Hybrid Animals
美音、自然拼读、分级阅读与词汇复习
Table of Contents What Is a Hybrid Animal?
目录 什么是混合动物?
4 Human-Made Hybrids.
4"人马混血".
6 Natural Hybrids and the Tricky Definition of Species.
6 自然混合体和物种的诡秘定义。
9 When Species Overlap.
9 当物种重叠.
11 Whats the Big Deal?
第11条 有什么大交易吗?
13 Creatures by Design.
13由设计而来.
14 Animal Hybrids: Problem or Solution?
14 动物混合体:问题还是解决方案?
15 Glossary.
15 词汇。
16 What Is a Hybrid Animal?
16 什么是混合动物?
The ancient Greeks imagined creatures that were half one animal and half another—centaurs and minotaurs, griffons and manticores.
古希腊人想象的生物是半个动物和半个动物——摄像头和弥诺陶斯、格里芬斯和manticores。
These creatures may not exist, but animal hybrids do.
这些生物可能不存在,但动物杂交种确实存在.
They combine the traits of different species—and they are more common than most people realize.
它们结合了不同物种的特点——它们比大多数人意识到的更常见.
A hybrid is an animal that has parents of two different species.
杂交种(学名:Conus service)为双子科相生属的动物.
For instance, horses and donkeys are different species, but they are similar enough in appearance and behavior that they can mate with one another.
例如,马和驴是不同的物种,但它们在外观和行为上都非常相似,可以相互交配.
If the mother is a horse, the baby is called a mule, and if the mother is a donkey, the baby is called a hinny.
若母为马,子为骡;若母为驴,子为nny.
If different species mate, they don’t always give birth to hybrid young.
如果不同物种交配,
Parent species that are too different may not have live offspring, or their young may be weak or unhealthy.
太相异的亲生物种可能没有活生生的后代,或者其幼年可能体弱或不健康.
When two species do produce healthy offspring, though, the young usually have a combination of the parent species’ characteristics.
然而,当两个物种确实产生健康的后代时,年轻人通常具有母物种的特征。
The more closely related the parent species are, the more likely they are to have healthy hybrid offspring.
母种关系越密切,就越有可能有健康的杂交后代.
Most of the time, hybrid animals can’t reproduce.
多数时候,杂交动物无法繁殖。
That’s because reproductive cells— eggs and sperm—are trickier to make than regular body cells.
因为生殖细胞——卵子和精子——比普通体细胞更狡猾。
Take the mule: every cell in its body gets half its DNA from Mom (a horse) and half from Dad (a donkey).
取出骡子:身体中每个细胞从妈妈(一匹马)得到一半的DNA,从爸爸(一头驴)得到一半的DNA.
DNA molecules carry instructions for how cells operate—instructions for everything from hair color to ear shape.
DNA分子载有细胞如何运行的指令——从发色到耳朵形状的一切指令.
They encode the information that makes a horse a horse and makes a donkey a donkey.
他们编码了让一匹马成为一匹马,让一头驴成为一头驴的信息.
Hybrid animals often have different names depending on which species acted as which parent.
混合体动物往往有不同的名字,这取决于哪些物种是哪一个母体。
That’s because the characteristics of the hybrid animal are often determined by which species was the mother.
因为杂交动物的特性往往由哪个物种是母亲决定。
In the case of donkey- horse hybrids, mules are generally larger and hardier than hinnies.
在驴-马杂交种中,骡子一般比辛尼更大更硬.
Similar, but Not the Same Female Parent Male Parent Offspring Horse Donkey Mule Donkey Horse Hinny × × = = Mule Horse and donkey DNA carry much of the same information, which is why mules can survive.
类似但非同母异母异父异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母异母
Even though their cells don’t have a full set of horse DNA or donkey DNA, they still have all the information they need to function.
虽然他们的细胞没有全套的马DNA或驴DNA,
However, information is arranged differently on horse and donkey DNA.
然而,在马和驴DNA上的信息安排不同.
When the mule’s body tries to make reproductive cells, the mismatched DNA molecules throw a wrench in the gears.
当骡子的身体试图制造出生殖细胞时,不匹配的DNA分子会把扳手扔入齿轮.
Two species have to be closely related to produce hybrid offspring when they mate, but they have to be really closely related for their offspring to make healthy reproductive cells.
两个物种在交配时必须紧密地相接而生出杂交后代,但是它们必须真正地紧密地相接而生出后代,以生出健康的生殖细胞.
Human-Made Hybrids People have bred hybrid animals, such as mules, since ancient times.
人马混合体 人们自古就培育出骡子等杂交动物.
Mules are hardier and more sure-footed than horses.
木乃伊比马更坚硬 更有把握
They are also less sensitive to heat and less prone to injury.
