📚 Common Misconceptions in Year 7 CIE Biology and How to Correct Them | Year 7 CIE 生物常见误区与纠正方法
Biology at Year 7 introduces many fascinating ideas, but it also brings several persistent misunderstandings. Some of these come from everyday language, others from partial observations. Addressing them early builds a solid foundation for IGCSE and beyond. In this article, we will examine ten common misconceptions that Year 7 CIE learners often hold, explain why they are incorrect, and provide clear, accurate explanations for each.
七年级的生物课引入了许多迷人的概念，但也带来了一些根深蒂固的误解。有些误解来自日常用语，有些则源于片面的观察。尽早解决这些问题，能为 IGCSE 及更高阶段的生物学习打下坚实基础。在本文中，我们将探讨 Year 7 CIE 学生常常抱有的十个常见误区，说明它们为什么是错误的，并逐条给出清晰准确的解释。
1. Breathing and Respiration Are the Same Thing | 呼吸与呼吸作用是一回事
Many students use the words "breathing" and "respiration" interchangeably. They think that both simply mean taking in air. This is a very common misunderstanding, especially because we talk about "respiratory system" for the lungs.
很多学生混用“呼吸”和“呼吸作用”这两个词。他们认为两者都只是指吸入空气。这是一个非常普遍的误解，尤其因为我们在谈论肺部时用的是“呼吸系统”这个词。
iving cell. In respiration, glucose and oxygen are used to release energy. At Year 7, we learn the simple summary: glucose + oxygen → energy + carbon dioxide + water. Breathing brings in the oxygen and removes the carbon dioxide, but respiration itself occurs in cells, not in the lungs.
呼吸是空气进出肺部的物理运动。而呼吸作用则是发生在每一个活细胞内部的化学过程。在呼吸作用中，葡萄糖和氧气被用来释放能量。在七年级，我们学习的简单概括是：葡萄糖 + 氧气 → 能量 + 二氧化碳 + 水。呼吸运动把氧气带进来并把二氧化碳排出去，但呼吸作用本身发生在细胞里，而不是肺部。
2. All Bacteria Are Harmful Germs | 所有细菌都是有害的病菌
When students hear the word "bacteria", they immediately think of diseases, dirt, and danger. Advertisements for cleaning products often reinforce this idea. It leads many learners to believe that bacteria are always bad.
当学生听到“细菌”这个词，他们会立刻联想到疾病、污垢和危险。清洁用品的广告常常强化这一观念。这导致许多学生认为细菌总是不好的。
In reality, the vast majority of bacteria are harmless, and many are extremely useful. Bacteria in our intestines help with digestion and produce vitamins. Decomposer bacteria break down dead plants and animals, recycling nutrients into the soil. Some bacteria are used to make yogurt and cheese. Only a small fraction of bacteria are pathogenic, meaning they cause disease. Understanding this balance is a key part of the Year 7 ecosystem and health topics.
事实上，绝大多数细菌是无害的，而且很多非常有用。我们肠道里的细菌帮助消化并制造维生素。分解者细菌能分解动植物的尸体，把营养物质循环回土壤。有些细菌被用来制作酸奶和奶酪。只有一小部分细菌是致病的，即会引起疾病。理解这种平衡是七年级生态系统和健康主题的关键内容。
3. Plants Only Respire at Night | 植物只在夜间进行呼吸作用
Because photosynthesis uses carbon dioxide and releases oxygen during the day, students frequently assume that plants do not respire in the light. They imagine that respiration is something plants do only when it is dark.
由于光合作用在白天消耗二氧化碳并释放氧气，学生经常以为植物在光下不进行呼吸作用。他们想象呼吸作用是植物只在黑暗时才做的事情。
Plants respire all the time, day and night. Respiration releases energy from glucose, and plants need that energy continuously for growth, repair, and other life processes. In daylight, photosynthesis usually produces more oxygen than respiration uses, so we observe a net release of oxygen. But the individual cells of the plant are carrying out both photosynthesis and respiration simultaneously. Remembering this helps avoid confusion when studying gas exchange in plants.
