GCSE WJEC Biology: Mastering Ecology | GCSE WJEC 生物：生态学考点精讲

📚 GCSE WJEC Biology: Mastering Ecology | GCSE WJEC 生物：生态学考点精讲

Ecology is the study of how organisms interact with each other and their environment. For your WJEC GCSE Biology exam, you need to understand key concepts such as ecosystems, food chains, nutrient cycles, and the impact of human activities. This revision guide breaks down every essential topic, with clear bilingual explanations to help you succeed.

生态学研究生物如何彼此以及与环境相互作用。对于 WJEC GCSE 生物考试，你需要掌握生态系统、食物链、物质循环以及人类活动的影响等核心概念。本考点精讲用清晰的中英双语解释逐一拆分每个重要主题，帮助你顺利备考。

1. What Is an Ecosystem? | 什么是生态系统？

An ecosystem is made up of all the organisms living in a particular area (the community) and the non-living (abiotic) parts of their environment, such as soil, water, and climate. A habitat is the place where an organism lives, while a population is all the individuals of one species in that habitat.

生态系统由生活在特定区域的所有生物（群落）及其环境中的非生物部分（如土壤、水和气候）组成。栖息地是生物居住的地方，而种群是同一物种在该栖息地中的所有个体。

Within an ecosystem, organisms depend on each other for food, shelter, and reproduction. A community includes many populations of different species interacting. The size of each population can change due to factors like competition, predation, and disease.

在生态系统中，生物彼此依赖以获取食物、庇护和繁殖。群落包含许多不同物种种群的相互作用。每个种群的大小会因竞争、捕食和疾病等因素而变化。

2. Abiotic Factors | 非生物因素

Abiotic factors are the non-living physical and chemical conditions that affect organisms. Examples include temperature, light intensity, moisture levels, soil pH, and the availability of oxygen or carbon dioxide. These factors determine which species can survive in a habitat.

非生物因素是影响生物的非生命物理和化学条件。例子包括温度、光照强度、湿度、土壤 pH 值以及氧气或二氧化碳的可用性。这些因素决定了哪些物种能在某个栖息地生存。

For instance, aquatic plants need plenty of light for photosynthesis, so they are usually found near the surface of water. Earthworms need moist soil because their skin must stay damp to allow gas exchange. If an abiotic factor changes, populations may increase, decrease, or even disappear.

例如，水生植物需要充足光线进行光合作用，因此通常生活在水面附近。蚯蚓需要潮湿的土壤，因为它们的皮肤必须保持湿润才能进行气体交换。如果非生物因素改变，种群可能增加、减少甚至消失。

3. Biotic Factors | 生物因素

Biotic factors are the living components of an ecosystem that influence organisms. They include competition, predation, parasitism, and mutualism. These interactions can be within the same species (intraspecific) or between different species (interspecific).

生物因素是生态系统中影响生物的生命组成部分，包括竞争、捕食、寄生和互利共生。这些相互作用可以是同一物种内部的（种内）或不同物种之间的（种间）。

Competition happens when organisms need the same limited resources, such as food, water, light, or space. Predation keeps prey populations in check. In mutualism, both species benefit, like bees pollinating flowers while obtaining nectar.

当生物需要相同的有限资源（如食物、水、光或空间）时，就会发生竞争。捕食可以控制猎物种群的数量。在互利共生中，双方都受益，例如蜜蜂为花朵授粉同时获取花蜜。

4. Food Chains and Food Webs | 食物链与食物网

A food chain shows the flow of energy from one organism to another. It always starts with a producer (a plant or alga that photosynthesises), followed by a series of consumers. Decomposers break down dead material and return nutrients to the soil, but they are often not included in simple food chain diagrams.

食物链显示了能量从一个生物流向另一个生物的过程。它总是以生产者（能进行光合作用的植物或藻类）开始，随后是一系列消费者。分解者分解死物并将养分归还土壤，但它们通常不包含在简单的食物链图中。

Most organisms eat more than one type of food, so food chains are linked to form a food web. A food web gives a more realistic picture of feeding relationships in an ecosystem. Arrows always point in the direction of energy flow, from eaten to eater.

