Skin Color
美音、自然拼读、分级阅读与词汇复习
Table of Contents A World of Diversity.
多样性世界目录。
4 Melanin and Skin Color.
4 梅兰宁与相克相克.
5 Melanin and Sun Protection.
5 梅兰宁与太阳保护.
7 Where in the World?
页:1 哪里是这个世界?
10 Skin Pigmentation Conditions.
10 皮肤外观条件。
13 Solving UV Mismatches.
13 解决UV Mismatches。
15 Glossary.
15 词汇。
16 A World of Diversity If you visit Singapore, Toronto, or New York City, you’ll see people from all around the world.
16 多样性世界 如果你访问新加坡、多伦多或纽约市,
These cities are among the most diverse places on Earth.
这些城市是地球上最多样化的地方之一.
People speak different languages and have different traditions.
人们会说不同的语言,有不同的传统.
They look different, too.
他们看起来也不同
Their skin color ranges from almost black to pale pink and every shade in between.
它们的皮肤颜色从几乎黑色到苍白的粉红色, 以及中间的每一个阴影.
Scientists have studied the reasons for different skin colors.
科学家研究了不同肤色的原因.
Their discoveries make sense, and they might also amaze you.
他们的发现是有道理的,他们可能也会令你惊叹.
People crossing the street in Toronto, Canada, show how diverse some cities can be.
在加拿大多伦多,人们穿过街道,显示出一些城市可以有多多样化.
Melanin and Skin Color Skin color is mostly determined by melanin, a pigment in animals and plants.
梅兰宁与斯克色相色多由梅兰宁所决定,是动植物中的一种色素.
Melanin is mainly located in the outer skin layer, called the epidermis.
梅兰宁主要分布于外皮地层中,被称作"地层".
It’s also found in hair and eyes.
在头发和眼睛中也发现了它。
This pigment is produced by special cells called melanocytes.
这种色素由特有细胞所出产,称为"黑色素".
Melanin is controlled by at least six genes.
梅兰宁被至少六个基因所控制.
Genes are parts of cells that control many aspects of appearance and behavior.
基因是细胞中控制外观和行为诸多方面的部分.
They are basic units of heredity passed down from parents to offspring.
它们是从父母传给后代的基本遗传单元。
That’s why children tend to have similar skin color to their parents.
所以孩子的肤色与父母相似。
Human Skin There are two types of melanin.
人类皮肤 美兰素有两种.
Eumelanin is dark brown to black in color.
欧梅兰宁颜色为深棕色至黑色.
Pheomelanin is red to yellow.
滇米兰素为红色至黄色.
People produce different amounts of the two types.
人们会产生两种类型的不同数量.
More of the first type makes skin darker, while more of the second makes skin lighter.
更多的第一种类型使皮肤更暗,而更多的第二种类型使皮肤更轻.
Skin color is also affected by how many melanin particles a person has and how big those particles are.
皮肤颜色还受到一个人有多少个黑色素粒子以及这些粒子有多大的影响.
In fact, those factors have a greater influence on skin color than the balance of eumelanin and pheomelanin.
事实上,这些因素对皮肤颜色的影响大于欧梅兰宁和麻黄素的平衡。
The color of lighter skin is also partly determined by what’s under it.
皮肤颜色较轻,
Blood makes skin pinker.
血使皮肤更粉.
Body fat and carotene, a red-orange pigment, also influence the color of skin.
体脂肪和红橙色素也影响皮肤的颜色.
Melanin causes brown spots on the peels of ripe bananas.
梅兰宁在成熟的香蕉皮上会出出出棕色斑点.
Zebras have dark skin because of melanin.
斑马有深色皮肤,因为有黑色素.
Cells that produce melanin transfer it into just some of the hairs in a zebra’s coat.
产生黑色素的细胞 将它转移到斑马外衣的一些发型中
Melanin and Sun Protection Light from the Sun shines on Earth, and some of that light is invisible ultraviolet radiation.
梅兰宁和太阳保护光从太阳照耀出地球,而其中的一些光是看不见的紫外线辐射.
