IB WJEC Science: Environmental Science Key Points | IB WJEC 科学：环境科学考点精讲

📚 IB WJEC Science: Environmental Science Key Points | IB WJEC 科学：环境科学考点精讲

This article distils the essential concepts of environmental science as covered in IB and WJEC science curricula. It provides clear explanations of ecosystems, nutrient cycles, human impacts, and sustainability, helping you consolidate key knowledge for assessments. Each section presents a concise English explanation followed by its Chinese equivalent to support bilingual learning.

本文提炼了 IB 和 WJEC 科学课程中环境科学的核心概念，清晰地解释了生态系统、养分循环、人类影响与可持续发展等内容，帮助你巩固评估所需的关键知识。每个部分都先提供简明的英文解释，再给出对应的中文说明，以支持双语学习。

1. Ecosystems and Energy Flow | 生态系统与能量流动

An ecosystem consists of a community of living organisms interacting with each other and their non-living environment. Energy enters most ecosystems through sunlight, which is captured by producers via photosynthesis. This energy is transferred along food chains and webs, but only about 10% is passed from one trophic level to the next, with the rest lost as heat through respiration.

生态系统由生物群落及其与非生物环境的相互作用组成。能量大多通过阳光进入生态系统，被生产者通过光合作用固定。这些能量沿食物链和食物网传递，但大约只有 10% 从一个营养级传递到下一个营养级，其余部分通过呼吸作用以热量形式散失。

Producers, or autotrophs, convert inorganic carbon into organic compounds. Consumers, or heterotrophs, obtain energy by feeding on other organisms. Decomposers break down dead matter, recycling nutrients. The energy flow is unidirectional and ultimately exits the system as heat.

生产者（自养生物）将无机碳转化为有机化合物。消费者（异养生物）通过取食其他生物获取能量。分解者分解死体物质，循环养分。能量流动是单向的，最终以热量形式离开系统。

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2. Nutrient Cycles: Carbon and Nitrogen | 养分循环：碳循环与氮循环

Nutrients are continually recycled within ecosystems. The carbon cycle involves photosynthesis, respiration, decomposition, and combustion. Carbon dioxide is taken up by plants, incorporated into organic matter, and released back through respiration or burning. Oceans and fossil fuels act as major carbon reservoirs.

养分在生态系统中不断循环。碳循环包括光合作用、呼吸作用、分解和燃烧。二氧化碳被植物吸收，转化成有机物，并通过呼吸或燃烧重新释放。海洋和化石燃料是重要的碳库。

The nitrogen cycle is driven by microorganisms. Nitrogen fixation converts atmospheric N₂ into ammonium (NH₄⁺) by bacteria or lightning. Nitrification transforms ammonium into nitrites (NO₂⁻) and then nitrates (NO₃⁻), which plants can absorb. Denitrification returns nitrogen gas to the atmosphere.

氮循环由微生物驱动。固氮作用通过细菌或闪电将大气中的 N₂ 转化为铵（NH₄⁺）。硝化作用将铵依次转化为亚硝酸盐（NO₂⁻）和硝酸盐（NO₃⁻），供植物吸收。反硝化作用将氮气返回大气。

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3. Biodiversity and Its Importance | 生物多样性及其重要性

Biodiversity refers to the variety of life at all levels: genetic diversity within species, species diversity within communities, and ecosystem diversity across landscapes. High biodiversity enhances ecosystem resilience, productivity, and stability. It provides ecosystem services such as pollination, water purification, and climate regulation.

生物多样性指各个层次的生命多样性：物种内的遗传多样性、群落内的物种多样性以及景观尺度上的生态系统多样性。高生物多样性增强了生态系统的恢复力、生产力和稳定性，并提供授粉、净化水和气候调节等生态系统服务。

Human activities, including habitat destruction, overexploitation, pollution, and climate change, are accelerating biodiversity loss. Conservation strategies range from protecting key habitats to captive breeding and legislation. The IB and WJEC specifications often examine case studies of successful conservation efforts.

