14 Annelids: World of Worms-Mid

Annelids: World of Worms FOCUS Question How does a worm's body help it live in its habitat?

环节动物:蠕虫的世界焦点问题蠕虫的身体如何帮助它在栖息地生活?

Wriggly Worms You're digging in the garden when you discover something squirming in the soil. It's an earthworm! Earthworms belong to a group of worms called annelids The bodies of annelids. are organized into small segments, or sections. Segmented worms also include bristle worms and leeches. Annelids have long, flexible bodies. They are invertebrates, which means they don't have a backbone. They have no arms or legs, either. Worms are found in just about every habitat on Earth. They live on land and in water—even in ice!

你正在花园里挖土，突然发现有什么东西在土里蠕动。 这是蚯蚓!蚯蚓属于一种叫做环节动物的蠕虫。 被组织成小段或部分。 分节蠕虫还包括鬃虫和水蛭。 环节动物有长而灵活的身体。 它们是无脊椎动物，这意味着它们没有脊椎。 他们也没有胳膊和腿。 蚯蚓几乎可以在地球上的每一个栖息地找到。 它们生活在陆地和水中，甚至在冰里!

Digging in the Dirt An earthworm's name says it all—these segmented worms make their homes in the soil. Earthworms dig, burrow, and make tunnels in their earthy habitat. They live anywhere that has damp soil conditions. Many of them live in rainy forests or in places with lots of muck and mud. Earthworms breathe through their smooth, slimy skin. Their skin produces a slippery substance called mucus (MYOO-kuss). This coating of mucus helps keep their body moist. It also allows the worms to glide easily through the soil.

蚯蚓的名字就说明了一切——这些分节的蠕虫在土壤中安家。 蚯蚓在它们的泥土栖息地挖洞、挖洞、挖隧道。 它们生活在任何土壤潮湿的地方。 他们中的许多人生活在多雨的森林或有很多淤泥和泥浆的地方。 蚯蚓通过它们光滑黏滑的皮肤呼吸。 它们的皮肤会产生一种叫做粘液的光滑物质。 这层粘液有助于保持身体湿润。 它还可以让蠕虫轻松地在土壤中滑行。

Earthworms also have tiny bristles on each segment that help them move through the soil. These bristles are called setae (SEE-tee). To burrow, an earthworm moves its setae in and out so it can grip the ground. The worm's muscles then push its body forward. As it tunnels, an earthworm takes in soil, dead leaves, and decaying plant roots through its mouth. Then the worm breaks down the leftover living material and returns the nutrients to the soil as waste. Earthworms are helpful decomposers. Math Moment If an earthworm has 26 setae on one segment. and 100 segments how many setae does it have?

蚯蚓的每一节上都有细小的刚毛，帮助它们在土壤中移动。 这些刚毛叫做刚毛(SEE-tee)。 在挖洞时，蚯蚓将刚毛向内和向外移动，这样它就能抓住地面。 然后蠕虫的肌肉推动它的身体向前。 蚯蚓在挖隧道时，会通过嘴吸入土壤、枯叶和腐烂的植物根。 然后，蠕虫分解剩余的生物物质，将营养物质作为废物返回土壤。 蚯蚓是有益的分解者。 如果一条蚯蚓的一节上有26根刚毛。 100节有多少刚毛?

Bristles All Over Bristle worms are also known as polychaete (PAH-lee-keet) worms. Many swim in the open ocean or live on the ocean floor. Some live in fresh water. Others burrow in the sand on beaches. Bristle worms have a pair of parapodia (pare-uh-POH-dee-uh) on each segment of their body. These structures look like small legs. Each one has bristles on it. Parapodia help bristle worms move and survive in different kinds of environments. Word Wise Polychaete comes from the Greek language. Poly- means "many," and chaete means "bristles."

刚毛虫也被称为多毛虫(PAH-lee-keet)。 许多人在开阔的海洋中游泳或生活在海底。 有些生活在淡水中。有的则在沙滩上的沙子里挖洞。 刚毛虫身体的每个部分都有一对旁足(pare-uh-POH-dee-uh) 这些结构看起来像小腿。 每一个上面都有刚毛。 副足帮助刚毛虫在不同的环境中移动和生存。 Word Wise Polychaete来自希腊语。 Poly-意思是“许多”，chaete意思是“刚毛”。

Adapting to Every Environment The Pompeii worm lives in a tube near very hot deep-sea vents. The water is heated underground and enters the sea through openings on the ocean floor. The Pompeii worm's fuzzy body is covered with bacteria. The bacteria insulate the worm and protect it from the heat. This bristle worm has small parapodia. It uses them to move water around and get more oxygen into its tube home. The clam worm lives in shallow water, where it swims and crawls using its large, curved parapodia and often burrows in the mud. Clam worms eat other invertebrates and algae with their strong jaws.

庞贝蠕虫生活在非常热的深海喷口附近的管子里。 水在地下加热，通过海底的开口流入大海。 庞贝蠕虫毛茸茸的身体上布满了细菌。 细菌将蠕虫隔离起来，保护它免受高温。 这种刚毛虫有小的旁足。 它用它们来移动周围的水，让更多的氧气进入它的管道家园。 蛤蜊蠕虫生活在浅水中，在那里它游泳和爬行用它的大而弯曲的副足，经常在泥里挖洞。 蛤虫用它们强壮的下颚吃其他无脊椎动物和藻类。