Ultraviolet (UV) radiation can damage cells and result in skin cancer and other health concerns.
紫外线(UV)辐射会破坏细胞并导致皮肤癌和其他健康问题.
Melanin—especially eumelanin, the darker kind—protects people from the harmful effects of UV radiation by preventing it from passing through the epidermis.
Melanin——特别是eumelanin, 更黑暗的种类——通过防止紫外线辐射穿过地表线来保护人们免受紫外线辐射的有害影响。
In fact, dark skin is a sort of built-in sunscreen, protecting against UV skin damage at least twice as well as pale skin.
事实上,深色皮肤是一种内置的防晒剂,可以防止紫外线皮肤被损伤,至少是苍白皮肤的两倍.
Melanin also protects the body’s stores of folate, a B vitamin that helps to fuel cell production.
Melanin也保护体内的叶酸盐储存,
Ultraviolet (UV) radiation produces three main types of rays.
紫外线辐射产生出三种主要的射线.
They decrease in length from A to C but increase in intensity.
它们从A到C长度下降,但强度增加。
The shorter the wavelength, the more potential for damage.
波长越短,破坏的可能性就越大.
Fortunately, UV-A accounts for 95 percent of the UV radiation that reaches Earth’s surface.
幸运的是,紫外线A占了到达地表的紫外线辐射的95%。
Yet even UV-A rays are thought to play a role in some skin cancers.
然而即使是紫外线也被认为在某些皮肤癌中起一定作用.
Ultraviolet (UV) Radiation UV-A ages skin cells, causes wrinkles UV-B causes tans, sunburn, and most skin cancers UV-C does not reach Earth Source: University of Pittsburgh Medical Center However, UV radiation also has a beneficial side.
紫外线(UV) 辐射紫外线-A年龄的皮肤细胞,引起皱纹紫外线-B引起晒黑,晒伤,而大多数皮肤癌紫外线-C没有到达地球 资料来源:匹兹堡大学医学中心 然而紫外线辐射也有有利的一面.
Exposing bare skin to sunlight causes the body to produce vitamin D.
裸出皮肤到阳光下会使身体产生维生素D.
This vitamin is important for strong bones, a healthy immune system, and many other body functions.
这种维生素对于强骨,健康的免疫系统,以及许多其他身体功能都很重要.
Darker skin blocks UV radiation enough to reduce the amount of vitamin D being produced.
更深的皮肤会阻断紫外线辐射,以降低所生成的维生素D的数量.
As a result, people with darker skin need to spend more time in the sun to make enough vitamin D.
因此,皮肤更暗的人需要花更多的时间在太阳下,来制作足够的维生素D.
Lighter skin produces vitamin D more easily.
更轻的皮肤更容易产生维生素D.
The Eyes Have It Eye color is determined by the amount of melanin in the iris—the colored ring around the center.
眼睛的颜色是由虹膜中的黑色素量决定的——中央周围的彩色环.
Eye color ranges from very pale blue to dark brown.
眼色从非常苍白的蓝色到深棕色不等.
Darker eyes contain more melanin than lighter eyes.
更暗的眼中含有比更轻的眼多的黑色素.
Melanin helps protect eyes from sunlight, just as it helps protect skin.
梅兰宁有助于保护眼睛免受阳光照射,就像它有助于保护皮肤一样.
Different people have different colors of skin based on their genes, but another factor also affects skin color.
不同的人根据他们的基因有着不同的皮肤颜色,但另一个因素也影响了皮肤颜色.
If you’ve ever had a suntan, you know about this second factor.
如果你有晒过太阳,你知道第二个因素。
Exposure to UV radiation can cause melanocytes to increase their production of melanin and turn skin a darker color.
受紫外线辐射会使黑色素增产,使皮肤变暗.
Whether a person tans or burns depends on his or her skin type.
一个人晒黑或烧伤取决于他或她的皮肤类型.
In some people with pale skin, some of their melanocytes make more melanin than others in response to sun exposure.