栖息地破坏、过度开发、污染和气候变化等人类活动正在加速生物多样性的丧失。保护策略包括保护关键栖息地、人工繁育和立法。IB 和 WJEC 的考纲常考查成功保护案例的研究。

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4. Population Dynamics and Carrying Capacity | 种群动态与环境容纳量

Populations change in size due to birth rate, death rate, immigration, and emigration. Exponential growth occurs under ideal conditions, but eventually limiting factors such as food, space, and disease cause growth to slow and level off at the carrying capacity (K) of the environment.

种群大小因出生率、死亡率、迁入和迁出而变化。在理想条件下出现指数增长，但食物、空间和疾病等限制因素最终会使增长减缓并稳定在环境容纳量（K）附近。

Population growth can be modeled using a logistic S-curve. Predator-prey interactions often show cyclical fluctuations. Human population growth has implications for resource use, waste production, and ecological footprint. Understanding these dynamics is essential for sustainable resource management.

种群增长可以用 S 型逻辑曲线建模。捕食者-猎物关系常呈现周期性波动。人口增长对资源使用、废物产生和生态足迹都有影响。理解这些动态对可持续资源管理至关重要。

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5. Pollution: Sources, Effects, and Control | 污染：来源、影响与控制

Pollution is the introduction of harmful materials into the environment. Air pollutants such as sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) cause acid rain, damaging ecosystems and buildings. Particulate matter affects human respiratory health. Greenhouse gases, including CO₂ and methane, drive global warming.

污染是有害物质进入环境。二氧化硫（SO₂）和氮氧化物（NOₓ）等空气污染物引起酸雨，损害生态系统和建筑物。颗粒物影响人体呼吸健康。二氧化碳和甲烷等温室气体导致全球变暖。

Water pollution from agricultural runoff introduces nitrates and phosphates, leading to eutrophication — an algal bloom that depletes oxygen and kills aquatic life. Plastics and microplastics pose long-term hazards. Control measures include catalytic converters, wastewater treatment, and legislation like the Clean Air Act.

农业径流造成的水污染引入硝酸盐和磷酸盐，导致富营养化——藻类大量繁殖，耗尽氧气，杀死水生生物。塑料和微塑料构成长期危害。控制措施包括催化转化器、污水处理和《清洁空气法案》等立法。

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6. Climate Change and Global Impacts | 气候变化与全球影响

The enhanced greenhouse effect is caused by increased atmospheric concentrations of greenhouse gases from human activities such as burning fossil fuels, deforestation, and agriculture. This traps more heat, raising global average temperatures. Evidence includes rising sea levels, shrinking ice sheets, and more frequent extreme weather events.

增强的温室效应由燃烧化石燃料、砍伐森林和农业等人类活动增加的大气温室气体浓度引起。这困住更多热量，提高了全球平均气温。证据包括海平面上升、冰盖缩小和更频繁的极端天气事件。

Climate change disrupts ecosystems, threatens food security, and causes habitat shifts. International agreements like the Paris Agreement aim to limit warming to well below 2°C. Mitigation strategies involve renewable energy, carbon capture, and reforestation; adaptation focuses on adjusting to inevitable changes.

气候变化扰乱生态系统，威胁粮食安全，并导致栖息地迁移。《巴黎协定》等国际协议旨在将升温限制在远低于 2°C。缓解策略包括采用可再生能源、碳捕集和再造林；适应则侧重于调整以应对不可避免的变化。

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7. Sustainability and Ecological Footprint | 可持续发展与生态足迹

Sustainability means meeting present needs without compromising the ability of future generations to meet their own needs. It balances three pillars: environmental integrity, social equity, and economic viability. The ecological footprint measures how much land and water area a human population requires to produce the resources it consumes and absorb its wastes.

