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  • 生态系统中的能量流动

    Lesson Objectives
    ::经验教训目标

    • Define ecosystem and give examples.
      ::界定生态系统并举例说明。
    • Explain how energy flows through ecosystems.
      ::解释能源如何通过生态系统流动。
    • Outline how matter moves through ecosystems.
      ::概述物质如何在生态系统中流动。

    Lesson Vocabulary
    ::词汇表课程

    • carnivore
      ::食 食 食 食 食 食
    • community
      ::社区社区
    • consumer
      ::消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费 消费
    • decomposer
      ::脱混集器
    • ecosystem
      ::生态系统生态系统生态系统生态系统生态系统
    • food chain
      ::食物链食物链链
    • food web
      ::食物食物网
    • grazer
      ::草草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草 草
    • habitat
      ::生境生境
    • herbivore
      ::食 草 食 食 草
    • niche
      ::位数
    • nutrients
      ::营养养养
    • omnivore
      ::全民营养
    • population
      ::人口 人口 人口
    • predator
      ::食肉动物
    • prey
      ::猎物
    • producer
      ::生产商 生产者
    • scavenger
      ::拾荒者
    • species
      ::物种种类

    Introduction
    ::导言

    You open your front door and step outside. It doesn’t matter where you live, you are in your ecosystem. All around you are living and non-living things. You’re surrounded by air. You feel warm sunlight on your face. There’s soil under your feet. You see plants and hear a bird singing. Your own body is covered with billions of bacteria. All of these things are part of your ecosystem.
    ::你打开前门,走出门,不管你住在哪里,你住在你的生态系统里。你周围都是活的和非活的事物。你周围都是活的和非活的事物。你被空气包围着。你脸上有温暖的阳光。你脚下有温暖的阳光。你看到植物,听到鸟儿唱歌。你的身体里有数十亿细菌。所有这些东西都是你生态系统的一部分。

    What Is An Ecosystem?
    ::什么是生态系统?

    An  ecosystem  is a group of living things and their environment. The word ecosystem is short for “ecological system.” Like any system, an ecosystem is a group of parts that work together. You can see examples of ecosystems in  Figure   . The forest pictured is a big ecosystem. Besides trees, what living things do you think are part of the forest ecosystem? The dead tree stump in the same forest is a small ecosystem. It includes plants, mosses, and fungi. It also includes insects and worms.
    ::生态系统是生命物及其环境的组合。生态系统一词短于“生态系统 ” 。 与任何系统一样,生态系统是一组共同发挥作用的部分。您可以看到图中生态系统的例子。图中显示的森林是一个大生态系统。除了树木,你认为什么是生命物是森林生态系统的一部分?同一森林中死亡的树桩是一个小生态系统,它包括植物、藻类和真菌。它也包括昆虫和虫子。

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    An ecosystem can be big or small. A small ecosystem can be part of a larger ecosystem.
    ::生态系统可以是大生态系统,也可以是小生态系统,小生态系统可以是大生态系统的一部分。

    Roles in Ecosystems 
    ::在生态系统中的作用

    All ecosystems have living things that play a role. Plants produce food from sunlight. Other living things may eat plants to get energy. On and on, energy is allowed to flow from one living thing to another. All roles help energy flow through an ecosystem. What are these roles? 
    ::所有生态系统都有能发挥作用的生物。植物从阳光中生产食物。其他生物可以吃植物以获取能源。能源可以从一个生物向另一个生物流动。所有作用都有助于能源通过生态系统流动。这些作用是什么?

    Producers
    ::生产者 生产者

    Producers  are living things that use energy to make food. Producers make their own food. As well, other living things are able to eat them for food. As you have learned, plants are able to make their own food. To make their own food they use the energy from the Sun. 
    ::生产者是使用能源生产食物的活物,生产者是自己生产食物的。同样,其他活物也可以以食物为食物。正如你们所学的那样,植物可以自己生产食物。他们用太阳的能量生产自己的食物。

    Consumers
    ::消费者消费者

    Consumers  can’t make their own food. Consumers must eat other living things. They may eat plants or animals.  Figure    lists the three main types of consumers. Which type are you?
    ::消费者不能自己制造食物。 消费者必须吃其他生物。 他们可以吃植物或动物。 图中列出了三大类消费者。 你是哪类消费者?

