进化——人类创造的生活

Books and Arts -- Book Review

文学与艺术——书评

Evolution -- Creature comforts

进化——生物性舒适

Life as We Made It. By Beth Shapiro.

《我们创造的生活》，作者：贝丝·夏皮罗。

Humans are a force of nature.

人类是自然界的一种力量。

This paradoxical thought is the glue that holds “Life as We Made It” together.

这一矛盾的想法就像胶水，将《我们创造的生活》一书中的内容凝聚在一起。

But it is not the environment-changing effects of human activity on land, sea and air that intrigue Beth Shapiro -- or not directly.

但激发起贝丝·夏皮罗兴趣的并不是人类活动对陆地、海洋和空气这些环境的变化所造成的影响——或者说这些并没有直接激发她。

Instead, she looks at how people have altered living organisms themselves, exerting an evolutionary pressure on other species.

相反，她关注的是人类如何改变生物体本身，从而对其他物种施加进化压力。

If turning aurochs into cattle, wolves into dogs or teosinte into maize sounds like a sideshow compared with transforming the composition of the atmosphere, looting the oceans or destroying the rainforests, consider a few facts.

如果说，与改变大气成分、掠夺海洋或破坏雨林相比，把古代野牛变成家牛、把狼变成狗或者把墨西哥类蜀黍变成玉米这种事听起来无关紧要，请仔细思考几个事实。

The most common species of bird is Gallus gallus, the domestic chicken.

最常见的鸟类是原鸡，一种家养的鸡。

Even excluding people themselves, the biomass of domesticated mammals exceeds that of the wild sort by a factor of 14.

即使不把人类本身算在内，家养哺乳动物的生物量也比野生哺乳动物的生物量高出14倍。

A third of Earth’s dry land (deserts and ice caps included) is devoted either to growing domesticated plants for human consumption or to the nutrition of domestic animals.

地球上三分之一的旱地(包括沙漠和冰盖)要么用于种植供人类食用的驯化植物，要么用于给家畜提供营养。

How this came about, and where it is leading, are Dr Shapiro’s topics.

这是如何发生的，以及它将走向何方，就是夏皮罗博士的主题。

Her day job is as an evolutionary molecular biologist -- a recent field, but one just old enough in 1999, when her research career got going, for lots of the good stuff to have been snaffled already.

她白天的工作是进化分子生物学家——这是一个最近才出现的领域，但也已足够古老，因为在1999年她的研究生涯刚开始的时候，有很多好东西已经被抢走了。

Mammoths, musk oxen, giant sloths, dogs, wolves, horses and even Neanderthals were all jealously guarded by other researchers.

猛犸象、麝牛、巨型树懒、狗、狼、马、甚至尼安德特人，都被其他研究人员小心翼翼地把守着。

But, as her supervisor at Oxford pointed out, no one was studying bison.

但是，正如她在牛津大学的导师所指出的那样，没有人在研究野牛。

Bison, it transpires, offer an excellent insight into human influence on other species’ evolution.

现在看来，野牛为人类对其他物种进化的影响提供了极好的洞见。

They started in Asia but migrated to North America during the last Ice Age.

它们起源于亚洲，但在上一个冰河时期迁徙到了北美。

For 100,000 years they thrived.

它们繁荣生长了10万年。

Then people followed them across Beringia, and the massacre began.

然后，人们跟着它们穿过了白令陆桥，拉开的屠杀的帷幕。

Unlike many other large American mammals, bison were not exterminated by the new arrivals.

与许多其他大型美洲哺乳动物不同的是，野牛并没有因为这些新来者而灭绝。

Instead, they evolved.

相反，他们进化了。

Being large, and thus an easy target, was bad.

体型大就会很容易成为目标，这是不利于生存的。

Being small, and better able to survive in the marginal habitats into which they were driven, was good.

体型小，能够使它们在被驱赶至的边缘栖息地更好地生存，这是有利的。

So evolution shrank them by 30%.

