📚 IGCSE Science: Environmental Science Key Points | IGCSE 科学：环境科学 考点精讲
Environmental science is a vital part of the IGCSE Science syllabus, focusing on the relationships between living organisms and their surroundings. It covers essential topics such as ecosystems, pollution, resource management, and sustainability. Understanding these concepts not only prepares you for your exams but also equips you with the knowledge to address real-world environmental challenges. This article breaks down the key points you must master for the IGCSE Environmental Science section.
环境科学是 IGCSE 科学课程的重要组成部分，重点研究生物体与其周围环境之间的关系。它涵盖了生态系统、污染、资源管理和可持续发展等重要主题。理解这些概念不仅能为你的考试做好准备，还能让你具备应对现实环境挑战的知识。本文梳理了 IGCSE 环境科学部分你必须掌握的核心考点。
1. Ecosystems and Habitats | 生态系统与栖息地
An ecosystem is a natural unit consisting of all the living organisms (biotic factors) in a particular area interacting with the non-living (abiotic) components such as sunlight, water, and soil. A habitat is the specific place where an organism lives, providing food, shelter, and mates.
生态系统是一个自然单元，由特定区域内的所有生物（生物因素）与阳光、水和土壤等非生物（非生物因素）成分相互作用构成。栖息地是生物生存的具体地点，为其提供食物、庇护所和配偶。
Within an ecosystem, a population refers to all the individuals of a single species living in the same area, while a community is made up of all the populations of different species interacting together. The environment includes all the external factors that affect an organism.
在生态系统中，种群指的是生活在同一区域内的同一物种的所有个体，而群落则由相互作用的不同物种种群组成。环境包括影响生物体的一切外部因素。
Ecosystems can vary in size from a small pond to a vast rainforest. They are dynamic and can change due to natural events or human impacts. A stable ecosystem maintains a balance between its components, but disruptions can lead to population declines or habitat loss.
生态系统的规模可以小到一个小池塘，大到一片广阔的雨林。它们是动态的，会因自然事件或人类影响而发生变化。一个稳定的生态系统在其各组成部分之间保持平衡，但干扰可能导致种群数量下降或栖息地丧失。
2. Food Chains and Food Webs | 食物链和食物网
, like plants, make their own food via photosynthesis. Consumers eat other organisms: primary consumers eat producers, secondary consumers eat primary consumers, and so on.
食物链展示了能量从一个生物体到另一个生物体的线性传递，以生产者开始。例如：草 → 兔 → 狐狸。生产者（如植物）通过光合作用制造自己的食物。消费者以其他生物为食：初级消费者吃生产者，次级消费者吃初级消费者，以此类推。
In reality, feeding relationships are more complex, forming a food web. A food web is a network of interconnected food chains, showing that most organisms eat more than one type of food. This complexity helps stabilize an ecosystem because if one food source declines, predators can switch to alternative prey.
现实中，摄食关系更为复杂，形成了食物网。食物网是由相互连接的食物链组成的网络，表明大多数生物不止吃一种食物。这种复杂性有助于维持生态系统的稳定，因为如果一个食物来源减少，捕食者可以转而捕食其他猎物。
Energy is lost at each trophic level, mainly as heat from respiration. Typically, only about 10% of the energy is passed on to the next level. This limits the length of food chains to usually no more than four or five levels. Decomposers, such as bacteria and fungi, break down dead organisms and recycle nutrients back into the soil.
能量在每个营养级都会损失，主要以呼吸作用产生的热量形式散失。通常只有大约10%的能量传递到下一营养级。这限制了食物链的长度，通常不超过四到五个层级。分解者（如细菌和真菌）分解死亡的生物体，将养分循环回土壤。
3. Biodiversity | 生物多样性
Biodiversity refers to the variety of life on Earth, including species diversity, genetic diversity within species, and ecosystem diversity. High biodiversity is crucial for ecosystem resilience, allowing ecosystems to recover from disturbances and maintain functions like pollination, water purification, and climate regulation.