植物全天候都在进行呼吸作用，不分昼夜。呼吸作用从葡萄糖中释放能量，而植物需要持续不断的能量来进行生长、修复和其他生命活动。在白天，光合作用产生的氧气通常多于呼吸作用消耗的氧气，所以我们观察到净释放氧气。但植物体内的单个细胞是同时进行光合作用和呼吸作用的。记住这一点有助于避免学习植物气体交换时产生混淆。
4. Food Chains Show Everything an Animal Eats | 食物链显示了一种动物吃的所有食物
Early learners often think a food chain is like a menu describing every food source for an animal. They try to draw a single straight line that includes all possible prey for one predator, which leads to confusion when arrows are used.
早期的学生常常以为食物链就像菜单一样描述了一个动物的所有食物来源。他们试图画出一条单一的直线，包含一个捕食者所有可能的猎物，这在使用箭头时会带来混淆。
fox. It does not show that the fox also eats mice or that the rabbit eats various plants. To show multiple feeding connections, we use a food web. In Year 7 CIE, students learn to interpret and construct simple food chains and webs, always remembering that the arrow means "is eaten by" and points in the direction of energy transfer.
一条食物链只表示能量从生产者到顶级消费者的一条传递路径。例如：草 → 兔子 → 狐狸。它并不显示狐狸也吃老鼠，或兔子吃各种不同的植物。要展示多个捕食关系，我们使用食物网。在CIE七年级，学生学习解读和构建简单的食物链和食物网，始终记住箭头意为“被...所吃”，并且指向能量传递的方向。
5. All Organisms Require Oxygen to Survive | 所有生物都需要氧气才能生存
Animals' visible breathing reinforces the notion that life depends completely on oxygen. Students frequently declare that without oxygen, no living thing could exist. This idea is mostly true for animals but fails when we consider the microscopic world.
动物显而易见的呼吸运动强化了生命完全依赖氧气的观念。学生经常声称，没有氧气，任何生物都无法生存。这个想法对于动物来说大体正确，但当我们考虑微观世界时就不成立了。
Many microorganisms, especially certain bacteria and archaea, can live in environments completely lacking oxygen. They carry out anaerobic respiration or fermentation to obtain energy. Even human muscle cells can perform anaerobic respiration for a short time during intense exercise, producing lactic acid. In Year 7, we touch upon this when discussing yeast and its ability to respire without oxygen, producing carbon dioxide and alcohol. This is a simple yet powerful correction to the "oxygen for all life" myth.
许多微生物，特别是某些细菌和古菌，可以在完全缺乏氧气的环境中生存。它们进行无氧呼吸或发酵来获取能量。即使是人类的肌肉细胞，在剧烈运动时也能短时间进行无氧呼吸，产生乳酸。在七年级，我们在讨论酵母及其无氧呼吸能力（产生二氧化碳和酒精）时会涉及到这一点。这是对“所有生命都需要氧气”这一神话简单而有力的纠正。
6. Photosynthesis Happens Only in Leaves | 光合作用只在叶片中进行
Since textbooks always show a large green leaf as the site of photosynthesis, students quickly conclude that leaves are the only photosynthetic organs. This seems logical, but it oversimplifies plant anatomy.
由于教科书总把一片大绿叶作为光合作用的场所，学生很快得出结论，叶子是唯一进行光合作用的器官。这看似合理，但过度简化了植物的结构。
Any green part of a plant contains chlorophyll and can photosynthesise. Stems of many plants, especially green herbaceous stems, carry out photosynthesis. Unripe fruits are often green and perform photosynthesis as well. Even some roots exposed to light can turn green and photosynthesise. In Year 7, it is useful to remember that chlorophyll is the key, and chlorophyll is found not only in leaves but also in other green tissues.