因此进化使它们的体积缩小了30%

Later, a second wave of humans arrived, this time by sea from the east.

后来，第二波人类抵达，这一次他们自东方海上而来。

The diseases they brought, particularly smallpox, ran riot among the human population, permitting an explosion in the bison’s.

他们带来的疾病，尤其是天花，在人类中肆虐，使得野牛的数量激增。

But the newcomers also brought guns, railways and eventually another massacre.

但这些新来者也带来了枪支、铁路，并最终带来了另一场屠杀。

The last chapter of the bison’s story involves a human change of heart.

野牛故事的最后一章谈及人类心意的转变。

Having reduced the species to a handful of individuals (125, Dr Shapiro estimates), Homo sapiens set about saving it -- at another price to its gene pool.

在将该物种减少到为数不多的个体（夏皮罗博士估计为125个）后，智人开始拯救它——代价是污染野牛的基因库。

Most bison today are privately owned and raised for their meat.

如今的大多数野牛都是私人所有的，为了获得野牛肉而饲养它们。

They are selectively bred, not least for docility, and share some cattle genes after crossbreeding that happened a bit over 100 years ago.

人类对野牛进行选择性繁殖，主要是为了培育温顺的个性，并且在100多年前发生的杂交后，野牛也拥有着一些家牛基因。

Even the few remaining “wild” bison are intensively managed and carry cattle genes.

即使是仅存的少数“野生”野牛也被集中管理着，并且携带着家牛的基因。

Shrunk, tamed, crossbred and eaten, are bison now a domesticated species?

缩小、驯养、杂交、被食用，现在的野牛能算是驯化物种了吗？

The answer is ambiguous; but the bison’s tale certainly matches that of other, clearly domesticated organisms, from cattle and sheep to wheat and peanuts.

答案并不明确；但野牛的故事与其他明确的驯化生物的故事——从牛羊到小麦和花生——毫无疑问是一致的。

Turning these (and dozens of similarly modified types of creature) into people, as Dr Shapiro summarises their edible fates, while harnessing others as workhorses, has permitted human domination of Earth.

正如夏皮罗博士所总结的它们被食用的命运那般，用这些生物(以及几十种类似的改良生物)来喂养人类，同时将其他生物驯化为劳力，使得人类得以统治地球。

But it has also unleashed a demon.

但这也释放出了恶魔。

For it is only by continually improving the yield of domesticated species that all those extra mouths can be fed.

因为只有不断提高驯化物种的产量，才能喂饱所有那些额外的嘴。

So far, selective breeding has kept up.

到目前为止，选择性育种还在继续。

But more is now needed.

但现在还需要更多的手段。

Though the engineering of genomes for agricultural purposes has, in the view of many, got off to a rocky start, new techniques can cut to the chase, circumventing the requirement for generations of selective breeding.

尽管在许多人看来，用于农业目的的基因组工程起步并不顺利，但这些新技术可以直接切入关键点，不再需要经历几代的选择性育种来达到目的。

Those same techniques promise other things besides.

除了这些，同样的技术还能带来其他好处。

One is the idea of de-extinction -- the creation of simulacra of organisms that no longer exist, such as mammoths, about which Dr Shapiro has written eloquently in the past.

一个是灭绝动物复活的想法，即创造不再存在的生物的拟像，比如猛犸象，夏皮罗博士过去曾撰文清晰有力地阐述过这一点。

Another is the modification of human beings themselves.

另一个则是人类自身的改造。

That is a big and tortuous topic, and she does not dwell on it.

这是一个庞大又冗杂的话题，对此她没有详述。

But in an age when “technology” has become synonymous with the information kind, it is worth being reminded that other sorts are available.

但是，在这个“技术”已经成为信息的同义词的时代，值得提醒的是，还有其他的方式可用。

And with one of them people can, if they so choose, remake themselves.

只要人们愿意，选择其中的一种，就可以由此重塑自己。