在有的皮肤苍白的人中,有的黑色素比有的更能活出黑色素,以应对被阳光照射.
These people get freckles instead of an overall suntan.
这些人得到雀斑 而不是整个太阳。
Now you know that melanin controls skin color and helps protect skin from UV rays.
现在你知道黑色素控制了皮肤颜色 有助于保护皮肤免受紫外线照射
But why do different people have different amounts and types of melanin—and therefore different skin colors?
但为何不同的人有不同量和种类的美兰素,
To answer that question, we need to go far back in time to the first humans.
为了回答这个问题,我们需要追溯到最早的人类。
People with red hair often have freckles.
有红发的人经常有雀斑.
Where in the World?
哪里是这个世界?
Scientists generally agree that the first humans came from Africa.
科学家普遍认为,最早的人类来自非洲.
Because of its location with regard to the equator, sunlight strikes much of Africa more directly than many other parts of the world.
由于太阳位于赤道地区,因此它比世界上许多其他地区更直接地袭击非洲。
About two million years ago, Earth underwent a long dry spell that forced early humans to find ways to survive in dry, open lands.
大约两百万年前,地球遭受了长期的干燥咒语,迫使早期人类在干燥而开阔的地盘上寻找生存的方法.
They had to stay cool while moving around in the heat of the day.
他们必须保持冷静,同时在白天的发热中移动。
Scientists think this is when early humans lost most of their body hair and developed the ability to sweat.
科学家认为这是早期人类失去大部分身体发型并发展出出出汗能力的时候.
Earth and UV-B Radiation low UV exposure high UV exposure A map created from measurements taken by NASA’s TOMS 7 satellite shows the distribution of UV-B radiation on Earth’s surface in November 2003.
根据美国航天局TOMS 7号卫星的测量结果绘制的地图显示2003年11月紫外线-B辐射在地表的分布情况。
UV-B burns unprotected skin in as little as fifteen minutes.
紫外线B在15分钟内会烧出无防护的皮肤.
Skin pigmentation is thought to have developed around the same time.
皮肤色素被认为是大约同时得到发展.
It would have protected early humans’ mostly hairless skin from UV radiation and protected their stores of the vitamin folate.
保护人类早期的无毛皮肤免受紫外线辐射,
Sometime between fifty and eighty thousand years ago, some early humans migrated to colder parts of the world.
5万到8万年前的某个时候,一些早期人类迁徙到更寒冷的地区.
Moving away from the equator, they were exposed to less intense sunlight and therefore less UV radiation.
远离赤道后,它们受到的阳光强度较低,因此紫外线辐射也较少。
Because of the reduced UV radiation, they had less need for heavily pigmented skin.
由于紫外线辐射减少,因此它们不需要大量染色皮肤。
There was also less danger of losing folate stores.
失去叶酸盐店的风险也较小。
How Sunlight Strikes Earth North Pole South Pole Equator Nearer the poles, sunlight strikes Earth less directly.
日光如何打击地球 北极南极赤道 更靠近极地,阳光更不直接撞击地球。
As a result, the land receives less heat and light.
故地取取之热而取之少.
Nearer the equator, sunlight strikes Earth more directly.
在赤道附近,阳光更直接地袭击地球。
As a result, the land receives more heat and light.
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However, the migrations created a new problem.
然而,移徙造成了一个新的问题。
Early humans now living in colder places couldn’t produce as much vitamin D because their darker skin blocked too much sunlight.
早期人类生活在更冷的地方,
Over generations, their skin grew lighter and produced more vitamin D.
世代相传,它们的皮肤变得较轻并产生了更多的维生素D.
The farther north early humans migrated, the more important it was to their survival to have lighter skin.
更北端的早期人类迁徙, 越是重要,他们的生存 皮肤更轻。
Over the centuries, other migrations into different UV environments have taken place, and people with different skin pigmentation have had children together.
数个世纪以来,其他迁移到不同的紫外线环境,有不同皮肤色素的人一起生了孩子.
The result is the many variations in skin color among people today.