生物多样性指地球上生命的多样性，包括物种多样性、物种内的遗传多样性以及生态系统多样性。高生物多样性对生态系统的恢复力至关重要，使其能够从干扰中恢复，并维持传粉、水净化和气候调节等功能。
Many factors threaten biodiversity, including habitat destruction, overexploitation, pollution, and the introduction of invasive species. Climate change is also becoming a major driver. Loss of biodiversity can lead to the collapse of food webs and the loss of potential sources of medicine and other resources.
许多因素威胁着生物多样性，包括栖息地破坏、过度开发、污染和入侵物种的引入。气候变化也正成为一个主要驱动因素。生物多样性的丧失可能导致食物网崩溃，以及潜在药物和其他资源来源的丧失。
Conserving biodiversity involves protecting natural habitats, creating nature reserves, captive breeding programs, and seed banks. International agreements like the Convention on Biological Diversity aim to reduce biodiversity loss globally.
保护生物多样性涉及保护自然栖息地、建立自然保护区、实施圈养繁殖计划和建立种子库。像《生物多样性公约》这样的国际协议旨在减少全球范围内的生物多样性丧失。
4. Deforestation | 森林砍伐
Deforestation is the large-scale removal of forests, often to clear land for agriculture, urban development, or timber extraction. It has severe environmental consequences, including habitat destruction, loss of biodiversity, and disruption of the water cycle.
森林砍伐是指大规模砍伐森林，通常是为了开垦农业用地、城市建设或获取木材。这会带来严重的环境后果，包括栖息地破坏、生物多样性丧失以及水循环的扰乱。
Trees play a vital role in absorbing carbon dioxide and producing oxygen through photosynthesis. Deforestation reduces this carbon sink, contributing to higher atmospheric CO₂ levels and global warming. It can also lead to soil erosion, as tree roots that bind the soil are removed, increasing the risk of landslides and desertification.
树木在通过光合作用吸收二氧化碳并产生氧气方面起着关键作用。森林砍伐减少了这种碳汇，导致大气中二氧化碳含量升高和全球变暖。它还可能导致水土流失，因为起固土作用的树根被移除，增加了滑坡和荒漠化的风险。
Leaching of nutrients occurs when heavy rain washes minerals out of the soil after deforestation. The land quickly becomes infertile. Sustainable forestry practices, such as selective logging and replanting, can help mitigate these effects.
森林砍伐后，大雨会将土壤中的矿物质冲刷掉，发生养分淋溶。土地很快就会变得贫瘠。可持续的林业做法，如选择性采伐和重新种植，有助于减轻这些影响。
5. Air Pollution | 空气污染
Air pollution is caused by the release of harmful substances into the atmosphere. Common pollutants include carbon monoxide (CO) from incomplete combustion, sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) from burning fossil fuels, and particulate matter (PM) from vehicles and industry.
空气污染是由有害物质排放到大气中所引起的。常见的污染物包括不完全燃烧产生的一氧化碳 (CO)、燃烧化石燃料产生的二氧化硫 (SO₂) 和氮氧化物 (NOₓ)，以及车辆和工业产生的颗粒物 (PM)。
Carbon monoxide binds with hemoglobin in red blood cells more readily than oxygen, reducing the blood’s oxygen-carrying capacity and causing fatigue or even death. Sulfur dioxide and nitrogen oxides contribute to acid rain and respiratory problems. Particulate matter can penetrate deep into the lungs, causing asthma and cardiovascular diseases.
一氧化碳比氧气更容易与红细胞中的血红蛋白结合，降低了血液的携氧能力，导致疲劳甚至死亡。二氧化硫和氮氧化物会导致酸雨和呼吸系统疾病。颗粒物可深入肺部，引发哮喘和心血管疾病。
To reduce air pollution, we can use catalytic converters in cars to convert harmful gases into less harmful ones, switch to renewable energy sources, and enforce stricter emission standards. Planting trees also helps filter pollutants from the air.
