Core Knowledge Overview for Year 7 Cambridge Biology | 核心知识点梳理

📚 Core Knowledge Overview for Year 7 Cambridge Biology | 核心知识点梳理

Understanding the fundamentals of biology at Year 7 level sets the stage for all future scientific study. This guide covers the essential topics in the Cambridge Lower Secondary Biology curriculum, from the characteristics of life to ecological relationships.

掌握七年级生物学的基础知识，为未来的科学学习打下坚实的基础。本指南涵盖了剑桥初中生物课程中的所有核心主题，从生命的基本特征到生态关系，帮助你全面梳理。

1. Characteristics of Living Things | 生物的特征

Biologists use seven life processes to define a living organism. The mnemonic ‘MRS GREN’ helps remember them: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.

生物学家用七个生命过程来定义生物体。我们可以用首字母口诀“MRS GREN”来记忆：运动（Movement）、呼吸（Respiration）、感应（Sensitivity）、生长（Growth）、繁殖（Reproduction）、排泄（Excretion）和营养（Nutrition）。

Life Process	English Explanation	中文解释
Movement	All living things move. Animals run, fly or swim; plants turn towards light.	所有生物都会运动。动物能跑、能飞或游泳；植物会向光生长。
Respiration	A chemical process in cells that releases energy from food, usually using oxygen.	细胞内释放食物中能量的化学过程，通常需要氧气。
Sensitivity	Responding to changes in the environment (stimuli). For example, pupils shrink in bright light.	对环境变化（刺激）作出反应。例如，强光下瞳孔会缩小。
Growth	A permanent increase in size or number of cells. All organisms grow and develop.	大小或细胞数量的永久性增加。所有生物都会生长和发育。
Reproduction	Producing offspring, either sexually (two parents) or asexually (one parent).	产生后代，可以是有性生殖（双亲）或无性生殖（单亲）。
Excretion	Removal of toxic metabolic waste, such as carbon dioxide and urine.	排除代谢产生的有毒废物，如二氧化碳和尿液。
Nutrition	Taking in materials for energy, growth and repair. Plants make their own food; animals eat other organisms.	摄取物质以获得能量、生长和修复。植物自己制造食物；动物摄食其他生物。

A car may move and release gases, but it does not grow or reproduce. Therefore, it is non-living. Something is either alive, dead, or has never been alive.

汽车可能移动并释放气体，但它不生长也不繁殖，因此是非生物。一个物体要么是活的，要么是死的，要么从未有过生命。

2. Cells – The Building Blocks of Life | 细胞——生命的基石

All organisms are made of cells. Animal cells have a cell membrane, cytoplasm, and a nucleus. Plant cells have the same three parts, plus a rigid cell wall, a large sap vacuole, and chloroplasts for photosynthesis.

所有生物都由细胞构成。动物细胞有细胞膜、细胞质和细胞核。植物细胞除了这三部分外，还有坚硬的细胞壁、一个大液泡和进行光合作用的叶绿体。

Although the human eye cannot see them, cells can be observed using a light microscope. Students often prepare onion epidermis or cheek cell slides by adding a drop of iodine or methylene blue stain.

虽然肉眼无法看到细胞，但可以用光学显微镜观察。学生们常制备洋葱表皮或口腔上皮细胞装片，并滴加碘液或亚甲蓝染色。

Some organisms, like bacteria, are unicellular, while animals and plants are multicellular. Different cells are specialised to perform distinct functions, such as red blood cells carrying oxygen.

一些生物，如细菌，是单细胞的，而动植物是多细胞的。不同的细胞特化以执行专门的功能，例如红细胞运输氧气。

3. Levels of Organisation | 组织的层次

In multicellular organisms, cells are organised into layers of increasing complexity: cells → tissues → organs → organ systems → organism.

在多细胞生物中，细胞组成了复杂程度递增的层次：细胞（cells）→ 组织（tissues）→ 器官（organs）→ 器官系统（organ systems）→ 个体（organism）。

A tissue is a group of similar cells working together, such as muscle tissue. An organ is made of different tissues working together, like the heart or a leaf. An organ system consists of a group of organs that perform a major function, e.g., the digestive system.

