49 Extreme Environments-Mid

Extreme Environments FOCUS Question How do organisms survive in extreme environments?

极端环境焦点问题生物如何在极端环境中生存?

Beyond the Ordinary Rainforests, grasslands, oceans, and deserts are just some of Earth's key ecosystems. Each one is unique and is home to many kinds of organisms. But some environments are so extreme? that only certain organisms can live there. What makes an environment extreme It may be boiling hot or freezing cold. It may be filled with salt or be completely dark. It may be waterlogged or arid. The plants and animals that live in these extreme environments have special adaptations that help them survive. These amazing creatures are called extremophiles.

除了普通的雨林，草原、海洋和沙漠只是地球上一些重要的生态系统。 每一个都是独一无二的，是多种生物的家园。 但有些环境是如此极端? 只有特定的生物才能在那里生存。 是什么让环境变得极端?可能是滚烫，也可能是冰冷。 它可能装满了盐，也可能完全是黑色的。 它可能积水或干旱。 生活在这些极端环境中的植物和动物有特殊的适应能力来帮助它们生存。 这些神奇的生物被称为嗜极生物。

Severely Salty The Dead Sea is located on the border between Jordan and Israel. The water is too salty for most organisms to survive. A few kinds of bacteria are the only organisms that can live there. Earth's oceans are salty (but not as salty as the Dead Sea!). Marine iguanas live on the Galapagos Islands, off the coast of Ecuador. They feed on algae growing in the ocean. As these iguanas eat, they swallow salt. Too much salt in their bodies would kill them. These lizards have special glands that filter salt from their blood. Then they sneeze the salty liquid out through their nostrils!

死海位于约旦和以色列的边界上。 水太咸了，大多数生物无法生存。 只有几种细菌能在那里生存。 地球上的海洋是咸的(但没有死海那么咸!) 海鬣蜥生活在厄瓜多尔海岸外的加拉帕戈斯群岛。 它们以生长在海洋中的藻类为食。 这些鬣蜥吃东西时会吞下盐。 过多的盐会杀死它们。 这些蜥蜴有特殊的腺体，可以过滤血液中的盐分。 然后它们从鼻孔里把含盐的液体打喷嚏出去!

Too Cold or Too Hot Some creatures have to adapt to living in an extremely cold or hot environment. The wood frog has adapted to chilly conditions. When the temperature dips below freezing. so does most of the water inside the frog's body. In this state, the frog doesn't breathe. It doesn't even have a heartbeat! When the weather warms up, so does the frog. At the other extreme, fennec foxes live in the scorching Sahara Desert in North Africa. Their oversized ears release body heat and help keep the foxes cool.

太冷或太热有些生物必须适应在极冷或极热的环境中生存。 林蛙已经适应了寒冷的环境。 当温度降到冰点以下时。 青蛙体内的大部分水分也是如此。 在这种状态下，青蛙不呼吸。 它甚至没有心跳!当天气变暖时，青蛙也会变暖。 在另一个极端，耳廓狐生活在北非酷热的撒哈拉沙漠。 它们超大的耳朵释放身体热量，帮助狐狸保持凉爽。

Too Wet or Too Dry Too much water can be hard on plants and animals. But mangrove trees have adapted to live in waterlogged soil. Special roots grow in the air and act like snorkels. They get the oxygen the tree needs, even when the tide is high. Too little moisture can also be a problem for most living things. However, the tiny tardigrade can survive with no water at all! During dry times, it curls up into a ball called a tun (rhymes with "sun"). The water in its body is replaced with a special sugar that keeps it alive. When water is available again, the tardigrade uncurls and swims away.

太湿或太干太多的水会给植物和动物带来困难。 但是红树林已经适应了在积水的土壤中生存。 特殊的根生长在空气中，起着通气管的作用。 即使在涨潮时，它们也能获得树木所需的氧气。 湿度过低对大多数生物来说也是一个问题。 然而，这种微小的缓步动物在没有水的情况下也能生存!在干旱的季节，它会卷曲成一个球，叫做大桶(与“太阳”押韵)。 它体内的水被一种特殊的糖所取代，这种糖能维持它的生命。 当水再次出现时，水熊虫就会展开身体游走。

Complete Darkness Most caves are completely dark. With no sunlight, there is no need for animals to have vision or be colorful. Over many generations, some creatures that live in caves have lost their eyesight and body color. Mexican cave fish have no color and no eyes. They don't need to see in order to catch their food. These fish have a strong sense of smell. They can also sense tiny pressure changes in the water. These abilities help cave fish find food and survive in complete darkness. Do You Know? It takes energy for an organism to produce body color, or pigment. In total darkness, animals save this energy because they don't need color for protection or camouflage.

完全黑暗大多数洞穴都是完全黑暗的。 没有阳光，动物就不需要有视力或色彩鲜艳。 经过许多代，一些生活在洞穴里的生物已经失去了他们的视力和身体颜色。 墨西哥洞穴鱼没有颜色，也没有眼睛。 它们不需要看就能捕捉到食物。 这些鱼的嗅觉很灵敏。 它们还能感知水中微小的压力变化。 这些能力帮助洞穴鱼在完全黑暗的环境中寻找食物和生存。 你知道吗?生物体产生身体颜色或色素需要能量。 在完全黑暗的环境中，动物节省能量，因为它们不需要颜色来保护或伪装。