大多数生物不止吃一种食物，因此多条食物链相连形成食物网。食物网更真实地反映了生态系统中的摄食关系。箭头始终指向能量流动的方向，即从被吃者指向吃者。

5. Energy Flow and Ecological Pyramids | 能量流动与生态金字塔

At each trophic level (feeding level) in a food chain, energy is lost. Only about 10% of the energy is passed on to the next level; the rest is lost through movement, heat, respiration, and uneaten parts. This limits the length of food chains.

在食物链的每个营养级中，能量都会损失。只有约 10% 的能量传递到下一级；其余的能量通过运动、热量、呼吸作用以及未被食用的部分散失。这限制了食物链的长度。

Ecologists use pyramids to represent trophic levels. A pyramid of numbers shows the count of organisms at each level; a pyramid of biomass shows their total mass; and a pyramid of energy shows the energy stored, which is always pyramid-shaped because energy decreases up the chain.

生态学家用金字塔来表示营养级。数量金字塔显示每个营养级的个体数量；生物量金字塔显示总质量；能量金字塔显示储存的能量，由于能量沿食物链递减，它始终呈金字塔形。

Energy efficiency = (Energy in trophic level / Energy in previous level) × 100%

能量效率 = (该营养级能量 / 上一营养级能量) × 100%

6. The Carbon Cycle | 碳循环

Carbon is essential for life and circulates between the atmosphere, organisms, and the soil. Key processes include photosynthesis (carbon dioxide removed from air), respiration (carbon dioxide returned), feeding (carbon moves along food chains), decomposition (release by microbes), and combustion (burning fossil fuels).

碳对生命至关重要，在大气、生物体和土壤之间循环。关键过程包括光合作用（从空气中吸收二氧化碳）、呼吸作用（释放二氧化碳）、摄食（碳沿食物链传递）、分解（微生物释放）和燃烧（燃烧化石燃料）。

Human activities such as deforestation and burning fossil fuels are increasing atmospheric carbon dioxide levels, contributing to the enhanced greenhouse effect and global warming. Oceans act as carbon sinks, absorbing large amounts of CO₂, but this leads to ocean acidification.

砍伐森林和燃烧化石燃料等人类活动正在增加大气中的二氧化碳含量，加剧温室效应和全球变暖。海洋作为碳汇吸收大量 CO₂，但这会导致海洋酸化。

7. The Nitrogen Cycle | 氮循环

Plants and animals need nitrogen to make proteins and DNA, but they cannot use atmospheric nitrogen (N₂) directly. The nitrogen cycle involves nitrogen fixation (conversion to ammonia by bacteria or lightning), nitrification (ammonia to nitrites then nitrates), assimilation by plants, and denitrification back to N₂.

植物和动物需要氮来制造蛋白质和 DNA，但它们无法直接利用大气中的氮气 (N₂)。氮循环包括固氮（细菌或闪电将氮气转化为氨）、硝化作用（氨转为亚硝酸盐再转为硝酸盐）、植物同化吸收和反硝化作用（重新变回 N₂）。

Key bacteria include Rhizobium (found in legume root nodules) that fix nitrogen, Nitrosomonas that convert ammonia to nitrite, Nitrobacter that convert nitrite to nitrate, and Pseudomonas that carry out denitrification in waterlogged soils.

关键的细菌有：根瘤菌（生活在豆科植物根瘤中）固氮、亚硝化单胞菌将氨转化为亚硝酸盐、硝化杆菌将亚硝酸盐转化为硝酸盐，以及假单胞菌在淹水土壤中进行反硝化作用。

8. Population Growth and Carrying Capacity | 种群增长与承载力

A population can grow exponentially under ideal conditions (unlimited resources). In reality, populations follow a logistic growth curve, where growth slows as resources become limited, eventually reaching the carrying capacity – the maximum population size the environment can sustain.

在理想条件下（资源无限），种群可以呈指数增长。在现实中，种群遵循逻辑斯谛生长曲线：随着资源变得有限，增长速度减慢，最终达到承载力——环境能维持的最大种群规模。

Factors that limit population size include food availability, predation, disease, and accumulation of waste. These are called limiting factors. WJEC exams often ask you to interpret graphs showing population fluctuations of predator and prey.