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    Examples of the main types of consumers. Can you name other consumers of each type?
    ::消费者主要类型的例子。您能点出其他各类消费者的名字吗 ?

    Consumers get their food in different ways (see  Figure   ).  Grazers  feed on living organisms without killing them. A rabbit nibbles on leaves. A mosquito sucks a drop of blood.  Predators , like lions, capture and kill animals for food. The animals they eat are called  prey . Even some plants are consumers. Pitcher plants trap insects in their sticky fluid. The insects are their prey.  Scavengers  eat animals that are already dead. The hyena below is eating the remains of a lion’s prey. You may have also seen vultures eating along the roadside.  Decomposers  break down dead organisms and the wastes of living things. The dung beetle is rolling a ball of dung (animal waste) back to its nest. The beetle will use the dung to feed its young. The mushrooms pictured are growing on a dead log. They will slowly break it down. This releases its nutrients into the soil.
    ::食肉动物以不同方式获得食物(见图 ) 。 食草动物食用活生物体而不杀死它们。 一只兔子在叶子上吃东西。 一只蚊子吸血一滴血。 捕食者,像狮子一样,捕捉和杀死动物作为食物。 他们吃的动物被称为猎物。 甚至有些植物也是消费者。 捕食者将昆虫放入粘粘液中。 昆虫是它们的猎物。 食肉动物吃已经死亡的动物。 下面的野狼正在吃掉狮子猎物的残渣。 你们可能也看到秃鹫在路边吃东西。 食肉动物把死生物体和生物垃圾分解开来。 虫正在把一只粪便球(动物粪便)滚回巢中。 蜜虫会用粪便喂幼。 所拍摄的蘑菇正在生长在枯原上, 它们会慢慢地粉碎, 慢慢地粉碎。

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    Ways consumers get food. Do you know how earthworms get food?
    ::消费者如何获得食物 你知道蚯蚓如何获得食物吗?

    How Energy Flows Through Ecosystems
    ::如何通过生态系统进行能源流动

    All living things need energy. They need it to power the processes of life. For example, it takes energy to grow. It also takes energy to produce offspring. In fact, it takes energy just to stay alive. Remember, energy can’t be created or destroyed. It can only change form. Energy changes form as it moves through ecosystems. 
    ::所有生物都需要能源,它们需要能源来给生命过程提供动力。例如,它需要能源来培育后代。事实上,它只需要能源来维持生命。记住,能源不能创造或摧毁。它只能改变形态。随着生态系统的演变,能源会变化。

    The Flow of Energy
    ::能源流动

    Most ecosystems get their energy from the Sun. Only producers can use sunlight to make food. Producers convert the sunlight into chemical energy or food. Consumers get some of that energy when they eat producers. They also pass some of the energy on to other consumers when they are eaten. In this way, energy flows from one living thing to another.
    ::大部分生态系统的能源来自太阳。 只有生产者才能利用阳光生产食物。 生产者将阳光转化为化学能源或食品。 消费者在吃生产者时获得部分能源。 当他们被吃掉时,他们也将部分能源传递给其他消费者。 这样,能源从一种生物流向另一种生物。

    Food Chains
    ::食物链链

    A  food chain  is a simple diagram that shows one way energy flows through an ecosystem. You can see an example of a food chain in  Figure   . Producers form the base of all food chains. The consumers that eat producers are called primary consumers. The consumers that eat primary consumers are secondary consumers. This chain can continue to multiple levels.
    ::食物链是一个简单的图表,它显示了能源通过生态系统的一种方式。您可以看到图中的食物链的例子。 生产者构成所有食物链的基础。 食用生产者的消费者被称为初级消费者。 食用初级消费者的消费者是次级消费者。 这个链可以持续到多个层次。

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    What do the arrows stand for in a food chain?
    ::箭头在食物链中代表什么?

