腾空时,重力会把我们往下拉,这个过程产生了大量动能。不过,着地时会立刻减速,失去这种动能。

The question why our earliest ancestors lost their hair when fur would
have been beneficial to them – for keeping warm on cold nights, for
example – was pondered by Charles Darwin, the
famous evolutionist: “No one supposes that the nakedness of the
skin is any direct advantage to man.” He concluded that the
reason hominins lost their hair was sexual selection. In other
words, we prefer our partners to have little hair. But what caused our
ancestors to start losing their hair before this preference set in?

When she is chewing the grass,still listening the sound around the
land.Suddenly,she is turning ears and stop chewing.And then she raise up
her head for few second.The antelope try her best to escape.Because she
realizes the cheetah behind the bush.Also the cheetah cannot let the
prey run away.He is follwowing the antelope.He is stretching his
forearms and showing up his sharp claws to hunt the prey.The antelope
has turned her dirction so that the cheetah fails first attack.The
cheetah cannot give up the hunting,same like the antelope never give up
to escaping.But the antelope is too tired to run.The next second she
becomes the cheetah’s dinner.

In fact, persistence hunting remained in use until 2014, such as with
the San people of the Kalahari Desert.

和地球上其他大的哺乳动物比较,我们人类毛发相对来说比较少,这个明显的事实并不奇怪,知道我们看到动物王国里的最亲密亲属——猩猩和猿,为什么?我们可能会问,当所有其他灵长目动物浑身是毛,而我们进化得几乎无毛?事实上,看起来奇怪,我们缺少毛发正是我们进化成功的一个关键。

皇家88平台 1

事实上,人类的髂胫束(包绕大腿的深筋膜)能够储存的弹性势能是黑猩猩的相似部位阔筋膜的15-20倍。当我们迈步时,富有弹性的筋腱可以将50%的弹性势能转化为动能,使我们更容易前进。如果没有这种额外能量,那么我们需要付出更多努力,才能够前进一步。

人类是地球上出汗最多的灵长目动物。他们有多达500的汗腺,每天产生12L的汗水,正是这种出汗特点,使得我们脱发,让我们能很好的成长。要记住下一次你身边无毛躯干是在健身房!

In Africa grassland,it’s the hottest summer in this year.The ground is
almost burned by the heat.Now survives and waits for the rainfall is the
biggest chanllege for these animals.These are group of antelopes is
migrating to somewhere there are more food and water.The long distance
of migration make them tried and now they need for a rest and eats some
grasses.

而人类独特的适应性就体现在这里。我们的大腿肌腱和肌肉极具弹力,它们可以像弹跳器一样将动能转化为弹性势能,以供之后利用。

最可能解释毛发脱落的假说是大约2到300百万前早期的人类有必要转移到一个更广阔的草原栖息地,他们开始狩猎,在开放的草原上狩猎意味着每天暴露在强阳光下几个小时,处于过热的危险中。毛发遮盖身体使得我们的祖先散热慢,所以,英格兰利物浦摩尔大学的皮特解释说,脱发能使得他们更容易出汗,更容易散热。因此,早期人类可以在中午出去狩猎和觅食。“能够度过整个中午的觅食,寻找配偶或者与敌人战斗,这是一个巨大的优势。”牛津大学的大卫说,“出汗证明你大部分没有毛发对汗腺更有用。”捕猎动物的肉给早期人类大脑提供能量。

Not only the herbivores needs to struggle with the horrible
tempreature,but the carnivores cannot without meat to survive.A hungry
cheetah is staring at his delicious dinner.He is the fastest animal on
land.In few seconds,he can run as fast as a car going on the highway.But
only he has one chance to catch one of them.If he lost,he will die.So he
is hiding in the bush and finding the best of opportunity to take
action.It seems the God want to help the poor cheetah.An antelope is
leaving her group to finding more grasses.She don’t notice the eyes
behind the bush.

威尔士的一个小镇每年都会举办“人马长跑大赛”,由骑马者和跑步者共同参与,赛程约为35公里。虽然骑马者常常胜出,但人类有时也能获胜。

Humans are the sweatiest primates on Earth. They have up to 5 million
sweat glands,which produce about 12 litres of sweat per day. It’s
this propensity to sweat that accounts for our hairlessness and has
allowed us to thrive. It might help to remember this next time you’re
surrounded by sweaty hairless torsos in the gym!

即便你现在对追猎觅食没兴趣,但长跑依然有益身体。

Compared to other large mammals on Earth, we humans have relatively
little hair. This obvious fact is not so strange until we look at our
closest living relatives in the animal kingdom – chimpanzees and other
great apes. Why, might we ask, have we evolved to be almost hairless
when all other primates are still covered in fur? In
fact, bizarre as it may seem, our lack of hair has been the key to
our evolutionary success as a species.

Here’s where our special adaptations come in. The tendons and muscles in
our legs are very springy. They act like a pogo stick, converting
kinetic energy from the aerial phase into elastic potential energy,
which we can use later.

The most likely hypothesis to explain the loss of hair is that it
became necessary when early hominids 皇家88平台,moved to a more
open savannah habitat around 2 to 3 million years ago, when they
started to hunt big game.Hunting in open savannah meant being exposed to
the strong heat of the sun for several hours in the day and being in
danger of overheating. Being covered in hair prevented our ancestors
from losing heat fast enough. So, as Peter Wheeler, of Liverpool John
Moores University in the UK, explained, losing hair allowed them to
develop the ability to sweat and therefore to cool down. Early humans
could, as a consequence, be out at midday hunting and foraging. “It
would be [an] enormous advantage to be able to spend the entire midday
foraging,finding mates or fighting enemies”, Tamás Dávid-Barrett of
Oxford University says. “Sweating allows that, and for sweat to be
efficient you need to be mostly hairless”. The meat from hunting animals
gave early humans the energy to fuel their growing brain.

皇家88平台 2

为什么我们最早的祖先失去他们的毛发,而毛发有助于他们在寒冷的夜晚保暖这个问题,使得著名的进化学者查尔斯达尔文陷入深思,“没有人认为皮肤的裸露对人有直接的好处。”他认为人类失去毛发的主要原因是性选择。换句话说,我们宁愿要我们伴侣,而不想失去毛发。但是在这种偏好设置之前是什么导致我们的祖先开始失去他们的毛发?

那么,人类为何能成为如此卓越的长跑健将呢?

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