组织是一群相似细胞协同工作，例如肌肉组织。器官由不同的组织共同构成，如心脏或叶片。器官系统由一组执行主要功能的器官组成，例如消化系统。

Understanding this hierarchy helps explain how the human body carries out complex tasks: from individual muscle cells contracting to the whole skeletal system enabling movement.

理解这一层级有助于解释人体如何完成复杂任务：从单个肌肉细胞的收缩到整个骨骼系统实现运动。

4. Classification of Living Organisms | 生物的分类

Scientists sort millions of species into groups based on shared features. The largest groups are called kingdoms. The five-kingdom system is widely used: Animals, Plants, Fungi, Protoctists, and Prokaryotes.

科学家根据共同特征将数百万物种划分为不同的类群。最大的类群称为“界”。广泛使用的五界系统包括：动物界、植物界、真菌界、原生生物界和原核生物界。

Kingdom	Key Features	主要特征
Animals	Multicellular, no cell walls, heterotrophic (eat other organisms), usually can move.	多细胞，无细胞壁，异养（吃其他生物），通常能运动。
Plants	Multicellular, have cellulose cell walls, autotrophic (photosynthesis), contain chlorophyll.	多细胞，有纤维素细胞壁，自养（光合作用），含有叶绿素。
Fungi	Usually multicellular (except yeast), cell walls made of chitin, feed by saprophytic decomposition.	通常多细胞（酵母除外），细胞壁由几丁质构成，通过腐生分解获取营养。
Protoctists	Mostly unicellular eukaryotes, e.g., Amoeba, algae. Some are photosynthetic.	多为单细胞真核生物，如变形虫、藻类。有些能进行光合作用。
Prokaryotes	Unicellular, no true nucleus (DNA free in cytoplasm), e.g., bacteria.	单细胞，没有真正的细胞核（DNA游离在细胞质中），如细菌。

Within each kingdom, organisms are further divided into smaller groups: phylum, class, order, family, genus, and species. The binomial naming system gives every species a two-part Latin name, e.g., Homo sapiens.

在每一个界内，生物进一步被分为门、纲、目、科、属、种。双名法赋予每个物种一个由两部分拉丁文组成的学名，例如 Homo sapiens（智人）。

5. Plant Structure and Photosynthesis | 植物结构与光合作用

The main organs of a flowering plant are roots, stems, leaves and flowers. The leaf is the primary site of photosynthesis – the process that converts light energy into chemical energy stored in glucose.

开花植物的主要器官是根、茎、叶和花。叶片是光合作用的主要场所——光合作用将光能转化为储存在葡萄糖中的化学能。

Word equation: carbon dioxide + water → glucose + oxygen

文字方程式：二氧化碳 + 水 → 葡萄糖 + 氧气

Symbol equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

化学方程式：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

The leaf is adapted for photosynthesis: it is broad and flat to absorb light; it has many chloroplasts in the palisade mesophyll; stomata allow gas exchange; and veins bring water.

叶片适应光合作用：它宽大而扁平以便吸收光线；栅栏组织中含有大量叶绿体；气孔允许气体交换；叶脉输送水分。

Photosynthesis is affected by light intensity, carbon dioxide concentration, temperature, and water. These factors can act as limiting factors, slowing the rate down.

光合作用受光照强度、二氧化碳浓度、温度和水的影响。这些因素可能成为限制因子，降低反应速率。

6. Transport in Plants | 植物体内的运输

Plants have two specialised transport tissues: xylem and phloem. Xylem vessels carry water and dissolved minerals from the roots up to the leaves in a one-way flow. Phloem tubes transport sugars (mainly sucrose) from the leaves to the rest of the plant, in both directions.

植物有两种特化的输导组织：木质部和韧皮部。木质部导管将水和溶解的矿物质从根部单向向上输送到叶片。韧皮部筛管则将糖类（主要是蔗糖）从叶片运往植物各处，方向可以是双向的。

Transpiration is the loss of water vapour from the stomata. It helps draw water up through the xylem. Factors like wind, temperature, humidity and light affect transpiration rate.

