生命的进化（1979）

or on what insect it relies to carry its pollen.
这种兰花用扮演异性的办法吸引昆虫
This orchid attracts insects by sexual impersonation.
它散发出一种类似雌性黄蜂的气味
It gives off a perfume like that of a female ichneumon wasp.
当雄姬蜂接近时，他会发现一些 闻起来和看起来都象雌姬蜂的东西
When the male arrives, he finds something that smells and looks like a female.
在花的末端，一大块花粉聚集在一起 形成一个马蹄的形状
At one end of the bloom, there's a mass of pollen stuck together into a horseshoe shape.
雄姬蜂和花朵交♥配♥
The ichneumon male copulates with the flower.
那些花粉块放置地如此恰当 以至于它们巧妙地沾到了姬蜂的腹部上
And the pollen mass is so placed that it fastens neatly onto his abdomen.
事实上，这种兰花完全依靠这种姬蜂
In fact, this orchid is totally dependent on one species of ichneumon wasp for pollination
授粉和繁殖
and therefore reproduction.
它生存的时间会和这种姬蜂一样长
The orchid can only survive as long as the ichneumon wasps do.
当雄性昆虫和下一朵花交♥配♥时 它从上一朵花那里带来了花粉
When the male insect copulates with the next flower, he delivers the pollen from the last.
中美洲地区的丝兰
The yucca plant of Central America
拥有和其昆虫伙伴如此紧密的关系
has a relationship with its insect partner that is so close
以至于无论是它还是它的昆虫伙伴 都完全依赖于对方
that now both insect and plant are completely dependent on one another.
丝兰的淡黄色的花的来访者是微型蛾
The yucca's creamy blossoms are visited by tiny moths.
白天，这种蛾花很多时间 穿梭于花与花之间来观察花
During the day, the moths spend a lot of time moving from flower to flower and inspecting them.
所有的花都不在同一发展阶段
All are not at the same stage of development.
雄蕊先成熟然后裂开， 蛾所找的就是这个
The stamens become mature first and split open, and it's these that the moth is looking for.
傍晚，已经交♥配♥了的雌蛾
In the late afternoon, the female moth, having already mated,
开始从合适的花上收集花粉
is collecting pollen from suitable flowers.
现在，她正在收集花粉，形成一个硬球
She's now gathered the pollen into a tight ball
她把球放在头下
which she holds under her head as she searches
在寻找其他处于不同发展阶段的花
for other flowers which are in a different state of development.
这次她对花朵的中间部分更感兴趣
This time, she's more interested in the central part of the flower,
找了在其中一个子房♥旁边的位置， 子房♥上有一个绿色的尖柱头
and takes up a position alongside one of the ovaries, which have a green-tipped stigma.
她将在这里呆大概20分钟
Here she will stay for about 20 minutes.
她的输卵管深入到花的子房♥的底部
Her egg-laying tube is deep at the bottom of the flower's ovary,
并且把自己的卵产在了那里
and she's laying her own eggs there.
产完卵，她把花粉粒和她收集的花粉球分开
Having finished laying, she separates pollen grains from the ball she's collected
用为此而特殊进化的口器把它们涂到柱头上
and smears them into the stigma with mouth parts specially developed for the purpose.
现在她将在这朵花的其他子房♥上重复整个过程
Now she will repeat the entire procedure in other ovaries of the flower.
再次产虫卵
The egg-laying position again.
再次给花授粉
Again she will pollinate the flower.
首先她从带着的球中取走一小部分花粉
First she removes a small amount of pollen from the ball she's holding.
通过给花授粉， 她服务的不仅是丝兰而且是她自己的后代
By pollinating the flower, she serves not only the yucca but her own offspring,
由于她确保了下面子房♥里的卵的生长
for she ensures the eggs in the ovary below will develop
这样她的幼虫孵化出来的时候 会有一个马上到手的丰富的食物来源
so that her caterpillars when they hatch will have a rich source of food immediately to hand.
但是幼虫不会吃掉所有的种子
But the caterpillars won't eat all the seeds.
成年蛾不会产那么多的卵 所以当丝兰花结出果实时
The moths don't lay as many eggs as that. So when the yucca comes into fruit,
会有充足的完好的种子来确保长出新的植物
there are plenty of undamaged seeds to ensure that new plants will appear.
但是，这种平衡很脆弱
But the balance is a very delicate one.
如果出现了错误， 对植物和昆虫来讲都将是灾难性的
If it went wrong, it could be disastrous for both plants and insect.
没有蛾，丝兰将不会被授粉
Without the moth, the yucca would not be pollinated.
