dream； which was notall a dream。
the bright sun wasextinguish鈥檇； and the starsdid wander 。 。 。
鈥攂yron； 鈥渄arkness鈥�
in 1815 on the island of sumbawa in indonesia； a handsome and long…quiescent mountainnamed tambora exploded spectacularly； killing a hundred thousand people with its blast andassociated tsunamis。 it was the biggest volcanic explosion in ten thousand years鈥�150 timesthe size of mount st。 helens； equivalent to sixty thousand hiroshima…sized atom bombs。
news didn鈥檛 travel terribly fast in those days。 in london； the times ran a small story鈥攁ctually a letter from a merchant鈥攕even months after the event。 but by this time tambora鈥檚effects were already being felt。 thirty…six cubic miles of smoky ash； dust； and grit haddiffused through the atmosphere； obscuring the sun鈥檚 rays and causing the earth to cool。
sunsets were unusually but blearily colorful； an effect memorably captured by the artist j。 m。
w。 turner； who could not have been happier； but mostly the world existed under anoppressive； dusky pall。 it was this deathly dimness that inspired the byron lines above。
spring never came and summer never warmed： 1816 became known as the year withoutsummer。 crops everywhere failed to grow。 in ireland a famine and associated typhoidepidemic killed sixty…five thousand people。 in new england； the year became popularlyknown as eighteen hundred and froze to death。 morning frosts continued until june andalmost no planted seed would grow。 short of fodder； livestock died or had to be prematurelyslaughtered。 in every way it was a dreadful year鈥攁lmost certainly the worst for farmers inmodern times。 yet globally the temperature fell by only about 1。5 degrees fahrenheit。 earth鈥檚natural thermostat； as scientists would learn； is an exceedingly delicate instrument。
the nineteenth century was already a chilly time。 for two hundred years europe and northamerica in particular had experienced a little ice age； as it has bee known； whichpermitted all kinds of wintry events鈥攆rost fairs on the thames； ice…skating races along dutchcanals鈥攖hat are mostly impossible now。 it was a period； in other words； when frigidity wasmuch on people鈥檚 minds。 so we may perhaps excuse nineteenth…century geologists for beingslow to realize that the world they lived in was in fact balmy pared with former epochs；and that much of the land around them had been shaped by crushing glaciers and cold thatwould wreck even a frost fair。
they knew there was something odd about the past。 the european landscape was litteredwith inexplicable anomalies鈥攖he bones of arctic reindeer in the warm south of france； hugerocks stranded in improbable places鈥攁nd they often came up with inventive but not terribly plausible explanations。 one french naturalist named de luc； trying to explain how graniteboulders had e to rest high up on the limestone flanks of the jura mountains； suggestedthat perhaps they had been shot there by pressed air in caverns； like corks out of apopgun。 the term for a displaced boulder is an erratic； but in the nineteenth century theexpression seemed to apply more often to the theories than to the rocks。
the great british geologist arthur hallam has suggested that if james hutton； the father ofgeology； had visited switzerland； he would have seen at once the significance of the carvedvalleys； the polished striations； the telltale strand lines where rocks had been dumped； and theother abundant clues that point to passing ice sheets。 unfortunately； hutton was not a traveler。
but even with nothing better at his disposal than secondhand accounts； hutton rejected out ofhand the idea that huge boulders had been carried three thousand feet up mountainsides byfloods鈥攁ll the water in the world won鈥檛 make a boulder float； he pointed out鈥攁nd becameone of the first to argue for widespread glaciation。 unfortunately his ideas escaped notice； andfor another half century most naturalists continued to insist that the gouges on rocks could beattributed to passing carts or even the scrape of hobnailed boots。
local peasants； uncontaminated by scientific orthodoxy； knew better； however。 thenaturalist jean de charpentier told the story of how in 1834 he was walking along a countrylane with a swiss woodcutter when they got to talking about the rocks along the roadside。 thewoodcutter matter…of…factly told him that the boulders had e from the grimsel； a zone ofgranite some distance away。 鈥渨hen i asked him how he thought that these stones had reachedtheir location； he answered without hesitation： 鈥榯he grimsel glacier transported them on bothsides of the valley； because that glacier extended in the past as far as the town of bern。鈥櫋♀��
charpentier was delighted。 he had e to such a view himself； but when he raised thenotion at scientific gatherings； it was dismissed。 one of charpentier鈥檚 closest friends wasanother swiss naturalist； louis agassiz； who after some initial skepticism came to embrace；and eventually all but appropriate； the theory。
agassiz had studied under cuvier in paris and now held the post of professor of naturalhistory at the college of neuchatel in switzerland。 another friend of agassiz鈥檚； a botanistnamed karl schimper； was actually the first to coin the term ice age （in german eiszeit ）； in1837； and to propose that there was good evidence to show that ice had once lain heavilyacross not just the swiss alps； but over much of europe； asia； and north america。 it was aradical notion。 he lent agassiz his notes鈥攖hen came very much to regret it as agassizincreasingly got the credit for what schimper felt； with some legitimacy； was his theory。
charpentier likewise ended up a bitter enemy of his old friend。 alexander von humboldt； yetanother friend； may have had agassiz at least partly in mind when he observed that there arethree stages in scientific discovery： first； people deny that it is true； then they deny that it isimportant； finally they credit the wrong person。
at all events； agassiz made the field his own。 in his quest to understand the dynamics ofglaciation； he went everywhere鈥攄eep into dangerous crevasses and up to the summits of thecraggiest alpine peaks； often apparently unaware that he and his team were the first to climbthem。 nearly everywhere agassiz encountered an unyielding reluctance to accept his theories。
humboldt urged him to return to his area of real expertise； fossil fish； and give up this madobsession with ice； but agassiz was a man possessed by an idea。
agassiz鈥檚 theory found even less support in britain； where most naturalists had never seena glacier and often couldn鈥檛 grasp the crushing forces that ice in bulk exerts。 鈥渃ould scratches and polish just be due to ice ？鈥潯sked roderick murchison in a mocking tone at one meeting；evidently imagining the rocks as covered in a kind of light and glassy rime。 to his dying day；he expressed the frankest incredulity at those 鈥渋ce…mad鈥潯eologists who believed that glacierscould account for so much。 william hopkins； a cambridge professor and leading member ofthe geological society； endorsed this view； arguing that the notion that ice could transportboulders presented 鈥渟uch obvious mechanical absurdities鈥潯s to make it unworthy of thesociety鈥檚 attention。
undaunted； agassiz traveled tirelessly to promote his theory。 in 1840 he read a paper to ameeting of the british association for the advancement of science in glasgow at which hewas openly criticized by the great charles lyell。 the following year the geological society ofedinburgh passed