解开古老谜题:鸟类是如何飞行的?(上)

This is Scientific American’s 60-Second Science, I'm Emily Schwing.

这里是科学美国人——60秒科学系列，我是艾米莉·施温。

Have you ever looked up to see a hawk soar overhead, or a small chickadee flit by and wondered: How do they do that?

你是否曾经抬头看到一只老鹰在头顶翱翔，或看到一只小山雀飞过，然后想:它们是怎么做到的?

Believe it or not, scientists never really knew either?—until now.

信不信由你，科学家们也从未真正知道它们是怎么做到的? 直到现在。

I looked at the relationship between form and function in the most basic sense.

我研究了形式和功能之间的最基本的关系。

Talia Lowi-Merri is a Ph.D. student at the University of Toronto in Canada.

塔里亚·洛伊·梅里是加拿大多伦多大学的一名博士生。

She says bird flight has everything to do with the shape and size of a bird’s sternum, or breastbone.

她表示，鸟的飞行与鸟胸骨的形状和大小有很大关系。

Bird sternums have a projection from the middle called the keel, and this is where the flight muscles are attached.

鸟的胸骨中间有一个隆起的部分，叫做龙骨突，这是飞行肌肉附着的地方。

It's plausible to think that this element is important for flight.

认为这个基本部位对飞行很重要是有道理的。

But why does it vary so much in shape and size relative to the body?

但是为什么龙骨突的形状和大小相对于身体有这么大的差异呢?

There are all these questions about it that haven't been answered in the past.

关于龙骨突，有很多问题在过去都没有得到解答。

So, Merri set out to find some answers using a database of CT scanned sternums from 105 different bird species, like the Red-capped lark, Leach’s Storm petrel and the Southern cassowary.

因此，梅里开始利用105种不同鸟类的胸骨CT扫描数据库来寻找答案，这些鸟类包括红顶短趾百灵、白腰叉尾海燕和双垂鹤鸵。

She also included two extinct birds: the Dodo and the Great auk.

还包括两种灭绝的鸟类:渡渡鸟和大海雀。

The scans combine a series of x-rays to create three dimensional images.

这种扫描结合一系列的X射线来创建三维图像。

There have been newer technologies come out recently to look at shape in three dimensions.

最近出现了一些新的技术来观察三维的形状。

And so because the sternum is a complex element in three dimensions.

因为胸骨是一个复杂的三维结构。

It's not just a 2-D bone. It's got projections about the middle and its sides.

它不只是一个二维的骨头。它的中间和两边都有凸起。

Looking at it in three dimensions is the best way to quantify the shape and analyze it in a statistical framework.

从三维角度观察是量化形状并在统计框架中分析它的最好方法。

So more recently, those methods have become more accessible.

所以最近，这些方法变得更容易使用。

And I guess because of that, I was able to do it now and maybe 10 or 15 years ago, it wasn't possible.

我想正因为如此，我现在能够做到这一点，而在10或15年前，这是不可能的。

Merri and colleagues used the scans to create computerized 3D models.

梅里和他的同事们利用这些扫描来创建计算机化的3D模型。

And so when you do that, you can move it around.

当你这样做的时候，你可以移动它。

You can place points on it in the important spots.

你可以在重要的地方放置点。

And so that's what I was doing.

这就是我所做的。

I was putting these dots that are called landmarks, and the landmarks basically quantify in 3-D computer space where the important points are on the element.

我放置的这些点称为地标，地标基本上在三维计算机空间中是量化的，在空间中，重要的点放置在基本部位。

The findings, published in BMC Biology, show that sternum size and shape has a direct impact on the way a bird flies.

这项研究结果发表在《BMC生物学》杂志上，研究表明胸骨的大小和形状对鸟的飞行方式有直接影响。

So an eagle would be soaring and wouldn't be moving its wings as much.

老鹰在翱翔时不会频繁地挥动翅膀。

It just has its arms stretched out, and it has very intricate structures in its wings and at its shoulder to hold the wings out, but it doesn't have to use as much flapping power.

老鹰只是伸展翅膀，它的翅膀和肩膀上有非常复杂的结构来支撑翅膀飞行，但它不需要使用太多的拍打力。