没有任何一种其他动物 拥有那样特殊的口器能够把花粉嵌入
Nothing else has those special mouth parts for pressing the pollen into the style.
同样，离开了丝兰蛾的幼虫会饿死
And without the yucca, the moth's caterpillars would starve.
花朵有诱人的气味以及迷人的形状， 这对昆虫来讲如此具有吸引力
The seductive odours and beguiling shapes of flowers are so attractive to insects
以至于它们感到这些是不可抗拒的
that they find them virtually irresistible.
其他昆虫以此作为另一种使自己进化的方式
Other insects turn that to their advantage in a different way.
这朵姜花具有移♥动♥的花瓣
This ginger flower has petals that move.
这对任何昆虫来讲都是非常奢侈的设计
It's one of the most extravagant designs of any insect.
这是一只螳螂， 特殊变形的腿与这种花瓣相匹配
For this, with flaps on its legs that match the petals of the flower, is a mantis.
蝴蝶前来吸食花蜜
The butterfly comes to sip nectar.
螳螂有许多种类 它们都是很好的伪装者
There are many different kinds of mantis, all marvellously camouflaged,
很贪婪的猎手
all voracious hunters.
昆虫的肉有很多汁 但是首先螳螂要对付外面的骨骼
The flesh of an insect is succulent, but first the mantis has to deal with the external skeleton,
含有甲壳素的壳
the shell of chitin.
甲壳素是死的材料，它不会扩张
Chitin is dead material. It won't expand.
这对昆虫是一种限制 同时也有另一方面作用
It's one of the few limitations to the insect body that is otherwise so versatile.
为了长大，所有昆虫都要定期蜕壳
In order to grow, all insects have to shed their skin at regular intervals,
这只臭虫正在准备蜕壳
and this bug is just about to do so.
在旧皮肤的下面形成了一个新的，柔软的皮肤 通过吸收空气使皮肤扩张
A new, soft skin has formed underneath, and by sucking in air and inflating itself,
臭虫在撕裂它的旧皮肤
the bug is cracking its old skin.
一旦获得自♥由♥，臭虫让自己继续膨胀
Once free, the bug inflates itself still further,
展开它柔软皮肤上的皱纹，使自己膨胀
stretching out the crinkles in its soft skin and expanding.
大约一小时后，新的骨骼变得坚硬了
After an hour or so, its new skeleton has hardened.
一个刺叶虫正准备做同样的事情
A spiny leaf insect is just about to do the same trick.
它的旧壳在它上方的树枝上挂着 就它从前的幽灵一样
Its old shell hangs from the branch above it like the ghost of its former self.
但是一只昆虫的身体越复杂
But the more complicated an insect's body,
其蜕壳的过程就越吃力
the more laborious this process of skin shedding becomes.
于是一些昆虫不仅简化了这个过程 而且开♥发♥了不同的食物来源
And some insects not only simplify it but exploit different food sources
通过把生命分成不同的阶段简化这个过程
by leading split lives.
这个从卵里出来的动物最终会变成一只蝴蝶
This creature emerging from the egg will eventually become a butterfly.
但由于是它生命的第一个阶段 它尽量使自己的身体简单化
But for the first part of its life, it will keep its body simple.
毛虫
A caterpillar.
毛虫和吃饭机器没有什么区别
A caterpillar is little more than an eating machine.
这一条毛虫开始了它的生命， 当它想继续吃自己的卵壳时
This one starts its life as it means to go on by eating its eggshell.
毛虫存在的意义就是不断进食
The caterpillar's existence is dedicated to food.
它不打算繁殖，所以不需要生殖器官
It won't breed, so it doesn't need sexual organs.
它没有理由吸引异性， 所以不需要发出任何信♥号♥♥
It has no cause to attract a mate, so it need not send out any signals to one
不需要长出翅膀，飞起来寻找异性
or develop wings so it can fly off and look for one.
它的父母经历了许多麻烦
Its parents have gone to a lot of trouble
来确保它能够及时地随手找到充足的食物
to ensure it finds ample food immediately to hand,
所以它真正需要的一切是一对高效率的颚
so all it really needs is an efficient pair of jaws
以及在颚的后面像袋子一样的可扩张的身体
and, behind them, a bag-like expandable body.
但是如果毛毛虫的身体要扩张 它就不能有坚硬的外部骨骼
But if a caterpillar's body is to expand, it can't have a hard external skeleton.
只能是一张薄的，柔软的皮肤 能够轻易地蜕掉，替换
Just a thin, flexible skin that is easily shed and replaced.
这点使它易受到攻击
And that could leave it vulnerable.
