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Glossary of key terms

Every key term covered across the KS3 Biology and Geography lessons on this site, in one place. 480 terms so far — more get added as lesson files are updated.

2

2D model: A flat, two-dimensional representation, such as a textbook diagram
Related: 3D model · Cell membrane · Cytoplasm · DNA · Evaluation · Mitochondria
Covered in: Animal Cell Structures and Their Functions

3

3D model: A three-dimensional representation showing length, width and depth
Related: 2D model · Cell membrane · Cytoplasm · DNA · Evaluation · Mitochondria
Covered in: Animal Cell Structures and Their Functions

A

Abrasion: An erosion process where the sea uses waves to fire sand, shingle, pebbles, and boulders straight at the cliff face like sandpaper
Related: Arch · Attrition · Cave · Coastal erosion · Hydraulic action · Solution
Covered in: Coastal Erosion
Absorption: When small, soluble food molecules pass through the wall of the small intestine and into the blood
Related: Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion · Fatty acids
Covered in: Absorption and Transport of Nutrients
Active site: The specially shaped area of an enzyme that the substrate fits into
Related: Amylase · Carbohydrase · Catalyst · Denatured · Enzyme · Lipase
Covered in: Digestive Enzymes
Adaptation Biology: A special feature or characteristic that helps an organism function and survive in its environment
Related: Cell membrane · Cell Wall · Chlorophyll · Chloroplast · Cytoplasm · Mitochondria
Covered in: Multicellular and Unicellular Organisms · Plant Adaptations for Photosynthesis
Adaptation Geography: Learning to live with the effects of climate change, such as building flood defences
Related: Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials · Global cooling
Covered in: Climate Change
Adult stem cells: Unspecialized cells found in specific regions of children and adults that can only differentiate into a limited number of related cell types
Related: Bone marrow · Differentiation · Embryonic stem cells · Induced stem cells · Mitosis · Stem cells
Covered in: Stem Cells in Animals
Agriculture: Using land to raise animals or grow crops
Related: Biodiversity · Deforestation · Ecosystem · Habitat
Covered in: Agriculture and Habitat Loss
Air mass: An enormous body of air that acquires specific temperature and moisture characteristics based on where it formed
Related: Altitude · Latitude · Precipitation · Rain shadow · Relief rainfall · Temperate maritime climate
Covered in: The UK's Climate
Air Sacs: Tiny structures at the end of lung tubes where gas exchange happens
Related: Breathing · Carbon Dioxide · Cellular Respiration · Diffusion · Gas Exchange · Lungs
Covered in: Breathing, Respiration and Gas Exchange
Algae: Simple plant-like living things, from tiny ones drifting in the oceans to big seaweeds, that make their own food
Related: Arrow · Consumer · Food chain · Model · Photosynthesis · Population
Covered in: Food Chains
Altitude: The height of land above sea level, which significantly influences local weather patterns and rainfall while causing the temperature to drop by roughly one degree Celsius for every hundred metres gained
Related: Air mass · Climate zone · Equatorial zone · Latitude · Ocean current · Polar zone
Covered in: The UK's Climate · World Climate Zones
Alveoli: Tiny air sacs at the ends of the bronchioles
Related: Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system · Contract
Covered in: The Human Gas Exchange System and Breathing
Amino acids: The small building blocks released when proteins are broken down during mechanical and chemical digestion, which are then absorbed into the blood as soluble nutrients and rebuilt into new proteins for growth and repair
Related: Absorption · Carbohydrate · Chemical digestion · Churning · Circulatory system · Concentration gradient
Covered in: Absorption and Transport of Nutrients · Mechanical and Chemical Digestion
Amylase: A carbohydrase that breaks down starch
Related: Active site · Carbohydrase · Catalyst · Denatured · Enzyme · Lipase
Covered in: Digestive Enzymes
Anther: The part of the stamen that makes and stores pollen
Related: Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament · Gamete
Covered in: Flower Structure · Pollination and Fertilisation
Anthropocene: A proposed new geological epoch, whose name means "the human epoch", where human activity has become the main force shaping Earth's climate, ecosystems and rocks
Related: Archean · Cenozoic · Eon · Epoch · Era · Fossil
Covered in: Geological Timescales · What is the Anthropocene?
Antibiotics: Drugs that target and destroy bacteria specifically, ineffective against viruses
Related: Disease · Fungicide · Infectious disease · Measles · MMR vaccine · Non-infectious disease
Covered in: Infectious and Non-Infectious Diseases
Anus: A ring of muscle that controls the exit of faeces from the body
Related: Bile · Digestive system · Fibre · Gland · Hydrochloric acid · Large intestine
Covered in: The Human Digestive System
Aquifers: Underground water sources that can be affected by over-extraction
Related: Atmosphere · Biodiversity · Biosphere · Desertification · Geosphere · Hydrosphere
Covered in: Human Impacts on Earth's Systems
Arch: Formed when a cave is worn all the way through a headland to the other side
Related: Abrasion · Attrition · Cave · Coastal erosion · Hydraulic action · Solution
Covered in: Coastal Erosion
Archean: The eon when simple life like bacteria first appeared in the oceans
Related: Anthropocene · Cenozoic · Eon · Epoch · Era · Fossil
Covered in: Geological Timescales
Arid and semi-arid: Dry land, where rain is scarce and hard to rely on
Related: Average · Climate · Dollar Street · GDP per capita · Human geography · Inequality
Covered in: Lives Around the World
Arrow: In a food chain it means "is food for" and points towards the organism doing the eating
Related: Algae · Consumer · Food chain · Model · Photosynthesis · Population
Covered in: Food Chains
Atmosphere Biology: The layer of gases that surrounds a planet
Related: Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect · Greenhouse gases
Covered in: The Greenhouse Effect
Atmosphere Geography: The layer of gases that wraps around our entire planet, providing oxygen and protecting us from space
Related: Aquifers · Biodiversity · Biosphere · Desertification · Geosphere · Hydrosphere
Covered in: Human Impacts on Earth's Systems
Attrition: A process where loose rocks and pebbles being churned around in the waves smash into each other, getting smaller, rounder, and smoother (does not touch the cliff)
Related: Abrasion · Arch · Cave · Coastal erosion · Hydraulic action · Solution
Covered in: Coastal Erosion
Average: A share per person that can hide how unevenly something is spread
Related: Arid and semi-arid · Climate · Dollar Street · GDP per capita · Human geography · Inequality
Covered in: Lives Around the World
Axis tilt: The angle at which the Earth is tilted as it orbits the sun, which is the direct cause of the seasons
Related: Climate · Climate graph · Northern Hemisphere · Precipitation · Southern Hemisphere · Temperate maritime climate
Covered in: Weather and Climate