植物的任何绿色部分都含有叶绿素，并能进行光合作用。许多植物的茎，特别是绿色的草本茎，都能进行光合作用。未成熟的果实通常是绿色的，也能进行光合作用。甚至一些暴露在光照下的根也会变绿并进行光合作用。在七年级，应当牢记叶绿素是关键，而且叶绿素不仅存在于叶片，也存在于其他绿色组织中。
7. Chromosomes and Genes Are the Same Thing | 染色体和基因是同一回事
Words like "gene" and "chromosome" are often used loosely in popular media, causing pupils to think they are two names for the same structure. They say things like "we inherit chromosomes from parents" without distinguishing the levels of organisation.
大众媒体常常随意使用“基因”和“染色体”这些词，导致学生以为它们是同一结构的两种叫法。他们会说“我们从父母那里遗传了染色体”，而没有区分组织的层次。
Chromosomes are long, coiled strands of DNA found in the nucleus of a cell. Each chromosome contains many genes. A gene is a small section of DNA that codes for a particular characteristic, such as eye colour or blood type. Humans have 46 chromosomes (23 pairs) in most cells, but they have about 20,000–25,000 genes. In Year 7, students learn that chromosomes are made of DNA, and genes are segments on these chromosomes. Keeping these scales clear is essential for later genetics work.
染色体是存在于细胞核中的长链DNA，呈螺旋状。每条染色体上含有很多个基因。基因是一小段DNA，它编码某个特定的性状，比如眼睛颜色或血型。人体大多数细胞中有46条染色体（23对），但却有大约20,000–25,000个基因。在七年级，学生学到染色体由DNA构成，而基因是这些染色体上的片段。清楚区分这些尺度对以后的遗传学学习至关重要。
8. Energy Can Be Recycled in an Ecosystem | 能量可以在生态系统中循环使用
Many students assume that energy flows in circles, just like materials such as water and carbon. They see a food web and imagine that energy goes round and round, being used again and again. This is a deep misconception rooted in confusing matter with energy.
许多学生认为能量是循环流动的，就像水和碳等物质一样。他们看到食物网，就想象能量在其中一圈一圈地转，一遍又一遍地被使用。这是一个深层次的误解，根源在于混淆了物质与能量。
In an ecosystem, matter is recycled, but energy flows in one direction. Energy enters most ecosystems as sunlight, is captured by producers during photosynthesis, and then passes along food chains to consumers. At each step, much of the energy is lost as heat through respiration. Eventually, all the energy is lost from the ecosystem as heat, so it must constantly be replenished by the Sun. This is why we say energy flows, while nutrients cycle. Year 7 students should be able to distinguish between these two fundamentally different processes.
在生态系统中，物质是循环的，但能量是单向流动的。能量大多以阳光的形式进入生态系统，被生产者在光合作用中捕获，然后沿着食物链传递给消费者。在每一环节，大部分能量都通过呼吸作用以热的形式散失。最终，所有能量都从生态系统中以热的形式散失，因此必须不断地由太阳补充。这就是为什么我们说能量流动，而营养物质则进行循环。七年级学生应能够区分这两个根本不同的过程。
9. A Species is Simply a Group of Animals That Look Alike | 物种就是一群长相相似的动物
Young learners often define a species by appearance. If two organisms look similar, they are assumed to belong to the same species. This gets them into trouble when considering breeds of dog, or different types of birds that appear similar.
年轻的学生常常以外貌来定义一个物种。如果两种生物看起来很像，他们就会认为它们属于同一物种。当他们考虑到不同品种的狗，或者看起来相似的不同鸟类时，这种想法就会带来麻烦。
The biological species concept states that a species is a group of organisms that can interbreed to produce fertile offspring. For example, all domestic dogs—from chihuahuas to Great Danes—belong to the same species because they can mate and produce puppies that are themselves fertile. However, a horse and a donkey look somewhat alike but produce a mule, which is sterile, so they are different species. In Year 7, students begin to appreciate that reproduction, not just looks, defines a species.
生物学物种概念指出，物种是指能够相互交配并产生可育后代的一群生物。例如，所有家犬——从吉娃娃到大丹犬——都属于同一个物种，因为它们可以交配并生下能够继续繁衍的小狗。然而，马和驴看起来有些相似，但交配后产生的骡子是不育的，所以它们属于不同物种。在七年级，学生开始认识到繁衍能力才是定义物种的关键，而不仅仅是外表。
10. All Cells Have a Nucleus | 所有细胞都有细胞核
When students first see typical animal and plant cell diagrams with a clearly marked nucleus, they store this image as the universal cell model. They often then insist that every cell must contain a nucleus. This is a very common error.