所以毛虫不得不用其他的方式保护自己
So caterpillars have to have other ways of protecting themselves.
有些釆用虚张声势的办法 长着看起来像可怕的眼睛的斑纹
Some do it by bluff, developing markings that look like fearsome eyes.
有些开始时依靠伪装， 如果不起作用的话
Some rely on camouflage initially, and if that doesn't work,
它们也会试着吓唬人
they too try to startle.
一种澳大利亚风蝶的毛虫
The caterpillar of an Australian swallowtail
看起来很像一块反光的鸟粪
looks convincingly like a glistening bird dropping,
如果有任何食肉动物认为那是值得探查的
and if any predator thinks that's worth investigating,
它会突然放出奇特的触角
then it suddenly produces strange antennae.
许多毛虫长出尖部有毒的绒毛
Many caterpillars sprout long hairs tipped with poison
能使人的皮肤产生皮疹，阻止鸟吃它们
that can cause quite a rash on a human skin and put off a lot of birds.
为了确保食肉动物们认为它们是不可口的
To make sure would-be predators are in no doubt they're unpalatable,
毛虫通过艳丽的警戒色展现自己
the caterpillars advertise themselves with bright warning colours.
所以通过能达到的最好的保护
So with the best protection they can muster,
毛虫勤劳地消耗食物，
the caterpillars industriously pack away their food,
蠕动着瘦小的但是很华丽的皮肤， 当需要不断长大时
slipping off their thin but flamboyant skins when a bigger one is required
一直长到需要的大小
until they have grown as much as they need.
然后它们开始准备两次梦幻般的蜕变的第一次
And then they prepare for the first of two highly dramatic transformations.
许多蛾在茧中完成这次蜕变
Many moths make the change in private behind a silken shroud.
它们很努力地吐丝和编织
Industriously, they spin and weave.
这一条添加了小片树皮来伪装茧
This one adds tiny pieces of bark to camouflage the cocoon.
其中一些有毒毛的毛虫在换毛时 把毛脱落到茧里
Some of those that had poisonous bristles shed them in their moult within their cocoons
并且将其编织到茧上 这样就会继续保护它们
and weave them into their wrappings so they will continue to protect them.
现在，一切看起来都很平静
And now, all seems still.
显然，生命暂停了
Life, apparently, is suspended.
但是在里面，正在进行一场深刻的革命
But inside, a profound revolution is taking place.
毛虫的身体正在被分解成一种粘稠的液体
The caterpillar's body is breaking down into a kind of soup.
成群的细胞自从生命 从虫卵里出来的时候开始就一直沉睡
Clusters of cells that have remained dormant since the creature emerged from the egg
现在活跃了，吸收粘稠的液体 重新组建一个新的身体，
now become active, absorbing the soup, multiplying and reassembling a new body
利用组成毛虫努力收集的所有的材料
from all the material that the caterpillar so industriously gathered.
多数蝴蝶毛虫通过茧开始这种不为人知的蜕变
Most butterfly caterpillars embark on this change unscreened by a cocoon.
可是通常是在不显眼的地方 比如贴着树干，或者在树叶下面
Though usually inconspicuously close to a stem or under a leaf.
澳大利亚普通乌鸦毛虫第一次编织丝茧， 在它悬挂的地方
The Australian common crow caterpillar first spins a silk thread, from which it hangs.
在皮肤以下，藏着另一个新的皮肤
Beneath its skin it has secreted a new and different one.
旧的皮肤裂开并脱落， 带走不再有用的坚硬部分，
The old skin splits and rolls off, taking with it the hard parts for which there's no more use,
包括腿上微小的爪和两片颚
the tiny claws from the legs and those hard-worked jaws.
新的皮肤变硬了，几小时内变得像镜子一样
The new skin hardens and in a few hours becomes mirror-like,
反射周围的树叶的影子作为更好的伪装
reflecting the foliage around it for better camouflage.
一只蝴蝶的身体，可能需要几个月来构建， 或者不少于一个星期
The body of a butterfly may take months to rebuild, or as little as a week.
翅膀本来是被压缩并皱在一起， 但是昆虫把血液输进其中
The wings are crumpled bags, but the insect pumps blood into them
翅膀慢慢地伸展开了
and slowly they expand.
翅膀变干变硬了， 这只澳大利亚果园蝴蝶可以飞了
The wings dry and harden, and the Australian orchard butterfly is ready for flight.
现在这些蝴蝶的首要任务是寻找配偶
The primary task now of all these butterflies is to find a mate.
气味被用来从很远的距离发现配偶
Scent is used to locate their mates over long distances,
它们华丽的翅膀可以带着它们寻找