蒸腾作用是水蒸气从气孔散失的过程，它有助于通过木质部向上吸水。风、温度、湿度和光照等因素都会影响蒸腾速率。

7. Human Digestive System | 人体消化系统

Food provides energy and building materials. Digestion breaks down large, insoluble molecules into small, soluble ones that can be absorbed into the blood.

食物提供能量和构建材料。消化作用把大而不溶的分子分解为小且可溶的分子，这样才能吸收进血液。

Organ	Function	功能
Mouth	Teeth break food mechanically; saliva contains amylase to begin starch digestion.	牙齿机械咀嚼；唾液含淀粉酶，开始消化淀粉。
Stomach	Churns food and mixes it with acid and protease enzymes to digest proteins.	搅拌食物，将其与胃酸和蛋白酶混合以消化蛋白质。
Small intestine	Chemical digestion by enzymes (amylase, protease, lipase); absorption of nutrients into the blood.	在酶（淀粉酶、蛋白酶、脂肪酶）作用下完成化学消化；营养物质吸收入血。
Large intestine	Absorbs water and forms faeces.	吸收水分，形成粪便。

Accessory organs like the liver produce bile (which helps digest fats), and the pancreas produces digestive enzymes. Dietary fibre, though not digested, helps move food through the gut.

肝脏等附属器官产生胆汁（帮助消化脂肪），胰腺分泌消化酶。膳食纤维虽然不被消化，但有助于推动食物通过肠道。

8. Circulatory and Respiratory Systems | 循环系统与呼吸系统

The circulatory system consists of the heart, blood vessels and blood. It transports oxygen, nutrients, hormones and waste. The heart is a muscular pump with four chambers: right atrium, right ventricle, left atrium and left ventricle.

循环系统由心脏、血管和血液组成，运输氧气、营养物质、激素和废物。心脏是一个肌肉泵，有四个腔室：右心房、右心室、左心房和左心室。

Arteries carry blood away from the heart (usually oxygenated, except the pulmonary artery). Veins return blood to the heart. Capillaries are tiny vessels where substances are exchanged with cells.

动脉将血液带离心脏（除肺动脉外通常含氧血），静脉将血液送回心脏。毛细血管是微小的血管，在此与细胞进行物质交换。

The respiratory system brings oxygen into the body and removes carbon dioxide. Air travels through the trachea, bronchi and bronchioles to reach the alveoli, where gas exchange occurs. Alveoli have thin walls and a large surface area.

呼吸系统将氧气带入体内并排出二氧化碳。空气经过气管、支气管和细支气管到达肺泡，在此进行气体交换。肺泡壁薄，表面积大。

Inhaled air contains about 21% oxygen and very little carbon dioxide; exhaled air contains less oxygen and about 4% carbon dioxide, plus more water vapour.

吸入的空气含约21%的氧气和微量二氧化碳；呼出的空气含氧量降低，二氧化碳含量约4%，同时水蒸气增加。

9. Reproduction and Puberty | 生殖与青春期

Humans reproduce sexually. The male reproductive system produces sperm in the testes; the female system releases eggs (ova) from the ovaries. Fertilisation occurs when a sperm cell fuses with an egg cell in the oviduct, forming a zygote.

人类进行有性生殖。男性生殖系统的睾丸产生精子；女性生殖系统的卵巢排出卵子。精子在输卵管内与卵细胞融合形成受精卵，即为受精。

Puberty is the stage when a child’s body matures into an adult body capable of reproduction. Hormones trigger physical changes: growth of body hair, voice deepening in boys, breast development and menstruation in girls.

青春期是儿童身体发育为具备生殖能力的成年个体的阶段。激素引发身体变化：体毛生长、男孩声音变低沉、女孩乳房发育及月经来潮。

The menstrual cycle lasts about 28 days and involves the monthly release of an egg and thickening of the uterus lining. If fertilisation does not occur, the lining is shed during menstruation.