其结果是,今天人们的肤色有许多不同。
A mother gives drops of vitamin D to her infant.
母亲给婴儿一滴维生素D.
Today, even many people with pale skin don’t get enough vitamin D.
甚至许多皮肤苍白的人也得不到足够的维生素D。
Skin Pigmentation Conditions Certain conditions can affect skin color.
皮肤染色条件 某些条件会影响皮肤颜色
Albinism is caused by genes that reduce the amount of melanin formed in the body.
白素由基因所引起,可以减少体内所形成的黑色素的量.
The condition often results in very pale skin and white or pale blond hair.
病情往往导致皮肤非常苍白和白或苍白的金发.
People with albinism must make an extra effort to stay safe from UV radiation.
白化病患者必须作出额外努力,避免紫外线辐射。
Staying out of the sun, wearing protective clothing, and using sunscreen are all important.
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Albinism can also affect both the color and health of the eyes.
白化也可能影响眼睛的颜色和健康.
Blue eyes are most common, but they may be reddish, purple, hazel, or brown.
蓝色眼睛最常见,但可能为红色,紫色,色泽或棕色.
People with albinism often have vision problems that cannot be corrected with glasses.
白化病患者往往有视力问题,不能用眼镜来纠正.
Many are unable to drive.
许多人无法开车。
Albinism occurs around the world and can affect people of every ethnic background.
白化病在世界各地都发生,可以影响每个民族背景的人.
Vitiligo (vit-ih-LY-go) causes the skin to lose color in patches.
Vitiligo (vit-ih-LY-go)使皮肤在补丁中失去颜色.
It can affect many or just a few parts of the body.
它可以影响身体的许多部分或只是几个部分.
The direct cause of vitiligo is melanocytes dying or not working properly.
维蒂利戈的直接原因是黑色线虫死亡或工作不当.
However, no one knows why that happens.
然而,没有人知道为什么会这样。
Vitiligo is not dangerous, but it can cause a person to feel self-conscious.
维蒂利戈并不危险,但它会使一个人感到自觉.
It’s important for people with vitiligo to use sunscreen, too, since skin that has lost color can sunburn easily.
因为皮肤失色很容易被晒伤。
Another concern for people with vitiligo is partial hearing loss if the melanocytes in the inner ear are affected.
对有维蒂利戈人的另一个关切是,如果内耳的多肽受了影响,部分听力丧失.
Although vitiligo affects people with every skin color, its effects are more visible in those with dark skin.
虽然Vitiligo影响着每个肤色的人,但其影响在皮肤深色的人中更为明显.
Winnie Harlow overcame school bullies and years of rejection to achieve her dream of becoming a top fashion model.
温妮·哈洛克服了学校的欺凌和多年的拒绝,实现了她成为顶尖时尚模特的梦想.
Solving UV Mismatches As a result of thousands of years of human migration, many people no longer live in areas that their skin color is best suited for.
解决紫外线 错配 由于人类数千年的迁徙,许多人不再生活在最适合其肤色的地区.
People with darker skin who live in low-UV areas nearer the poles must be careful to get enough vitamin D.
皮肤更深的人,如果生活在更靠近柱子的低紫外线地区,必须注意获得足够的维生素D.
People with lighter skin who live in high-UV areas nearer the equator must protect their skin from too much UV-B radiation.
生活在赤道附近高紫外线地区的皮肤较轻的人必须保护皮肤免受紫外线-B辐射过多.
Fortunately, people are problem solvers.
幸运的是,人们是解决问题的人。
Sunscreen, sun-protective clothing, and vitamin D supplements address the problems caused by UV mismatches.
防晒霜、防晒衣和维生素D补充剂解决了紫外线不匹配造成的问题。
As both people and the world continue to change, we will no doubt keep coming up with new solutions.
随着人民和世界继续发生变化,我们无疑将继续提出新的解决办法。
As people learn more about how the Sun affects their skin, it’s easier to keep their skin happy!
当人们更多地了解太阳如何影响皮肤时,