限制种群大小的因素包括食物可得性、捕食、疾病和废物积累，这些称为限制因子。WJEC 考试常要求你解读显示捕食者与猎物种群波动的图形。

9. Sampling Techniques | 取样技术

Ecologists cannot count every organism in an area, so they use sampling techniques to estimate population sizes. Common methods include quadrats (square frames placed randomly to count organisms or estimate percentage cover) and transects (lines along which samples are taken at regular intervals).

生态学家无法逐个统计区域内的所有生物，因此他们使用取样技术来估算种群大小。常见方法包括样方（随机放置的方框，用于计数生物或估算覆盖率）和样线（沿一条线等间隔取样）。

For mobile animals, the mark-release-recapture method is used. Animals are captured, marked in a harmless way, released, and later recaptured. The population size is estimated using the Lincoln index:

对于移动的动物，使用标记-释放-重捕法。捕获动物，用无害方式标记，释放，再重新捕获。种群大小通过林肯指数估算：

Population = (Number in 1st sample × Number in 2nd sample) / Number of marked individuals recaptured

种群大小 = (第一次捕获数 × 第二次捕获数) / 重捕中标记的个体数

10. Human Impacts on Ecosystems | 人类对生态系统的影响

Human activities have significant effects on ecosystems. Air pollution, especially sulfur dioxide and nitrogen oxides, leads to acid rain, which damages plants, soils, and aquatic life. Eutrophication occurs when fertilisers run off into water, causing excessive algal growth that depletes oxygen and kills fish.

人类活动对生态系统有显著影响。空气污染，尤其是二氧化硫和氮氧化物，会导致酸雨，损害植物、土壤和水生生物。当肥料流入水体时，会发生富营养化，导致藻类过度生长，消耗氧气并使鱼类死亡。

Deforestation reduces biodiversity, destroys habitats, and disrupts the carbon, nitrogen, and water cycles. Burning forests releases carbon dioxide. In addition, plastic pollution harms wildlife and enters food chains, while climate change alters species distributions.

砍伐森林减少生物多样性，破坏栖息地，并扰乱碳、氮和水循环。焚烧森林释放二氧化碳。此外，塑料污染危害野生动物并进入食物链，气候变化改变物种分布。

11. Biodiversity and Conservation | 生物多样性与保护

Biodiversity is the variety of life on Earth, including species diversity, genetic diversity within species, and ecosystem diversity. High biodiversity makes ecosystems more stable and resilient to changes. It also provides us with food, medicines, and ecosystem services like pollination.

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。高生物多样性使生态系统更稳定、更能适应变化。它还为我们提供食物、药物和授粉等生态系统服务。

Conservation methods include setting up protected areas (nature reserves, national parks), captive breeding programmes, seed banks, and laws against poaching and deforestation. Sustainable practices like replanting trees and using renewable energy help maintain biodiversity.

保护方法包括建立保护区（自然保护区、国家公园）、圈养繁殖计划、种子库，以及禁止偷猎和砍伐森林的法律。可持续实践，如重新植树和使用可再生能源，有助于维持生物多样性。

12. Bioaccumulation and Biomagnification | 生物累积与生物放大

Some pollutants, such as pesticides like DDT, are not easily broken down in the environment. Bioaccumulation is the build-up of these chemicals in the body of an organism over time. Because they are fat-soluble, they accumulate in fatty tissues.

某些污染物，如 DDT 等杀虫剂，在环境中不容易分解。生物累积是指这些化学物质随时间在生物体内积累。由于它们是脂溶性的，会在脂肪组织中积累。

Biomagnification occurs when the concentration of the pollutant increases as it moves up the food chain. Top predators can have dangerously high levels, leading to health problems such as reproductive failure. This is a key concept in WJEC ecology questions.

当污染物沿食物链向上传递时，其浓度不断上升，这称为生物放大。顶级捕食者体内的污染物浓度可能极高，导致繁殖失败等健康问题。这是 WJEC 生态学题目中的一个重要概念。

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GCSE WJEC Biology: Mastering Ecology | GCSE WJEC 生物：生态学 考点精讲