为了减少空气污染，我们可以在汽车上安装催化转换器，将有害气体转化为危害较小的气体，转向使用可再生能源，并执行更严格的排放标准。植树也有助于过滤空气中的污染物。
6. Water Pollution and Eutrophication | 水污染与富营养化
Water pollution occurs when harmful substances, such as sewage, agricultural runoff, and industrial waste, contaminate water bodies. Sewage contains organic matter and pathogens, while fertilizers and detergents contain nitrates and phosphates that can cause eutrophication.
水污染是指污水、农业径流和工业废水等有害物质污染水体的情况。污水含有有机物和病原体，而化肥和洗涤剂中含有可导致富营养化的硝酸盐和磷酸盐。
Eutrophication is the process where excess nutrients enter a water body, leading to rapid algae growth (algal bloom). The algae block sunlight from reaching underwater plants, causing them to die. Decomposers then feed on the dead plants, consuming dissolved oxygen in the water.
富营养化是指过量的营养物质进入水体，导致藻类迅速生长（藻华）。藻类阻挡阳光照射水下植物，导致它们死亡。分解者随后分解死去的植物，消耗水中的溶解氧。
This oxygen depletion, or deoxygenation, can create dead zones where fish and other aquatic life cannot survive. Reducing the use of fertilizers, treating sewage before discharge, and using phosphate-free detergents can help prevent eutrophication.
这种氧气耗竭（或称脱氧）会产生死亡区域，鱼类和其他水生生物无法生存。减少化肥使用、在排放前处理污水以及使用无磷洗涤剂，有助于防止富营养化。
7. Acid Rain | 酸雨
Acid rain forms when sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) are released into the atmosphere from burning fossil fuels. They react with water, oxygen, and other chemicals to form sulfuric acid and nitric acid. These acids fall as wet deposition (rain, snow) or dry deposition (particles).
酸雨是由燃烧化石燃料释放的二氧化硫 (SO₂) 和氮氧化物 (NOₓ) 在大气中形成的。它们与水、氧气和其他化学物质反应，生成硫酸和硝酸。这些酸以湿沉降（雨、雪）或干沉降（颗粒物）的形式降落。
SO₂ + H₂O → H₂SO₃ (sulfurous acid)
SO₂ + H₂O → H₂SO₃（亚硫酸）
Acid rain lowers the pH of soil and freshwater lakes, harming plants and aquatic life. It damages buildings and statues made of limestone or marble, as the calcium carbonate reacts with the acid. It also leaches toxic metals like aluminium from the soil, which can poison fish.
酸雨降低了土壤和淡水湖泊的pH值，危害植物和水生生物。它会损坏石灰石或大理石建造的建筑物和雕像，因为碳酸钙会与酸发生反应。它还会将铝等有毒金属从土壤中淋溶出来，毒害鱼类。
Reducing SO₂ and NOₓ emissions is the main solution. This can be achieved by using low-sulfur fuels, installing scrubbers in power station chimneys to remove sulfur dioxide, and using catalytic converters in vehicles. International agreements have helped decrease acid rain in many regions.
主要解决方案是减少二氧化硫和氮氧化物的排放。这可以通过使用低硫燃料、在发电站烟囱中安装洗涤器来去除二氧化硫，以及在车辆上使用催化转换器来实现。国际协定已帮助许多地区减少了酸雨。
8. Global Warming and the Greenhouse Effect | 全球变暖与温室效应
The greenhouse effect is a natural process where certain gases in the atmosphere trap heat from the Sun, keeping Earth warm enough for life. However, human activities have increased the concentration of these greenhouse gases, enhancing the effect and leading to global warming.
