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智科眼: 双语看懂新世界
演化 655
A(一个) few(few) years() ago(),(,) Scott(斯科特) Villa(维拉) of(of) Emory(埃默里) University(大学) had() a(a) problem(问题).(.) Then(然后) a(一个) graduate(研究生) student() at(at) the University(大学) of(of) Utah(犹他),(,) he() was() stumped(难倒) with(with) an(一个) issue(问题) never(遇到) addressed(解决) in(in) school(学校):(:) How(如何) does(does) one(one) film(电影) lice(虱子) having() sex()?(?)
Villa(别墅) and() University(大学) of(of) Utah(犹他) biologists(生物学家) had(had) demonstrated(展示) real-time(实时) adaptation(适应性) in(in) their(他们) lab(实验室) that(that) triggered(触发) reproductive isolation(生殖隔离) in(in) just(just) four() years(年内),(,) mimicking(模仿) millions(百万) of(of) years() of(of) evolution(进化).(.) They(它们) began(开始) with(with) a(a) single() population(种群) of(of) parasitic(寄生) feather(羽毛) lice(),(,) split(分成) the population(群体) in(in) two(two) and() transferred(转移) them(他们) onto(onto) different(不同)-()sized(大小) hosts(宿主)()pigeons(鸽子) with(with) small() feathers(羽毛),(,) and() pigeons(鸽子) with(with) large() feathers(羽毛).(.) The pigeons(鸽子) preened(梳妆打扮) at(at) the lice(虱子) and() populations(种群) adapted(适应) quickly(迅速) by(通过) evolving(不断变化) differences(差异) in(in) body() size().(.) After(经过) 60(60) generations(),(,) the biologists(生物学家) saw(看到) larger(更大) lice(虱子) on(on) larger() pigeons(鸽子) and() smaller(较小) lice(虱子) on(on) smaller(较小) pigeons(鸽子).(.) When(When) they(他们) paired(配对) the different(不同)-()sized(大小) male(雄性) and() female(雌性) lice(虱子) together(一起),(,) the females(雌性) laid() zero() eggs().(.) The divergent(不同) body() sizes(尺寸) were(were) likely(可能) preventing(阻止) the lice(虱子) from(from) physically(物理) mating(交配) with(with) each(相互) other(other),(,) which(which) demonstrates(证明) the beginning(起始) stages(阶段) of(of) a(a) new() species(物种).(.)
But() the researchers(研究人员) needed(需要) to(to) know(知道) for(for) sure(确切).(.) They(他们) put(放在) the lice(虱子) on(on) a(a) plate() of(of) pigeon(鸽子) feathers(羽毛) to(to) set(设定) the mood(心情),(,) primed(准备) the camera(相机) and() waited(等待).(.) But() the lice(虱子) had() stage(阶段) fright(怯场).(.)
"(")There() was(was) a(a) lot(很多) of(of) trial(试验) and() error(错误).(.) No(没有) one(one) has(has) filmed(拍过) lice(虱子) mating(交配) before(以前),(,) I(I) guarantee(保证) you() that(that),"(,") said() Villa(维拉).(.)
They(他们) were(were) flummoxed(困惑) until(直到) an(一个) undergraduate(本科) researcher(研究员) brought() a(a) heating(加热) pad() into(into) the lab(实验室) for(for) her() sore() back().(.) It() gave(给了) Villa(别墅) an(一个) idea(想法).(.) Turns(事实证明) out(out) that(that) for(for) feather(羽毛) lice(虱子),(,) a(a) hot() pad() tuned(调整) to(to) a(a) bird(鸟类)'s('s) core temperature(核心温度) is() where(where) the magic(神奇) happens(发生).(.)