    At each level of a food chain, a lot of energy is lost. Only about 10 percent of the energy passes to the next level. Where does that energy go? Some energy is given off as heat. Some energy goes into animal wastes. Energy also goes into growing things that another consumer can't eat, like fur. It's because so much energy is lost that most food chains have just a few levels. There’s not enough energy left for higher levels.
    ::在食物链的每一个层次上,能源都会大量流失。只有大约10%的能源流向下一个层次。能源流向哪里?能源流向哪里?一些能源作为热能被释放出来。一些能源流入动物废物中。能源还进入了另一个消费者无法吃的生长中,比如毛皮。这是因为能源大量流失,大多数食物链只有几个层次。没有足够的能源可用于更高的水平。

    Food Webs
    ::食品网

    Food chains are too simple to represent the real world. They don’t show all the ways that energy flows through an ecosystem. A more complex diagram is called a  food web . You can see an example in  Figure   . A food web consists of many overlapping food chains. Can you identify the food chains in the figure? How many food chains include the mouse?
    ::食物链太简单,无法代表真实世界。 它们没有显示能源通过生态系统的所有方式。 一个更复杂的图表被称为食物网。 您可以在图中看到一个例子。 食物网由许多重叠食物链组成。 你能识别数字中的食物链吗? 有多少食物链包括鼠标?

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    The owl in this food web consumes at two different levels. What are they?
    ::这个食物网中的猫头鹰消耗了两个不同层次。它们是什么?

    How Matter Moves Through Ecosystems
    ::物质如何在生态系统中移动

    Living things need non-living matter as well as energy. What do you think matter is used for? One thing is to build bodies. They also need it to carry out the processes of life. Any non-living matter that living things need is called a  nutrient . Carbon and nitrogen are examples of nutrients. Unlike energy, matter is recycled in ecosystems. You can see how in  Figure   .
    ::生命需要非生物物质和能量。 你认为物质是用来做什么的? 一件事是建立身体。 它们也需要它来进行生命过程。 任何非生物物质需要的东西都被称为养分。 碳和氮是养分的例子。 与能源不同,物质在生态系统中被回收。 您可以在图中看到。

    • Decomposers release nutrients when they break down dead organisms.
      ::分解器在分解死亡生物时释放养分
    • The nutrients are taken up by plants through their roots.
      ::植物通过根部吸收养分
    • The nutrients pass to primary consumers when they eat the plants.
      ::养分在主要消费者吃植物时传递给他们。
    • The nutrients pass to higher level consumers when they eat lower level consumers.
      ::养分在消费较低水平的消费者时传递给较高层次的消费者。
    • When living things die, the cycle repeats.
      ::当生命死去时 循环会重复

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    This diagram shows two cycles. One is the cycle of energy, the other is the cycle of matter. Compare the two cycles. Do you see how the Sun keeps adding energy? That’s because energy is lost at each step of the cycle. Matter doesn’t have to be added. Can you explain why?
    ::这个图表显示了两个周期。 一个是能源循环, 另一个是物质循环。 比较两个周期。 你是否看到太阳是如何增加能源的? 这是因为能源在周期的每一个阶段都丧失了。 物质不需要添加。 你能解释为什么吗?

    Lesson Summary
    ::经验教训摘要

    • Biotic factors are the living parts of ecosystems. They include species of living things.
      ::生物因素是生态系统的活部分,包括生物物种。
    • All ecosystems have organisms that play the same roles. They all have producers and consumers.
      ::所有生态系统都有发挥相同作用的有机体,所有生态系统都有生产者和消费者。
    • All living things need energy. Most ecosystems get energy from the Sun. Producers use the energy to make food. They pass some of the energy to consumers. Food chains and food webs show how energy flows through ecosystems.
      ::所有生物都需要能源。大多数生态系统从太阳获得能源。生产者利用能源生产粮食。他们将一些能源传给消费者。食物链和食物网显示了能源如何通过生态系统流动。
    • Living things also need matter. Unlike energy, matter is recycled in ecosystems.
      ::生命也需要物质。与能源不同,物质在生态系统中被循环利用。

    Lesson Review Questions
    ::经验回顾问题

    Recall
    ::回顾

    1. Identify three types of consumers, based on what they eat.
      ::根据消费者的饮食情况,确定三类消费者。
    1. Give an example of each of these types of organisms: predator, scavenger, and decomposer.
      ::举例说明其中每一种生物:食肉动物、食肉动物、食腐动物和脱腐动物。
    1. What is a nutrient?
      ::什么是养分?

    Apply Concepts
    ::应用概念

    1. Draw an energy flow diagram that consists of the following organisms: fox, grass, mountain lion, and rabbit. 
      ::绘制由以下生物组成的能量流图:狐狸、草、山狮和兔子。