它们也对发热不太敏感,也不太容易受伤害。
Zebra hybrids, sometimes called zebroids, are a more recent hybrid.
斑马杂交种,有时被称作"斑马杂交种",是一种更近代的杂交种.
Wild zebras are extremely difficult to train but are resistant to many diseases that affect horses and donkeys.
野生斑马训练极为困难,但能耐受影响马和驴的许多疾病.
Zebroids inherit a gentler personality from their domesticated parent and resistance to disease from their wild parent.
斑马从被驯化的父母那里继承了更温和的个性,从野生父母那里继承了抗病能力.
Another recent hybrid, the beefalo, combines the traits of bison (buffalo) and domesticated cattle.
另一个近代杂交种即牛肉花,结合了野牛(水牛)和驯化牛的特质.
Bison are much hardier than cattle and produce meat lower in fat than standard beef.
拜森比牛硬得多,并生产出比标准牛肉更低脂肪的肉.
However, like many wild animals, bison are difficult—even dangerous—to handle.
然而,与许多野生动物一样,野牛很难处理,甚至危险。
Beefalo hybrids are as easy to handle as ordinary cattle but have bison’s hardiness and independence.
比法罗杂交种和普通牛一样容易处理,但有野牛的硬性和独立性.
Like bison, beefalo are able to withstand both hot and cold temperature extremes.
和野牛一样,牛肉卡罗能够承受高温和高温的极端.
They produce meat that is low in fat and the bad type of cholesterol, with more protein than beef.
它们能出产脂肪含量低和胆固醇不良的肉类,蛋白质比牛肉多.
A liger is a hybrid of a male lion and a female tiger.
立格是雄狮和雌虎的杂交种.
Ligers grow about twice as large as either parent species; the largest known healthy male weighs nearly 1,200 pounds (544 kg)!
乳头长出大约两倍于母种;最大已知健康雄性体重近1200磅(544公斤)!
They are usually tawny colored, like lions, with pale bellies and faint stripes, like tigers.
它们通常有t色,有狮子等颜色,有苍白的腹部和微弱的条纹,有老虎等.
A zebra-donkey hybrid shows traits of both.
斑马-驴杂交表现出两者的特质.
Ligers never occur naturally since lions and tigers live in different habitats.
由于狮子和老虎生活在不同的栖息地中,所以立革者从不会自然地出现.
Accredited zoos avoid interbreeding the big cats, but independent breeders sometimes raise big cat hybrids as curiosities.
经认证的动物园避免了与大猫的繁殖相生,但独立的饲养者有时会将大猫杂交饲养为奇特.
Other big cat hybrids include leopons (leopard × lion), jaguleps (jaguar × leopard), and lijaguleps (lion × jagulep).
其他大猫杂交种有:花豹(leopard × 狮子),花豹(jaguar × 豹)和花豹(lijaguleps (lion × jagulep).
Until recently, people could only obtain hybrids between species similar enough to mate with each other.
直到最近,人们只能得到相似的物种之间的杂交体,以便相交.
Some species, while somewhat similar, can’t—or won’t—mate, so their hybrids didn’t exist.
有些物种虽然有些相似,但不能或不会成为伴侣,因此其杂交种并不存在。
For instance, even if given the opportunity, camels and llamas would rarely mate.
例如,即使有机会,骆驼和骆驼也很少交配。
When modern medicine provided a way to fertilize eggs in a test tube, a camel-llama hybrid became possible.
当现代医学提供了一种在试管中受精卵的方法后,骆驼-骆驼杂交成为可能.
Scientists hope this hybrid, called a cama, will couple the camel’s strength and hardiness with the llama’s sweeter disposition.
科学家们希望这种被称为"骆驼"的杂交种,能将骆驼的强度和硬度与骆驼更甜美的处理相配合.
Hercules, the world’s biggest cat, poses with little brother Aries.
赫拉克勒斯是世界上最大的一隻猫,
Both are ligers.
两者都是绳子.
Natural Hybrids and the Tricky Definition of Species Hybrid animals can arise whenever related species interbreed—which can occur whenever they live in the same environment.
自然杂交种和物种杂交种的诡秘定义在相关物种相互繁殖时都可能出现——在相同环境中生活时都会发生。
Identifying hybrids can be surprisingly difficult, though, because it’s surprisingly difficult to define when animals are separate species.
然而,发现杂交种会很困难, 因为动物是独立的物种,
Scientists often define a species as a group of individuals with two important characteristics.
科学家经常将一个物种定义为具有两个重要特征的个体群.
They have the potential to interbreed in nature.
它们有可能在自然界中相互影响。
to reproduce.
以繁殖。
Same or Different Species?
相同还是不同的物种?
It can be difficult to tell whether two animals are the same species based on appearance alone.
单凭外观,可能很难分辨出两个动物是否是同一种物种.
