Life Spans
美音、自然拼读、分级阅读与词汇复习
Table of Contents An Ancient Clam.
An-Clam目录。
4 What Is a Life Span?
4 生活号是什么?
5 Cells and Aging.
5 细胞和衰老。
6 Body Size.
6个体型
8 Adaptations.
8 适应.
12 Environments.
12 环境。
13 Extraordinary Abilities.
13 特异功能.
14 Still Learning.
14 还在学习。
15 Glossary.
15 词汇。
16 An Ancient Clam In 2006, scientists working on a research project off the coast of Ireland scooped up a quahog (KOH-hog)—a type of clam—from the ocean floor.
16个古老的Clam 2006年,在爱尔兰沿海从事研究项目的科学家从洋底挖出一头ho(KOH-hog)——一种蛤.
The researchers froze the clam and later examined it under a microscope.
研究人员冻结了蛤,后来在显微镜下检查.
Quahogs lay down rings every year as they grow, just as many trees do.
Quahogs每年在生长时会像许多树木一样倒下环.
When the scientists counted the rings, they realized that this particular clam was 507 years old!
当科学家们数出戒指时,他们意识到这只特殊的蛤是507年了!
Who knows how much longer the clam would have lived if it had not been caught?
谁知道蛤没有被逮住会活多久?
Long-lived ocean quahogs live on the floor of the North Atlantic Ocean.
长生海洋 qua栖息于北大西洋地上.
Can you guess how old this quahog is?
你能猜到这个怪人多大了吗?
What Is a Life Span?
什么是"生命"吗?
Different types of living things live for very different amounts of time.
不同种类活物的活活时间非常不同.
The maximum amount of time a species can live is called its life span.
一个物种所能活到的最长时间被称为它的寿命.
A worm might have a life span of only two weeks, while a tortoise might live for one hundred years.
蠕虫的寿命可能只有两周,而龟可能活了一百年.
A few types of organisms even seem to defy time altogether.
几类生物甚至似乎完全无视时间。
Most living things slowly become less and less healthy once they reach adulthood.
大部分活物一旦成年后会慢慢变得越来越不健康.
This is a natural result of the process of aging.
这是衰老过程的自然结果.
What exactly is aging, and why do some animals live so much longer than others?
什么是老化, 为什么有些动物活得比其他动物长?
A giant tortoise goes for a stroll on Isabela Island in the Galapagos Islands.
一只巨龟在加拉帕戈斯群岛的伊莎贝拉岛散步
Giant tortoises are among the longest-lived animals with backbones.
巨龟属(学名:Cyclea)是具有脊椎动物中寿命最长的动物.
Cells and Aging Aging has several causes, some of which involve cells, the tiny building blocks of life.
细胞和衰老有几种原因,有的涉及到细胞,生命的微小基石.
Over time, the cells in a life-form replace themselves through a process known as cell division.
随着时间的推移,生命形态中的细胞通过被称为细胞分裂的过程来取而代之.
Cell division allows a cell to make a copy of itself and then die off, to be replaced by the new cell.
细胞分会允许一个细胞自行做一个拷贝后死亡,取而代之的是新细胞.
As living things get older, though, this replacement process slows down.
然而,随着活物的老化,这个替换过程会放慢.
Mistakes during the copying process can result in copied cells that are damaged.
复制过程中的错误可能导致被复制的单元格被损坏.
Even if the copies are perfect, the new cells just don’t work as well as the old ones did.
即使复制品很完美,
Also, the oxygen in the air we breathe can slowly damage our cells over time in a similar way to how water and oxygen can cause iron to rust.
另外,我们呼吸的空气中的氧气会随着时间的推移慢慢地破坏我们的细胞,其方式类似于水和氧气会如何使铁生锈.
Eventually, our old, damaged cells can’t keep our bodies working well enough to stay healthy.
我们的老旧、受损的细胞无法保持身体健康。
At that point, we get sick and die.
这时候,我们生病而死。
How Long Do Different Animals Live?
异兽活多长?
Some types of worms and flies have bodies mostly made up of cells that can’t divide.
有些种类的蠕虫和苍蝇的体内大多由无法分化的细胞所组成.
Their bodies wear out even more quickly than those of other types of animals.
他们的身体磨损比其他种类的动物更快.
Understanding how cells work explains why all living things die, but why do some of them age and die much sooner than others?
理解细胞是如何工作的 解释为什么所有活物都会死, 但为什么有些活物会比其他活物老而死快得多?
The answer involves several factors working together.
答案涉及若干因素。
This cell is almost done with the process of copying itself through cell division.
这个单元格几乎完成了通过单元格分割复制自身的过程.
Jeanne Calment at age 120 Jeanne Calment at age 20 Body Size People noticed long ago that larger animals tend to live longer than smaller ones.
贞德·卡尔特120岁 贞德·卡尔特20岁 身体大小的人很早就注意到 体型比体型小的动物要活得更长
Elephants and whales, for example, have much longer life spans than mice and rats.