月经周期大约为28天，包括每月排出一枚卵子和子宫内膜增厚。若未受精，内膜在月经期间脱落。

10. Ecosystems, Habitats and Populations | 生态系统、栖息地与种群

An ecosystem is a community of interacting organisms and their physical environment. A habitat is the place where an organism lives. A population is a group of individuals of the same species living in the same area.

生态系统是由相互作用的生物群落及其物理环境组成的整体。栖息地是生物生活的地方。种群是指生活在同一区域、同一物种的一群个体。

Within a community, species depend on each other. Ecological terms include: producer (makes its own food via photosynthesis), consumer (eats other organisms), and decomposer (breaks down dead material).

在群落内部，物种互相依赖。生态学术语包括：生产者（通过光合作用制造食物）、消费者（吃其他生物）和分解者（分解死亡物质）。

Sample methods such as quadrats and pitfall traps are used to estimate population size and distribution. Biotic factors (living) and abiotic factors (non-living, e.g., temperature, light, pH) affect what lives in a habitat.

样方和陷阱等取样方法可用于估算种群大小和分布。生物因素（活的）和非生物因素（非活的，如温度、光照、pH）影响栖息地中的生物种类。

11. Food Chains, Food Webs and Energy Flow | 食物链、食物网与能量流动

A food chain shows the feeding relationship: energy is passed from the producer to primary consumer, then to secondary consumer, and so on. Arrows show the direction of energy transfer.

食物链显示了取食关系：能量从生产者传递至初级消费者，再到次级消费者等。箭头指向能量传递的方向。

A simple example: grass → grasshopper → frog → snake → hawk. Energy is lost at each trophic level as heat, movement and waste, so food chains rarely have more than four or five links.

简单示例：草 → 蚱蜢 → 青蛙 → 蛇 → 鹰。每个营养级都有能量以热、运动和废物形式散失，因此食物链很少超过4～5级。

A food web is a network of interconnected food chains. It gives a more realistic picture of energy flow and feeding relationships in an ecosystem. If one species is removed, the web can collapse or shift.

食物网是由多条相互关联的食物链组成的网络，它更真实地反映生态系统中的能量流动和取食关系。若某一物种消失，食物网可能崩溃或发生改变。

Decomposers such as bacteria and fungi break down dead matter and recycle nutrients back into the soil, making them available to plants again.

分解者如细菌和真菌分解死物质，将养分循环回土壤，供植物再次利用。

12. Adaptation and Variation | 适应与变异

Adaptations are features that help an organism survive in its environment. They can be structural (e.g., a camel’s hump for fat storage), behavioural (e.g., birds migrating), or functional (e.g., sweating to cool down).

适应是指帮助生物在环境中生存的特征。这些适应可以是结构性的（如骆驼的驼峰储存脂肪）、行为性的（如鸟类迁徙）或功能性的（如出汗降温）。

Extreme environments produce striking adaptations: polar bears have thick fur and blubber for insulation; cacti have spines to reduce water loss and shallow, widespread roots to capture rain.

极端环境造就了显著的适应性：北极熊有厚毛和脂肪层保暖；仙人掌有刺以减少水分丧失，根系浅而广以吸收雨水。

Variation is the difference between individuals of the same species. It can be continuous (height, weight) or discontinuous (blood group, tongue-rolling). Genetic variation arises from differences in genes; environmental variation comes from lifestyle and surroundings.

变异是同一物种个体之间的差异，可分为连续变异（如身高、体重）和不连续变异（如血型、卷舌）。遗传变异源自基因差异，环境变异则由生活方式和周围环境造成。

Natural selection, proposed by Charles Darwin, explains how organisms with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation.

查尔斯·达尔文提出的自然选择学说解释了：具有有利性状的个体更有可能存活并繁殖，从而将这些性状传给下一代。

Published by TutorHao | Biology Revision Series | aleveler.com

更多咨询请联系16621398022（同微信）

Core Knowledge Overview for Year 7 Cambridge Biology | 核心知识点梳理