These two dog breeds look quite different from one another, but they are considered the same species— Canis lupus familiaris.
这两只狗的品种看起来相去甚远,但它们被认为是同一种物种——Canis lupus familiers.
Two fruit flies may look like twins but actually be different species.
两只果蝇可能看起来像双胞胎 但其实是不同的物种
Great Dane Chihuahua Ring species provide a great example of how it can be difficult to determine the line between hybrids and distinct species.
伟大的丹·奇瓦瓦 环形物种提供了一个很好的例子,说明如何难以确定杂交种与不同物种之间的分界线.
To understand ring species, imagine a group of preschoolers sitting in a circle.
为了了解环形物种,想象一群学龄前儿童坐在一圈.
Each child represents a separate species sitting within arm’s reach of two others.
每个孩子代表着另外两个物种,
When Species Overlap Evidence suggests that ring species members change slowly as they adapt to specific environmental conditions.
当物种重叠时 有证据表明,环形物种成员随着适应特定环境条件而变化缓慢.
The ranges of individual species overlap in some regions; where they do, hybrids arise.
在一些地区,单个物种的范围相重叠;如果有,则会出现杂交种.
With far more of each parent species than the hybrids, though, the parent populations are not greatly affected.
然而,每个母种比杂交种多得多,但母种没有受到很大影响。
Ring species Ensatina eschscholtzii Now imagine them playing a game of telephone: the first child whispers to the second, who whispers to the next, and so on.
环形物种Ensatina eschscholtzii 现在想象一下他们玩电话游戏:第一个孩子对第二个孩子低语,另一个孩子低语,等等.
When the last child gets the message, it’s usually completely different from the starting words!
当最后一个孩子收到消息时,
The changes in the whispered message are similar to the changes seen around a circle of ring species.
耳语中信息的变化与环形物种一圈所见的变化相类似.
Each species is similar to those on either side—similar enough that they can interbreed— until you get back to the starting point.
每个物种都与两侧的物种相似——类似,可以互相繁殖,直到你回到起点。
The starting and ending species are the most different from one another and cannot interbreed.
始末种相去相去相去最相去相去相去相去相去而相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相去相相去相去相去相去相去相去相去相去相去相相去相去相去相相相相相去相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相相
Sometimes two species that were isolated from one another are brought together abruptly.
有时,两个相互隔离的物种突然聚集在一起。
In this situation, hybrids can cause problems for their parent species by competing for food, territory, or other resources.
在这种情况下,杂交种通过争夺食物,领地或其他资源,可能会给其母种带来问题.
They may compete for mates, potentially changing the genetic makeup of the original species.
它们可能争夺伴侣,可能改变原始物种的基因组成。
Over the past decades, changing environmental conditions due to climate change have brought together many previously separated species.
在过去几十年中,气候变化导致的环境条件不断变化,使许多先前分离的物种聚集在一起。
Climate change has had its greatest effects in the Arctic, where some native species are changing their natural ranges in response to rising temperatures and melting sea ice.
气候变化在北极影响最大,一些当地物种正在改变其自然范围,以应对气温上升和海冰融化。
Animals from farther south that might have previously found northern regions too cold are extending their ranges northward.
来自更南端的动物 曾经发现北方地区太冷 正在向北延伸
The result is that species that used to be geographically separate—such as grizzly and polar bears—now interbreed.
结果,过去在地理上是分开的物种——如灰熊和北极熊——现在在繁殖。
One of the first grizzly-polar bear hybrids, called a grolar bear, was spotted in 2006.
2006年发现最早的灰熊-极地熊杂交种之一,被称作"地鼠熊".
The bear had thick white fur, brown legs and paws, and a wide, grizzly-like head.
熊有厚白的皮毛,棕色的腿和爪子,并有宽阔,灰熊般的头.
Other grolar bears have been identified since that time, which suggests that grizzlies and polar bears are regularly interbreeding in the wild.
从那时起,其他地沟熊也被识别出,这表明灰熊和北极熊经常在野外繁殖.
What’s the Big Deal?
什么是大交易?
So grizzlies and polar bears might have some brown-and-white grolar bear cubs.
所以灰熊和北极熊可能有一些棕白色的花生熊.
Is that really a big deal?
这真的很重要吗?
If plenty of polar bears roamed the world, the answer might be no.
如果世界上有很多北极熊,答案可能是否定的。
The problem is that polar bears are at risk of going extinct—so every polar bear birth makes a difference.
问题是北极熊有被灭绝的危险,
It becomes a numbers game: the more polar bears interbreed with grizzly bears, the more their genes—specialized for surviving in the harsh Arctic environment—get diluted by grizzly bear genes.
它成为了一款数字游戏:越是北极熊与灰熊相生,它们的基因越多——专门在恶劣的北极环境中生存的基因——被灰熊基因稀释.