例如,大象和鲸鱼的寿命比小鼠和大鼠长得多。
Size is an important factor in how much an animal is at risk of being eaten by other animals.
体积是动物面临被其他动物吃掉风险的重要因素.
Large animals such as horses and giraffes are able to fend off predators much better than smaller ones.
马和长颈鹿等大型动物比起更能抵御捕食者。
Because they are less at risk from predators, large animals have evolved to mature and reproduce at a slow pace.
由于受捕食者的威胁较小,大型动物已经慢慢地演化为成熟和繁殖.
They often have just one or two babies at a time.
他们经常一次只生一两个孩子.
They might go several years between babies.
他们可能会在婴儿之间度过几年
That slow pace is fine, though, because they usually live long enough to keep their populations steady.
不过,这种缓慢的步伐是好的,因为他们通常活得足够长,可以维持其人口的稳定。
Large size can help some animals fend off predators.
大可以帮助一些动物抵御掠食者.
One well-aimed kick from a giraffe can kill a lion.
长颈鹿踢一脚就能杀死一头狮子
Smaller animals don’t have the same luxury.
更小的动物没有同样的奢侈品。
They are generally at much higher risk from predators.
它们通常受到捕食者的威胁更大。
They need to grow up and breed as soon as possible since death can come at any time.
他们需要尽快成长和繁殖 因为死亡随时可能降临
Animals in this group, such as mice and rabbits, need to have many babies very quickly to keep their populations steady.
这个群体中的动物,如小鼠和兔子,需要非常快地生出许多婴儿来保持种群的稳定.
Rabbits can breed as often as twelve times per year, producing up to fourteen rabbits per litter.
兔子每年能繁殖多达12次,每条垃圾可出产多达14只兔子.
That’s a bunch of bunnies!
这是一群兔子!
Labord’s chameleons also have short life spans.
Labourd的变色龙也有短暂的寿命.
They hatch in November, during Madagascar’s rainy season, and only live four to five months.
在马达加斯加雨季期间,
They grow up quickly, reaching adulthood in just two months.
他们长得很快,仅仅两个月就成年了。
Adults breed as soon as they can and then begin to die off.
成人尽快繁殖 然后开始死亡
Before they die, they make sure to lay their eggs underground ahead of the dry season to help their species stay alive.
在它们死前,它们要确保在干季前将卵放入地下来帮助它们的物种活下来.
A Labord’s chameleon clings to a branch in Kirindy Mitea National Park, Madagascar.
一个拉博德的变色龙紧贴着马达加斯加Kirindy Mitea国家公园的分园。
Cramming a lot of life into a short amount of time is most common among insects.
在昆虫中将很多活体挤入到很短的时间中最为常见.
Mayflies begin life underwater as nymphs.
Mayflies在水下开始生命 以尼姆斯。
Once they grow up and leave the water to take wing, their time is nearly up.
一旦他们长大并离开水去取翼,他们的时间就快到了.
Most adult mayflies live for fewer than twenty-four hours, and the females of one species live for only five minutes!
多数成年蝴蝶活活不到24小时,一个物种的雌性活活不到5分钟!
In that time, they must find a partner, mate, and lay eggs in water.
在那个时候,他们必须找到伴侣,交配,并在水中产卵.
Cecropia moths follow much the same cycle.
克克罗匹亚蛾的周期也大致相同.
After a season as a caterpillar, the adult moths emerge.
作为毛毛虫的一季后,成年蛾出现.
These spectacular silk moths live for just five days.
这些壮观的丝蛾只活了五天
Their only job is to find a partner, mate, and lay up to one hundred eggs.
他们唯一的工作就是找到一个伙伴,交配, 并下到一百个鸡蛋。
They don’t even have mouthparts to eat with!
他们连口吃都没有!
Cecropia caterpillars can grow up to 11.
克克罗匹亚毛虫可长到11个.
4 centimeters (4.
4厘米( C) (4个)
5 in.)
5 in. (中文(简体) ).
long.
长.
Adult moths can have a wingspan up to 15.
成年飞蛾的翅膀可长达15个.
2 centimeters (6 in.)
2厘米(6英寸).
Smaller animals don’t always live shorter lives than larger ones.
更小的动物并非总能活得更短,
Cockatoos are fairly small birds, but they can live for more than one hundred years.
科克托斯是相当小的鸟类,但它们可以活到一百多岁.
And even tiny, high-energy creatures such as Brandt’s bats can live longer than forty years.
而即使是小而高能的生物,如勃兰特的蝙蝠,也能活到四十多岁.
Some tortoises are huge, but even some smaller ones can live for a century.
有些乌龟很大,但即使是一些较小的乌龟也能活上一个世纪.
Certain types of moles can live for six or seven years.
某些种类的地鼠可以活到6到7年.
That may not sound like a long time, but it’s about 50 percent longer than most animals their size.
但比大多数动物的体型还要长50%。
A Major Mitchell’s cockatoo (left) rests after eating grass seeds.
Mitchell少校吃草籽后,
A mole (right) sticks its head out of its underground burrow.