温室效应是一个自然过程，大气中的某些气体捕获太阳的热量，使地球保持足够温暖以维持生命。然而，人类活动增加了这些温室气体的浓度，增强了这一效应，导致全球变暖。
The main greenhouse gases are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and water vapour. CO₂ is released by burning fossil fuels and deforestation. Methane comes from cattle, rice paddies, and landfills. Nitrous oxide is emitted from agricultural fertilizers.
主要的温室气体有二氧化碳 (CO₂)、甲烷 (CH₄)、一氧化二氮 (N₂O) 和水蒸气。二氧化碳通过燃烧化石燃料和森林砍伐释放。甲烷来自牛、稻田和垃圾填埋场。一氧化二氮由农用化肥排放。
Consequences of global warming include rising sea levels due to melting ice caps, more frequent and severe weather events, changes in ecosystems, and loss of biodiversity. Coral bleaching occurs when higher water temperatures cause corals to expel the algae living in their tissues.
全球变暖的后果包括冰盖融化导致海平面上升、更频繁和更严重的极端天气事件、生态系统变化以及生物多样性的丧失。水温升高会导致珊瑚排出生活在其组织内的藻类，从而发生珊瑚白化。
Mitigation strategies include switching to renewable energy, improving energy efficiency, reforestation, and adopting sustainable agricultural practices. Carbon capture and storage technology is also being developed to remove CO₂ from the atmosphere.
缓解策略包括转向可再生能源、提高能源效率、植树造林以及采用可持续农业做法。碳捕获和封存技术也在开发中，以去除大气中的二氧化碳。
9. Renewable and Non-renewable Resources | 可再生与不可再生资源
Natural resources can be classified as renewable or non-renewable. Renewable resources, such as solar, wind, hydro, and biomass, can be replenished at a rate comparable to their consumption. Non-renewable resources, like fossil fuels (coal, oil, natural gas) and nuclear fuels, exist in finite amounts and take millions of years to form.
自然资源可分为可再生资源和不可再生资源。可再生资源，如太阳能、风能、水力和生物质能，能够以与消耗速度相当的速度得到补充。不可再生资源，如化石燃料（煤、石油、天然气）和核燃料，储量有限，需要数百万年才能形成。
| Feature | Renewable | Non-renewable |
|---|---|---|
| Availability | Virtually unlimited | Limited, will run out |
| Pollution | Generally low | High CO₂ and SO₂ emissions |
| Examples | Solar, wind, tidal, geothermal | Coal, oil, natural gas, uranium |
表：可再生资源与不可再生资源对比
Burning fossil fuels is the largest contributor to greenhouse gas emissions. Switching to renewables reduces our carbon footprint and helps combat climate change. However, renewable energy sources often require initial high investment and are sometimes weather-dependent, so energy storage solutions are needed.
燃烧化石燃料是温室气体排放的最大来源。转向可再生能源可减少我们的碳足迹，有助于应对气候变化。然而，可再生能源通常需要较高的初始投资，并且有时依赖天气，因此需要储能解决方案。
10. Sustainable Development | 可持续发展
Sustainable development means meeting the needs of the present without compromising the ability of future generations to meet their own needs. It balances economic growth, social equity, and environmental protection. It encourages the use of resources in ways that do not deplete them or harm the environment permanently.
可持续发展是指在不损害后代满足其自身需求的能力的前提下，满足当代人的需求。它平衡了经济增长、社会公平和环境保护。它鼓励以不会耗尽资源或永久损害环境的方式使用资源。
Examples of sustainable practices include using fish quotas to prevent overfishing, practicing crop rotation and organic farming, and constructing energy-efficient buildings. In forestry, replanting trees after logging ensures that wood remains available for future generations.
可持续做法的例子包括使用渔业配额防止过度捕捞、实行轮作和有机农业，以及建造节能建筑。在林业方面，采伐后重新植树确保后代仍有木材可用。
Sustainability also involves reducing waste and promoting recycling. The concept of a circular economy, where products are reused and recycled rather than thrown away, is gaining momentum. Education and legislation are key to encouraging sustainable behaviour.
