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Evolution has given us some useful abilities.
进化赋予了我们许多实用的能力
Over the past millions of years, we've evolved to stand on two legs, use tools, and develop language.
在过去的上百万年 我们已经进化出双腿站立 使用工具和发明语言的能力
And as recently as a few thousand years ago, humans were still evolving.
而且在近几千年前 人类还在不断进化
Part of what drives evolution is natural selection —
自然选择是推动进化的驱动力之一
where those with traits that make them better adapted to their environment
即具有某些能够更好地适应环境特性的物种
tend to survive long enough to pass on those traits to their offspring.
趋于获得更长的寿命并使这种特性遗传给他们的后代
Modern medicine can sometimes interfere with that process, since it keeps people alive who maybe otherwise wouldn’t be.
现代医学有时候会干扰这个过程 因为它使一些可能会死去的人继续活下去
But that doesn't mean humans are done evolving.
但是这并不代表人类已完成进化
One recent example of human evolution is the fact that 35% of adult humans can digest milk.
举一个最近的人类进化史上的例子来说 有35%的成年人可以消化牛奶
7,000 years ago, not nearly as many people could to do that.
但是7000年前 能消化牛奶的人却没有这么多
Instead, mainly babies drank and digested milk, so they could get energy from the lactose in their mother's breast milk.
反而大多数婴儿都能够摄取并消化牛奶 使他们可以从母乳中 摄取乳糖和其能量
Once they grew up though, the gene that allowed them to digest milk was swiched off
然而当他们一长大 允许消化牛奶的基因就会停止工作
But when we domesticated cattle, the mutation that allowed certain people to digest milk
但当我们圈养奶牛时 某些可以因为基因突变可以消化牛奶
as adults became something that helped them survive, since they had an extra source of nutrition.
的成年人变得更容易生存 因为他们能获得更多的营养
A few thousand years later, being able to digest lactose is pretty normal.
几千年之后 能够消化乳糖已经变得很平常
So, humans were still evolving in the not-so-distant past.
所以 人类在近代依旧在进化
And a lot of scientists think that we still are —and we might even be able to predict what future humans will be like.
许多科学家认为我们仍在进化 并且我们甚至能够预测未来人类是什么样子的
For one thing, it's possible that in the future, women will be shorter and slightly heavier than they are now.
比如 未来的女性将会比现在更矮和稍微更胖一些
Researchers figured this out using the data from the Framingham Heart Study,
得出这个结论的研究采用了佛雷明汉心脏研究的数据
which tracks the medical histories of more than 14,000 people who live in Framingham, Massachusetts.
这份数据追踪了14000位住在马萨诸塞州的傅雷明汉的人的医疗历史
The team wanted to know what traits gave women higher reproductive success.
研究团队希望知道哪些特性使女性更容易生孩子
They found that shorter, slightly heavier women tended to have more children --
他们发现 矮的和微胖的女性有更多的孩子--
and those traits were passed on to their children.
这些特性也遗传给了她们的孩子
If this trend continues, in ten generations the average woman might be about 2 centimeters shorter and a kilogram heavier.
照这个趋势下去 10代之后女性的平均身高会减少2厘米 平均体重增加1Kg
Another possible difference between us and future humans is that their brains might be a bit smaller.
另一个未来和现在可能的区别是人类的大脑可能会变得更小一些
Which is weird, because for most of human history, brain sizes tended to get bigger over time
听起来很怪 因为从人类历史来说 人类的大脑一直趋向于变得更大
But over the past 20,000 years, the brain size of homo sapiens has decreased.
但是在过去2万年 智人的大脑变小了
During that time, the average volume of the male brain has shrunk from about 1,500 cubic
在此期间 男性的大脑容量从1500立方厘米
centimeters to about 1,350 -- about a tennis-ball-sized difference.
缩减到1350 -- 有一个网球的大小
A similar decrease in brain size happened for women, too. But why the change?
女性的大脑体积也轻微地减小了 但这是为什么呢？
One possibility is that our brains are smaller thanks to the emergence of more complex societies.
一个可能性是我们的大脑变小了是因为更多复杂的社会群体的出现
As population density increased, and there was more division of labor,
随着人口密度增加 劳动力划分更仔细
humans didn't have to be as smart to stay alive, so their brains didn't have to be as big.
人类生存不需要很聪明 所以大脑不需要那么大
Other scientists think our brains have been shrinking because we've become more tame.
其他的科学家认为我们的大脑变小是因为我们变得更温顺了
See, domesticated animals have smaller brains than their wild counterparts --
看 家养动物比起野生的同种动物大脑会更小 --
probably because if a wild animal isn't smart enough, it won't survive too long.
这或许是因为 野生动物如果不够精明，就不容易生存下去
So, like domesticated animals, maybe our brains have gotten smaller because we aren't constantly
所以 像家养动物一样 我们的大脑没有变得更聪明因为我们不需要一直
worried about things like being attacked by predators.
担心事情比如受到捕食者的攻击
But a shrinking brain also might not mean that the human species is getting dumber --
但是缩小的大脑并不代表了人类变得更愚蠢 --
instead, our brains might just be getting more efficient.
相反 我们的大脑可能变得更有效率了
Having a big brain uses up a lot of energy, so if it's a little smaller and more efficient,
一个大的大脑需要更多能量 所以当它变小和高效时
we don't need as much energy to stay alive.
我们不需要用很多能量来维持生命
That said, a recent study of the skulls of Americans showed that they've actually been getting bigger since the mid-1800s.
美国人最近一项关于头骨的研究表示人的头骨自19世纪初的中期开始 就不断变大
But that's probably because of better nutrition and not an evolutionary change.
但是这可能是因为更好的营养并不是因为进化改变
So if we factor out the effect of better nutrition, it's possible that the shrinking trend will continue in the future.
所以如果我们排除更好的营养的因素 头骨缩小的趋势将会 持续下去
Even if natural selection isn't what drives the future evolution of our species,
即使自然选择不能驱使我们在未来进化
we might artificially evolve ourselves through genetic engineering.
我们也可以利用基因工程人工进化
As we learn more about what all of our genes do and how to modify them,
只要我们知道了所有的基因的能力和如何修改它们
we'll be able to eliminate certain genetic disorders and maybe even diseases related to getting older.
我们就能够 消除变老产生的特定的基因紊乱和疾病
And eventually, we might be able to design people like we design avatars in video games--
最终 我们或许能够像视频游戏里创建角色一样设计人类--
altering things like height, intelligence, athleticism or any other trait.
调整身高、智力、体能和其他特性
So, whether the changes are natural or artificial, humans of the future might be very different.
所以 不管改变是自然的还是人工的 未来的人类会变得非常不一样
Thanks for watching this episode of SciShow, which was brought to you by our patrons on
感谢观看这一集赞助的SciShow
If you want to help to support the show, just go to patreon.com/scishow
如果你想帮助资助这个节目 去patreon.com/scishow
And don't forget to go to youtube.com/scishow and subscribe!
别忘了去youtube.com/scishow和订阅