"(")What(What) we(我们) saw(看到) was() amazing(惊人),(,) the male(雄性) lice(虱子) physically(物理) could(可能) not() mate() with(with) the females(雌性),(,) so(因此) we(我们) think(认为) this() is() how(how) new() species(物种) start(开始) to(to) form(形成),"(,") said() Villa(别墅).(.) "We("We) already(已经) knew(知道) that(that) in(in) the wild(),(,) larger() species(种类) of(of) birds(鸟类) have() larger() species(种类) of(of) lice(虱子).(.) What(What) we(我们) didn(didn)'t('t) know(知道),(,) and(以及) what(what) came() out(out) of(of) this(这项) study(研究),(,) is() that(that) because of(由于) the way(方式) that(that) the lice(虱子) mate(),(,) adapting(适应) to(to) a(a) new() host(宿主) by(通过) changing(改变) size(大小) has(具有) this() massive(巨大) automatic(自动) effect(效应) on(on) reproduction(繁殖)."(.")
The study(研究) experimentally(实验) demonstrates(证明) ecological(生态) speciation(物种形成),(,) a(a) concept(概念) first(首先) championed(拥护) by(by) Charles(查尔) Darwin(达尔文).(.) Different(不同) populations(种群) of(of) the same(同一) species(物种) locally(在当地) adapt(适应) to(to) their() environments(环境),(,) and() those(这些) adaptations(适应性) can() cause(导致) reproductive isolation(生殖隔离) and() eventually(最终),(,) lead to(导致) the origin(起源) of(of) a(a) new() species(物种).(.)
"(")People(人们) study(研究) this(这种) in(in) all(各种) sorts() of(of) systems(系统中),(,) everything() from() fruit flies(果蝇) to(to) stickleback() fish() to(to) walking(拐杖) sticks().(.) But() they(它们) are() always() taking(采取) recently(最近) evolved() species(物种) or() populations(种群) that() have(具有) already(已经) diverged() and() trying() to(to) understand(理解) why(为什么) they(他们)'re('re) no() longer() reproductively(生殖) compatible(兼容),"(,") said() Dale(戴尔) Clayton(克莱顿),(,) professor(教授) of(of) biology(生物学) and() co-(共同)author(作者) of(of) the study(研究).(.) "(")Very() few(few) have() taken(采用) a(一种) single() population(种群) and() evolved(进化) it() under(under) natural conditions(自然条件) into(into) two(两种) different(不同) populations() that(that) cannot(不能) reproduce(繁殖).(.) That(That)'s('s) the new(新的) piece(部分) of(of) this()."(.")
The paper(论文) was(was) published(发表) in(in) the Proceedings() of(of) the National(国家) Academy(科学院) of(of) Sciences(科学) of(of) the United() States() of(of) America() on(on) June(6月) 10,(10,) 2019.(2019.)
The sweet(甜蜜) spot()
Different(不同)-()sized(大小) pigeons(鸽子) have() different(不同)-()sized(大小) lice(虱子);(;) in(in) most(大多数) cases(情况),(,) the bigger() the pigeon(鸽子),(,) the bigger() their(它们) lice(虱子).(.) In(In) 1999,(1999,) Clayton(克莱顿) led(领导) a(一项) study(研究) that(that) found(发现) that(that) birds(鸟类)'(') preening(整理) drives(推动) this(这种) pattern(模式).(.)
Feathers(羽毛) consist(组成) of(of) ridges(),(,) called(称为) barbs(倒钩),(,) that(that) create(创建) tiny() gaps(间隙) known as(被称为) the interbarb(条间) space(空间).(.) It's(It's) the pigeon(鸽子)'s('s) blind spot(盲点)()lice() wedge(楔子) in(in) their(他们) long(),(,) slender() bodies(身体) to(to) escape(逃脱) deadly(致命) beaks().(.) When(When) big() lice(虱子) crawl(爬行) on(on) smaller(较小) feathers(羽毛),(,) they(它们) stick(坚持) out(out) of(of) the space(空间) and() birds() pick(捡起) them(它们) off(off).(.) So(所以) it's(it's) good() to(to) be(be) small(),(,) right()?(?) Not quite(不完全).(.) In(In) 2018,(2018,) this() same(同一) research(研究) group(小组) found(发现) that(that) bigger(更大) female(雌性) lice(虱子) lay() more(更多) eggs().(.) Evolutionary(进化) winners(赢家) fall() into(into) a(一个) sweet(甜蜜) spot(地方)()they(它们)'re('re) just(只是) small() enough(足以) to(to) squeeze() into(into) the interbarb(interbarb) space(空间),(,) but() big() enough(足够) to(to) outbreed(异种繁殖) smaller() neighbors(邻居).(.)