可持续发展还涉及减少废物和促进回收利用。循环经济的概念（即产品被重复使用和回收而不是丢弃）正日益受到重视。教育和立法是鼓励可持续行为的关键。
11. Conservation and Recycling | 保护与循环利用
Conservation is the protection and management of natural resources to prevent their exploitation, destruction, or degradation. This includes preserving species, habitats, and ecosystems. Recycling involves converting waste materials into new products to reduce the consumption of raw materials and energy.
保护是指对自然资源进行保护和管理，以防止其被开发、破坏或退化。这包括保护物种、栖息地和生态系统。回收利用是指将废旧材料转化为新产品，以减少原材料和能源的消耗。
Recycling metals like aluminium saves up to 95% of the energy needed to extract new aluminium from its ore. Recycling paper reduces deforestation and water usage. Glass and plastics can also be recycled, although some plastics are harder to recycle effectively.
回收铝等金属可节省高达95%从矿石中提取新铝所需的能源。回收纸张可以减少森林砍伐和用水量。玻璃和塑料也可以回收，尽管有些塑料难以有效回收。
Challenges include contamination of recyclable materials and the economics of recycling when virgin materials are cheaper. Nevertheless, effective recycling programs reduce landfill waste, conserve resources, and decrease pollution. Legislation, such as deposit-return schemes for bottles, can increase recycling rates.
挑战包括可回收材料的污染以及当原生材料更便宜时回收的经济性问题。尽管如此，有效的回收计划减少了垃圾填埋场的废物，节约了资源，并减少了污染。立法，如瓶子押金退还计划，可以提高回收率。
12. Nutrient Cycles: Carbon and Nitrogen | 营养循环：碳循环与氮循环
Nutrients are constantly recycled within ecosystems through biogeochemical cycles. Two critical cycles are the carbon cycle and the nitrogen cycle. Both are essential for life and are heavily influenced by human activities.
营养物质通过生物地球化学循环在生态系统中不断再循环。其中两个至关重要的循环是碳循环和氮循环。两者对生命都不可或缺，并深受人类活动的影响。
In the carbon cycle, carbon moves between the atmosphere, oceans, living organisms, and the earth. Photosynthesis removes CO₂ from the air to form glucose. Respiration, combustion, and decomposition return CO₂ to the atmosphere. Over millions of years, carbon can be stored as fossil fuels or sedimentary rocks.
在碳循环中，碳在大气、海洋、生物体和地球之间移动。光合作用从空气中吸收二氧化碳生成葡萄糖。呼吸作用、燃烧和分解将二氧化碳释放回大气。在数百万年的时间里，碳可以以化石燃料或沉积岩的形式储存。
Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
光合作用：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
The nitrogen cycle involves the conversion of nitrogen gas (N₂) into forms usable by plants. Nitrogen fixation by bacteria in the soil or root nodules of legumes converts N₂ into ammonia (NH₃). Nitrification then converts ammonia to nitrites (NO₂⁻) and then to nitrates (NO₃⁻). Plants absorb nitrates to make proteins. Denitrification returns nitrogen gas to the atmosphere.
氮循环涉及将氮气 (N₂) 转化为植物可利用的形式。固氮作用由土壤中或豆科植物根瘤中的细菌完成，将 N₂ 转化为氨 (NH₃)。随后硝化作用将氨转化为亚硝酸盐 (NO₂⁻)，再转化为硝酸盐 (NO₃⁻)。植物吸收硝酸盐制造蛋白质。反硝化作用将氮气返回大气。
Excessive use of nitrogen-based fertilizers can disrupt the nitrogen cycle, leading to eutrophication in water bodies and soil acidification. The burning of fossil fuels also releases nitrogen oxides, contributing to both acid rain and the greenhouse effect.
过量使用氮肥会扰乱氮循环，导致水体富营养化和土壤酸化。燃烧化石燃料还会释放氮氧化物，导致酸雨和温室效应。
Published by TutorHao | Science 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