Eventually, polar bears might simply disappear.
最终北极熊可能会消失
On top of that, grolar bears may not be very well adapted to either of their parents’ environments.
此外,地鼠熊可能不太能适应父母双方的环境。
Grolar bears in a German zoo seem to have a polar bear’s instinct for seal hunting but not its strong swimming ability.
德国动物园的格罗拉尔熊似乎有北极熊捕海豹的本能,但没有强大的游泳能力.
At this point, no one knows whether these hybrids survive as well as non-hybrids in the wild.
此时,没有人知道这些杂交种是否在野外生存以及非杂交种是否生存.
While not a confirmed grolar bear, this bear’s body shape, short neck, and odd face (when compared to other polar bears) suggest that it is a grizzly-polar hybrid.
虽然这只熊不是被证实的地鼠熊,但是它的身体形状、短颈和奇异的相貌(当与其他北极熊相比时)表明它是一种灰熊-极地杂交体。
Creatures by Design What if you want a hybrid animal that combines traits from species so different that even mating in a test tube won’t work?
由设计而来 如果你想要一种混合的动物 结合物种的特异性 以至于连在试管里交配都行不通呢?
How about these traits: the ability to produce spider silk (an ability unique to spiders) and the ability to produce lots of milk (an ability limited to mammals)?
这些特质如何:生产蜘蛛丝的能力(蜘蛛独有的能力)和生产出大量牛奶的能力(仅限于哺乳动物的能力)?
Spider silk is stronger and more flexible than steel or Kevlar, as well as resistant to bacterial growth.
蜘蛛丝比起钢或克夫拉尔更强活和灵活,也耐受细菌生长.
These traits make it ideal for many medical uses.
这些特征使得它成为许多医学用途的理想.
Researchers hope to use it to create artificial ligaments or nearly invisible stitches for eye surgery patients.
研究人员希望用它来为眼科手术患者创造人工韧带或近乎无形的缝合.
Unfortunately, it takes fourteen thousand spiders to make one ounce of silk.
不幸的是,用一万四千只蜘蛛来做一盎司丝绸
Since spiders tend to eat their neighbors, large-scale “spider farms” are out of the question.
由于蜘蛛往往吃邻居,大规模“蜘蛛农场”是不可能的。
Instead, scientists used genetic engineering techniques (directly manipulating an animal’s genes) to insert spider silk proteins into goat DNA.
相反,科学家利用遗传工程技术(直接操纵动物基因)将蜘蛛丝蛋白插入山羊DNA.
The goats then produce spider silk proteins in their milk, which is easy to collect.
山羊再在其乳中出产蜘蛛丝蛋白,易于采集.
Someday, researchers hope to engineer goats that can produce commercially useful amounts of spider silk.
研究者们希望有一天能制造出能够生产出商业上有用的数量蜘蛛丝的山羊.
Since spider genes were inserted into goat cells in a laboratory, “spider goats” are considered transgenic rather than hybrid animals.
由于蜘蛛基因被插入实验室的山羊细胞中,"蜘蛛山羊"被认为是转基因动物而不是杂交动物.
Animal Hybrids: Problem or Solution?
动物混合体:问题还是解决方案?.
In the past, scientists thought that animal hybrids represented an evolutionary dead end.
过去,科学家认为动物杂交体代表了进化的死角.
Most hybrids were sterile, and even those that could reproduce usually carried a combination of their parents’ traits.
大多数杂交种是无菌的,即使是能繁殖的杂交种,通常也带有父母的特质。
The parents were probably well adapted to their specific environments; by combining their characteristics, the hybrid would end up adapted to neither.
父母可能很好地适应了他们的具体环境;通过结合他们的特征,混合体最终将适应于两者。
In most cases, this is exactly what we see in nature: hybrid species are usually poorly adapted to their environments and often fail to survive and reproduce.
在大多数情况下,这正是我们在自然界所看到的:杂交种通常不适应其环境,往往无法生存和繁殖.
However, when a species faces drastic environmental changes, it may not be able to adapt to the new conditions quickly enough to survive.
然而,当一个物种面临急剧的环境变化时,它可能无法迅速适应生存所需的新条件。
Hybrids provide a way for two species to exchange genetic information.
混合体为两个物种提供了交流遗传信息的途径.
A hybrid animal could potentially gain traits that would allow it to survive where one or both parents could not.
杂交动物有可能获得特性,使其在父母一方或双方无法生存的地方能活下来。
Are hybrid animals a threat to the survival of at-risk species like polar bears?
杂交动物是否对北极熊等濒危物种的生存构成威胁?.
Or are they nature’s way of helping species cope with rapidly changing environmental conditions?
还是大自然帮助物种应付迅速变化的环境条件的方法?
They may be a bit of both—only time will tell!
可能只有时间知道,