"(")There()'s('s) constant(常数) selective pressure(选择压力) to(to) be(be) as(as) big() as(as) possible(可能) to(to) pump() out(out) as(as) many() eggs(鸡蛋) as(as) possible(可能).(.) But(但是) preening(整理) puts(提出) the breaks(休息) on(on) getting() too() big().(.) There()'s('s) a(一个) sweet(甜蜜) spot(地方),"(,") said() Villa(维拉).(.) "If("If) you() put(放在) lice(虱子) on(on) different(不同) sized(大小) birds(鸟类),(,) the sweet(甜蜜) spot() shifts() and() the lice(虱子) evolve(发展) optimal(最佳) body() sizes(形成) after(经过) a(a) few(few) generations(发生)."(.")
The experimental(实验性) change(变化) in(in) size(大小) is() heritable(可遗传)() the biologists(生物学家) showed(表明) that(that) big() parents(父母) had() big() offspring(后代) and() small() parents(父母) had() small() offspring(后代),(,) regardless(无论) of(of) the size(大小) of(of) the birds() on(on) which(which) they(他们) were(were) mating(交配).(.)
The parasitic(寄生) lice() populations(群体) adapted(适应) quickly(迅速).(.) "(")Significant(显着) size(尺寸) differences(差异) appeared(出现了) after(after) just(仅仅) 18(18) months(),"(,") said() co-(共同)author(作者) Sarah(萨拉) Bush(布什),(,) associate professor(副教授) of(of) biology(生物学) at(at) the U.(U.) This(这种) pattern(模式) informs(告诉) more(more) than(than) just(仅仅) this(这个) system(系统).(.)
"(")The idea(想法) is() that(that) bigger(更大) hosts(宿主) have() bigger(更大) parasites(寄生虫).(.) That(That)'s('s) true() for(for) trees(树木) with(with) parasitic(寄生) insects(昆虫),(,) for(for) fleas(跳蚤) on(on) animals(动物),(,) for(for) ticks(蜱虫) on(on) mammals(哺乳动物)—it's(—it's) true(真正) for(for) life(生命),"(,") Bush(布什) continued(继续).(.) "It's("It's) a(一个) bigger(更重) question(问题) than(than) just(just) this() one(one) particular(特定) system(系统).(.) It() happens(发生) everywhere(到处).(.) Part(部分) of(of) what(what) we're(we're) doing() is() trying() to(to) figure() out(out) that(that) pattern(模式)."(.")
Lice(虱子),(,) camera(相机),(,) no(no) action(动作)!(!)
The researchers(研究人员) are() the first(第一个) to(to) capture(捕捉) how(how) feather(羽毛) lice(虱子) mate().(.) By(通过) understanding(了解) the mechanics(机制) of(of) lice(虱子) sex(),(,) they(他们) saw(看到) what(什么) works(有效),(,) and() what(什么) fails(失败).(.) In(In) short(简短)()size(大小) matters(事情).(.)