一只内鬼(右)从地底下的洞穴里伸出头来。
Adaptations One explanation for how small animals can live so long is that some have adapted to their living conditions by developing extra defenses.
适应 对于小动物如何能活得那么长的一个解释是,有些人通过开发额外的防御,适应了他们的生活条件.
Tortoises have strong shells, birds can fly, bats can flock together for protection, and moles are great at digging tunnels and hiding underground.
乌龟有坚固的贝壳,鸟可以飞起,蝙蝠可以群起一起保护,而地鼠也擅长挖掘地道并躲入地下.
Still, some animals of similar sizes and habitats age at very different rates.
尽管如此,一些体型和栖息地年龄相近的动物却以非常不同的速度生长.
These differences are usually because certain animals have ways to keep their cells healthy longer.
这些差异通常是因为某些动物有方法使其细胞保持更长时间的健康.
Cockatoos and other parrots have developed special processes in their bodies that minimize damage to their cells.
科克托斯等鹦鹉已经在其体内发展出将细胞损伤最小化的特殊过程.
Similarly, naked mole rats have a protein that can quickly identify and repair problems with cells.
同样地,裸鼠有蛋白质,可以快速识别并修复与细胞有关的问题.
This protein helps naked mole rats live as long as thirty-one years.
这种蛋白质能帮助裸鼠鼠活到三十一岁.
That’s decades longer than would be expected based on their size alone!
数十年来,
Naked mole rats have several adaptations that help them have impressive life spans for their size.
裸鼠鼠有几种适应,帮助其有令人印象深刻的寿命来适应体型.
Environments Adaptations allow animals to live in different environments, which can also affect their life spans.
适应让动物生活在不同的环境中,这也可能影响它们的寿命.
Many of the longest-lived animals survive in cold environments in the deep ocean.
许多寿命最长的动物在深海的寒冷环境中生存.
Bowhead whales often live for well over 100 years, but at least one individual has made it past 200.
鲍头鲸通常活了100多年,但至少有一人活了200年。
Greenland sharks slowly cruise the Arctic Ocean.
格陵兰鲨鱼缓慢地在北冰洋巡航.
One of these giant sharks reached 392 years of age.
其中一头巨鲨已达392岁.
These animals have adapted to extreme cold by having slower heart rates and metabolism—the chemical reactions within their bodies.
这些动物通过心率和新陈代谢——体内的化学反应,适应了极端寒冷。
Evidence suggests that slowing down these body processes also slows down aging.
有证据表明,减缓这些身体过程也会减缓老龄化。
Welwitschia Extraordinary Abilities A few creatures go beyond the ability to simply lead a long life.
Welwitschia 特殊设施 少数生物超越了仅仅过上长寿的能力.
They can do truly special things.
他们可以做真正特殊的事情。
The African lungfish lives in shallow pools and breathes air at the surface.
非洲肺鱼生活在浅水池中并呼吸出表面的空气.
During a drought, it can postpone death by burrowing into moist mud.
在干旱期间,它可以通过将死亡挖入湿泥来推迟.
It turns around and places both its head and tail just inside the tunnel’s entrance.
它转过身来,把头和尾部都放在隧道入口处。
Then it builds a mucus cocoon around itself, leaving a small hole to breathe through.
然后它自己周围会建起一个黏液茧,留下一个小洞来呼吸.
In this cocoon, the lungfish can survive for months and even years without drinking or eating.
在这个茧中,肺鱼可以生存数月甚至数年而不饮用.
When the rains return, it breaks out of its sticky safety net to continue its life in a muddy pool of water.
当降雨回来时,它从粘稠的安全网中被冲出来,以活在泥水池中.
The immortal jellyfish is even more bizarre.
长生不老的水母更奇怪
If it faces a threat to its well-being, it can change from a mature adult jellyfish back into a group of polyps.
如果它面临对自身福祉的威胁,它可以从成熟的成年水母回转而形成一组多肽类.
The polyps pop off and eventually become individual adult jellyfish.
多肽会发作,最终成为单个的成年水母.
While no single jellyfish of its kind lives forever, this species has found its own kind of immortality.
虽然没有一种同类水母能永远活下来,但这种物种已经发现了自己的长生不老.
Still Learning Scientists still have much to learn about aging and life spans.
仍然学习科学家仍然有很多关于衰老和生命期的知识.
The animal kingdom holds many fascinating examples of different life spans that show how cells, body size, metabolism, adaptations, and the environment each play a role in an animal’s life span.
动物王国拥有许多不同生命期的迷人例子,表明细胞、体积、新陈代谢、适应和环境在动物生命期中如何发挥作用。
Studying animal life spans can help us understand the many factors that contribute to aging and may one day allow us to live longer, healthier lives.
研究动物的寿命可以帮助我们了解导致衰老的诸多因素,并可能有一天使我们能够活得更长,更健康.
A bowhead whale breaches in the arctic waters off Bering Land Bridge National Preserve, Alaska.
在阿拉斯加白令地桥国家保护区外的北极水域 有一条弓头鲸断裂.