可持续发展指既满足当代人需求，又不损害后代人满足自身需求的能力。它平衡三大支柱：环境完整性、社会公平和经济可行性。生态足迹衡量一个人口需要多少土地和水域面积来生产其所消费的资源并吸收其产生的废物。

If a population’s footprint exceeds biocapacity, it leads to overshoot, depleting natural capital. Reducing footprints involves using energy efficiently, conserving water, reducing waste, and adopting plant-rich diets. The concept of planetary boundaries defines a safe operating space for humanity.

如果一个种群的足迹超过生态承载力，就会导致超负荷，耗尽自然资本。减少足迹涉及高效利用能源、节约用水、减少浪费和采用植物为主的饮食。行星边界概念为人类界定了安全运行空间。

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8. Resource Management: Renewable and Non-renewable | 资源管理：可再生与不可再生资源

Non-renewable resources like fossil fuels and minerals exist in finite amounts and are consumed faster than they form. Renewable resources, such as solar, wind, and geothermal energy, can be replenished naturally. Sustainable resource management aims to match consumption rates with regeneration rates.

不可再生资源如化石燃料和矿物储量有限，消耗速度快于形成速度。太阳能、风能和地热能等可再生资源可以自然补充。可持续资源管理旨在使消耗速率与再生速率相匹配。

Energy security and environmental impacts drive the transition to renewables. Life-cycle assessment (LCA) evaluates a product’s environmental impact from cradle to grave, including raw material extraction, manufacturing, use, and disposal. This tool helps compare sustainability of materials and energy sources.

能源安全和环境影响推动向可再生能源转型。生命周期评估（LCA）从摇篮到坟墓评估产品对环境的影响，包括原材料提取、制造、使用和处置。这一工具有助于比较材料和能源的可持续性。

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9. Environmental Ethics and Policy | 环境伦理与政策

Environmental ethics examines the moral relationship between humans and the environment. Anthropocentrism values nature primarily for human benefit, while biocentrism recognizes intrinsic value in all living beings. Deep ecology advocates for radical restructuring of society to respect nature.

环境伦理探讨人类与环境之间的道德关系。人类中心主义主要从人类利益出发评价自然，而生物中心主义承认所有生命的内在价值。深层生态学主张彻底重构社会以尊重自然。

Governments and organizations use policies like environmental impact assessments (EIA), conservation laws, and international treaties to protect the environment. The precautionary principle states that if an action or policy has a suspected risk of causing harm, in the absence of scientific consensus, the burden of proof falls on those taking the action.

政府和组织利用环境影响评估（EIA）、保护法和国际条约等政策来保护环境。预防原则指出，如果某项行动或政策有造成危害的潜在风险，在缺乏科学共识的情况下，举证责任应由发起该行动的一方承担。

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10. Waste Management and Circular Economy | 废物管理与循环经济

Linear economies follow a ‘take-make-dispose’ model, leading to large amounts of waste. In contrast, a circular economy designs out waste, keeps materials in use, and regenerates natural systems. Strategies include reducing consumption, reusing products, recycling materials, and recovering energy from waste.

线性经济遵循“取用-制造-丢弃”模式，导致大量废物。相反，循环经济设计消除废物，保持材料使用，并再生自然系统。策略包括减少消耗、重复使用产品、回收利用材料以及从废物中回收能源。

Proper waste treatment, such as anaerobic digestion of organic waste or incineration with energy recovery, minimizes landfill use. Landfills produce methane, a potent greenhouse gas, and can leach toxic substances into groundwater. Legislation increasingly promotes extended producer responsibility, requiring manufacturers to manage end-of-life products.

适当的废物处理，如有机废物的厌氧消化或焚烧发电，可最大限度地减少填埋。填埋场产生强效温室气体甲烷，并可能渗滤有毒物质进入地下水。立法日益提倡生产者责任延伸，要求制造商管理寿命终期的产品。

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Published by TutorHao | Environmental Science Revision Series | aleveler.com

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