当学生第一次看到带有明显标记的典型动植物细胞图时，他们就把这个形象当作通用的细胞模型。他们之后经常坚持认为每个细胞都必须有一个细胞核。这是一个非常常见的错误。
Many cells do not have a nucleus. Bacteria are single-celled organisms that lack a nucleus; their DNA floats freely in the cytoplasm. Such cells are called prokaryotic. In the human body, mature red blood cells also lose their nucleus to make more space for haemoglobin. In Year 7, introducing the distinction between eukaryotic cells (with nucleus) and prokaryotic cells (without nucleus) prevents this misconception from becoming fixed. Students learn that the presence of a nucleus is a feature of plant and animal cells, but not of all life.
很多细胞并没有细胞核。细菌是单细胞生物，没有细胞核；它们的DNA自由漂浮在细胞质中。这样的细胞称为原核细胞。在人体内，成熟的红细胞也失去了细胞核，以便为血红蛋白腾出更多空间。在七年级，介绍真核细胞（有核）与原核细胞（无核）的区别，可以防止这一误解根深蒂固。学生将学到，拥有细胞核是动植物细胞的特征，但并非所有生物都如此。
11. Arteries Always Carry Oxygenated Blood | 动脉总是输送含氧血
Colour-coded diagrams often colour arteries red and veins blue, leading students to the rule: arteries carry oxygen-rich blood, veins carry oxygen-poor blood. They then apply this rule without exceptions, which is incorrect.
用颜色编码的图表常常把动脉涂成红色，静脉涂成蓝色，使学生得出一个规则：动脉输送富氧血，静脉输送贫氧血。他们随后毫无例外地应用这条规则，这是不正确的。
The correct definition is that arteries carry blood away from the heart, while veins carry blood towards the heart. Most arteries do carry oxygenated blood, but there are important exceptions. The pulmonary artery carries deoxygenated blood from the heart to the lungs. Likewise, the pulmonary vein carries oxygenated blood back to the heart. Year 7 learners may not need all circulatory details, but knowing that "artery" refers to direction of flow, not oxygen content, stops a stubborn misconception from forming.
正确的定义是，动脉将血液带离心脏，而静脉将血液送回心脏。大多数动脉确实输送含氧血，但也有重要的例外。肺动脉将缺氧血从心脏运送到肺部。同样地，肺静脉将含氧血带回心脏。七年级学生不一定需要所有循环系统的细节，但知道“动脉”指的是血流的方向而不是含氧量，可以防止形成一个顽固的误解。
12. Science Gives Fixed, Unchanging Truths | 科学给出固定不变的真理
The way early science is sometimes taught can give the impression that biology is a collection of facts to be memorised. Pupils may think that once a "fact" is in the textbook, it will never be updated. This affects how they approach new evidence.
早期科学的教学方式有时会给人一种印象，即生物学是一堆需要记忆的事实。学生可能认为，一旦某个“事实”写进了教科书，它就永远不会更新。这会影响他们对待新证据的方式。
Scientific knowledge is based on evidence and is open to change when new discoveries are made. Our understanding of cells, genetics, and ecosystems has evolved over centuries and continues to do so. In Year 7, students are encouraged to ask questions and understand that biology, like all sciences, is a process of continual testing and refinement. Embracing this mindset early helps learners become resilient and curious thinkers, rather than passive acceptors of information.
科学知识建立在证据之上，并在新发现出现时可能发生改变。我们对细胞、遗传和生态系统的理解在几个世纪中不断演变，如今仍在持续。在七年级，我们鼓励学生提出问题，并理解生物学像所有科学一样，是一个不断检验和完善的过程。尽早接受这种思维方式，有助于学生成为有韧性、充满好奇心的思考者，而不是信息的被动接受者。
Published by TutorHao | Biology Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图