38 Inheriting Stripes-Mid

Inheriting Stripes FOCUS Question How do animals develop stripes?

遗传条纹焦点问题动物是如何形成条纹的?

So Many Stripes Many animals have a striped body. Zebras have bold black-and-white stripes, and tigers have bands of black and orange. Some fish, insects, and reptiles flash blue, green, red, and yellow stripes. Ring-tailed lemurs, raccoons, and some birds have striped parts, too. Even your pet cat may have stripes.

许多动物的身体都有条纹。 斑马有醒目的黑白条纹，老虎有黑色和橙色的条纹。 有些鱼、昆虫和爬行动物会闪着蓝色、绿色、红色和黄色的条纹。 环尾狐猴、浣熊和一些鸟类也有条纹。 甚至你的宠物猫也可能有条纹。

Why Stripes? Stripes look like simple decorations, but they help an animal in important ways. Stripes may make it hard for a predator to single out one zebra in a large group. They also help tigers blend in with the shadows of trees or tall grass. In both cases stripes help to camouflage (CA-muh-flahj) the animal. Stripes help other animals stand out. Coral snakes have colored stripes that warn animals about their venomous bite. Skunks also have bold stripes as an alert to other animals. So how do animals develop stripes? Do You Know? Stripes may also help protect zebras from flies that bite. Scientists think the flies cannot see the stripes, so they don't land on zebras.

为什么条纹?条纹看起来像简单的装饰，但它们在重要的方面帮助了动物。 条纹可能会让捕食者很难在一大群斑马中挑出一匹。 它们还能帮助老虎融入树木或高草的阴影中。 在这两种情况下，条纹有助于伪装(CA-muh-flahj)动物。 条纹可以帮助其他动物脱颖而出。 珊瑚蛇身上有彩色的条纹，可以警告动物它们有毒的咬伤。 臭鼬身上也有醒目的条纹，作为对其他动物的警告。 那么动物是如何形成条纹的呢? 你知道吗?条纹也可以帮助保护斑马免受苍蝇叮咬。 科学家认为苍蝇看不到条纹，所以它们不会落在斑马身上。

Traits A trait is a physical feature or behavior. An animal's color is a trait. Height is a trait. Being able to run fast is another trait. Stripes are also a trait. Living things get many of their traits from their parents. They inherit the traits. One trait that animals inherit is color. The colors of an animal's fur, scales, or other body covering come from pigments. A pigment is any chemical that gives off a color. Pigments usually make dark colors, but they can also create bright colors. Science in Your World Most mammals have a pigment called melanin. This chemical can create many colors, from black to brown to red. The pigment in a zebra's stripes is the same pigment as in human skin.

trait是一种身体特征或行为。 动物的颜色是一种特征。 身高是一种特征。跑得快是另一个特点。 条纹也是一种特征。生物的许多特征都来自于它们的父母。 他们继承了这些特征。动物遗传的一个特征是颜色。 动物皮毛、鳞片或其他身体覆盖物的颜色来自色素。 色素是任何能发出颜色的化学物质。 颜料通常会产生深色，但也能产生亮色。 大多数哺乳动物都有一种叫做黑色素的色素。 这种化学物质可以产生多种颜色，从黑色到棕色到红色。 斑马条纹中的色素与人类皮肤中的色素相同。

Pigments are made inside the cells of an animal's skin. Cells are the tiny parts that make up all living things. The pigments add color to the animal's fur, feathers, or scales. Some skin cells make a lot of pigment, which produces dark areas. Other skin cells make less pigment, which produces light areas. Some skin cells make no pigment at all. These areas are white. The amount of pigment an animal has is a trait that it inherits from its parents. An animal with dark fur will likely have babies with dark fur. In some animals like zebras, the pigment-making cells all line up together. They form stripes The cells in the dark stripes make a lot of pigment. The cells in the light stripes do not.

色素是在动物皮肤细胞内产生的。 细胞是构成所有生物的微小部分。 这些色素为动物的皮毛、羽毛或鳞片增添颜色。 一些皮肤细胞会产生大量色素，从而产生深色区域。 其他皮肤细胞产生的色素较少，从而产生浅色区域。 有些皮肤细胞根本不产生色素。 这些区域是白色的。动物身上的色素数量是遗传自父母的一种特征。 深色皮毛的动物可能会生出深色皮毛的宝宝。 在斑马等动物体内，色素生成细胞全部排列在一起。 黑色条纹中的细胞产生大量色素。 浅色条纹中的细胞则不然。

How Stripes Form A baby zebra inherits a striped pattern from its parents. The pattern forms as the baby zebra grows inside its mother. But each zebra is not an exact copy of its parents. Every zebra's stripes vary a little, as human fingerprints do. How do some cells make pigment and other cells don't? How do the cells line up and form stripes? How can a pattern be inherited but also be different? Scientists are still trying to answer these questions. Read on to find out how they think it works.

条纹是如何形成的斑马宝宝从父母那里遗传了条纹图案。 这种图案是斑马宝宝在妈妈肚子里长大时形成的。 但每只斑马都不是其父母的精确副本。 每只斑马的条纹都略有不同，就像人类的指纹一样。 为什么有些细胞会产生色素，而有些细胞则不会? 细胞是如何排列并形成条纹的? 一种模式如何既能被继承，又能与众不同? 科学家们仍在试图回答这些问题。 往下读，看看他们是怎么想的。