Female(雌性) lice(虱子) are(are) naturally(自然) about(大约) 13%(13%) bigger(更大) than(than) male(雄性) lice(虱子).(.) This(这种) dimorphism(二态性) between(between) the two(two) sexes(两性) is() critical(至关重要) for(for) reproduction(繁殖).(.) Males(雄性) have() thick() antenna(天线) to(to) cling() to(to) females(女性) during(during) copulation(交配).(.) They(他们) approach(接近) the female(女性) from() behind(后面),(,) slide(滑动) underneath() her() and() curl(卷曲) the tip(尖端) of(of) their(它们) abdomen(腹部) while() holding(抱着) her() thorax(胸部).(.) If(如果) the male(男性) is(is) too() small(),(,) he() may(可能) struggle(很难) to(to) reach() the female(女性) where(where) he(he) needs(需要) to.(to.) If(如果) he's(he's) too() large(),(,) he'll(he'll) overshoot(会超) the female(女性).(.) That(That)'s('s) exactly(正是) what(what) the researchers(研究人员) saw(看到).(.)
"(")There()'s('s) a(一个) Goldilocks(金发姑娘) Zone().(.) The males(男性) and() females(女性) have to(必须) be(be) just(just) the right(适合) size(大小) for(for) each other(彼此).(.) Pairs(配对) of(of) lice(虱子) where(where) dimorphism(异形) falls() outside() of(of) that() zone(区域) suffer(遭受) massive(巨大) reproductive(生殖) consequences(后果),"(,") said() Villa(维拉).(.)
They(他们) found(发现) that(that) typically(通常) sized(大小) lice(虱子) copulated(交配) the longest(最长) and() laid() the most() eggs().(.) Pairs(配对) of(of) lice(虱子) with(with) dimorphism(二态性) outside(以外) of(of) the Goldilocks(金发姑娘) Zone() copulated(交配) for(for) shorter() amounts(数量) of(of) time(时间) and(并且) laid() zero() eggs().(.) They(它们) think(认为) this() is() because(因为) males(雄性) either(either) physically(身体) fail(不能) to(to) inseminate(受精) the females(雌性),(,) or(or) they(他们) can()'t('t) copulate(交配) long() enough(足够) to(to) fertilize(受精) her(her) eggs(卵子).(.) Their(他们) experiments(实验) tested(测试) this() with(with) lice(虱子) on(on) feathers(羽毛) and() a(a) heat() pad() on(on) camera(相机),(,) and(以及) on(on) pigeons(鸽子) themselves(本身).(.) The results(结果) were() the same(相同)()pairs() with(with) sizes(大小) in(in) the Goldilocks(金发姑娘) Zone() had(had) the most() offspring(后代).(.)
The researchers(研究人员) think(认为) that(that) the lice(虱子) populations(群体) evolved(进化) reproductive isolation(生殖隔离) so(非常) quickly() because(因为) body() size(大小) is() a(一种) '(')magic(神奇)'(') trait(特征) that(that) is(is) essential(至关重要) for(for) both(both) survival(生存) and() reproduction(繁殖).(.) If(如果) there(存在)'s('s) a(a) selective(选择性) pressure(压力) on(on) survival(生存),(,) such as(例如) preening(整理),(,) then(那么) reproductive isolation(生殖隔离) will() automatically(自动) follow(跟随).(.)
"(")The idea(想法) of(of) a(a) single(单一) trait(特征) governing(控制) both(both) survival(生存) and() reproduction(繁殖) has(has) been(been) known() for(for) some() time(时间).(.) However(然而),(,) pinning(确定) down(down) how(如何) these(这些) multipurpose(多功能) traits(特性) actually(实际) drive(推动) speciation(物种形成) has(具有) been(been) challenging(挑战性).(.) What(What) makes() this() paper(论文) so(如此) interesting(有趣) is(is) that(that) we(我们) actually(实际上) identified(确定) how(如何) these(这些) "(")magic(魔法) traits(特征)"(") work(工作) in(in) real time(实时).(.) And() just as(正如) theory(理论) predicts(预测),(,) selection(选择) on(on) these(这些) traits(特征) can(可以) generate(产生) reproductive isolation(生殖隔离) in(in) the evolutionary(进化) blink(眨眼) of(of) an(an) eye(眼睛).(.) Our(我们) study(研究) complements(补充) a lot of(许多) fantastic(奇妙<

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