41 Pollywogs and Friends-Mid

Pollywogs and Friends FOCUS Question How does an amphibian's body change as it develops?

两栖动物的身体在发育过程中是如何变化的?

Meet the Amphibians Visit almost any pond and you might spot some odd-looking animals swimming around. They have round heads and short tails. These aren't fish. They are tadpoles, also known as pollywogs. Pollywogs are young amphibians (am-FIH-bee-unz)— animals that live part of their lives in water and part of their lives on land. Amphibians have moist skin. Some can even breathe through their skin. Frogs, toads, salamanders, and newts are all amphibians.

参观几乎任何一个池塘，你都可能看到一些长相怪异的动物在周围游泳。 他们有圆形的头和短尾巴。 这些不是鱼。它们是蝌蚪，也被称为蝌蚪。 波利沃格是一种年轻的两栖动物(am-FIH-bee-unz)，它们一部分生活在水中，一部分生活在陆地上。 两栖动物有湿润的皮肤。 有些甚至可以通过皮肤呼吸。 青蛙、蟾蜍、蝾螈和蝾螈都是两栖动物。

Amphibian Life Cycle Most amphibians begin life as pollywogs and hatch from eggs. Pollywogs live in water. As they grow, they go through metamorphosis. This means they change shape as they become adults. Most adult amphibians come out of the water and live on land. But they always go back near the water to lay eggs. The eggs must stay wet so they can hatch. Word Wise The word metamorphosis comes from the Greek language. Meta- means "change." -morph- means "shape," and -osis means a "process"

大多数两栖动物都是由卵孵化而成。 波利沃格生活在水里。随着它们的生长，它们会经历蜕变。 这意味着它们在成年后会改变形状。 大多数成年两栖动物从水里出来，生活在陆地上。 但它们总是回到靠近水边的地方产卵。 卵必须保持湿润才能孵化。 metamorphosis这个词来自希腊语。 Meta-意思是“改变”。-morph-意思是“形状”，-osis是“过程”

Eggs and Gills Amphibians lay eggs in ponds, marshes, swamps, or puddles. Some lay eggs that are covered with a jellylike material. The jelly helps keep the eggs safe. Others attach the eggs to underwater plants so they are hidden from animals that might eat them. In rainforests, some amphibians lay their eggs in small pools of water trapped by plant leaves. After a few weeks, pollywogs hatch from the eggs. Pollywogs have gills that let them breathe in water. Sometimes, the gills grow on the outside of their head. They look like a feathery decoration.

卵和鳃两栖动物在池塘、沼泽、沼泽或水坑中产卵。 有些产卵时，蛋上覆盖着一层胶状物质。 这种果冻有助于保证蛋的安全。 另一些人则把卵附着在水下植物上，这样它们就不会被动物吃掉了。 在雨林中，一些两栖动物将卵产在被植物叶子困住的小水池里。 几周后，小波龙从卵中孵化出来。 波利沃格有让它们在水中呼吸的鳃。 有时，鳃长在头部的外侧。 它们看起来像羽毛装饰。

Eat and Be Eaten Pollywogs eat almost anything in the water. They eat water plants. They also eat dead animals. A few kinds of pollywogs have teeth. They use them to hunt for underwater insects or small fish. Many animals eat pollywogs. Fish, birds, turtles, and even large insects might try to grab one from the water. Pollywogs swim away fast by wiggling their tails. They also stay in groups to stay safe. But many are still eaten. A typical amphibian lays hundreds of eggs at one time. Only some of the pollywogs survive.

吃和被吃波利沃格几乎吃水里的任何东西。 它们吃水生植物。他们也吃死去的动物。 少数种类的多蜥有牙齿。 它们用它们来捕食水下昆虫或小鱼。 许多动物吃多角虫。 鱼、鸟、乌龟，甚至是大昆虫都可能试图从水里抓一个。 波利沃格通过摆动尾巴快速游走。 它们也成群结队以保证安全。 但很多还是被吃掉了。典型的两栖动物一次产卵数百个。 只有一些波利沃格存活下来。

Metamorphosis The pollywogs grow quickly. After a few weeks, they start metamorphosis. Pairs of legs begin to grow out of their body. In some amphibians the tail gets shorter and shorter. But in others, the tail remains into adulthood. The pollywogs also grow lungs. Now they begin to breathe air. After the legs and lungs are fully developed, the adults can come out of the water. The animals move around on land.

变形蜥长得很快。 几周后，它们开始变形。 成对的腿开始从他们的身体里长出来。 有些两栖动物的尾巴越来越短。 但在其他动物中，尾巴一直保留到成年。 波里沃格也会长出肺。 现在他们开始呼吸空气。 在腿和肺发育完全后，成鱼就可以出水了。 动物们在陆地上活动。