B

Backwash: The movement of water pulling back down a beach toward the sea under the force of gravity
Related: Constructive waves · Destructive waves · Fetch · Swash · Tides · Waves
Covered in: Waves and Tides
Balanced diet: Eating the right amount of each food group so the body gets everything it needs
Related: Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group · Iron
Covered in: Balanced Diet
Beach: The area of land lying between the high tide mark and the low tide mark
Related: Cliff · Coastline · Fishing industry · Shingle · Tourism · Visitor economy
Covered in: The UK Coastline
Behavioural Differences: Behavioural differences are about what animals do, such as when they are active, migration, hibernation, predation, and what they eat
Related: Binomial Name · Carnivore · Class · Classification · Deciduous · Evergreen
Covered in: Classification and Species
Bell jar model: A chest model: a jar for the ribcage, balloons for the lungs and a rubber sheet for the diaphragm
Related: Alveoli · Bronchi · Bronchioles · Bronchus · Circulatory system · Contract
Covered in: The Human Gas Exchange System and Breathing
Bile: A liquid made by the liver that breaks fats into tiny droplets, giving lipase enzymes a bigger surface to work on
Related: Anus · Digestive system · Fibre · Gland · Hydrochloric acid · Large intestine
Covered in: The Human Digestive System
Binomial Name: A unique two-part Latin name for every species made up of its genus followed by its species
Related: Behavioural Differences · Carnivore · Class · Classification · Deciduous · Evergreen
Covered in: Classification and Species
Biodiversity Biology: The range of different species living in an ecosystem
Related: Agriculture · Deforestation · Ecosystem · Habitat
Covered in: Agriculture and Habitat Loss
Biodiversity Geography: The variety of life within the biosphere, which is reduced by habitat destruction
Related: Aquifers · Atmosphere · Biosphere · Desertification · Geosphere · Hydrosphere
Covered in: Human Impacts on Earth's Systems
Biomass: The total mass of living biological organisms in a given area, full of carbon-based molecules built from glucose
Related: Carbon cycle · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis · Precipitation
Covered in: Deforestation and the Carbon and Water Cycles
Biome: A large region of the world where places share a similar climate, plants and animals
Related: Canopy · Climate · Climate change · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome · What is Geography?
Biosphere: Every living thing on the planet, including plants, animals, bacteria, fungi, and their ecosystems
Related: Aquifers · Atmosphere · Biodiversity · Desertification · Geosphere · Hydrosphere
Covered in: Human Impacts on Earth's Systems
Birth rate: The number of live births per thousand people per year
Related: Death rate · Family planning · Natural decrease · Natural increase · Population · Population explosion
Covered in: Our Global Population
Blue Zones: Specific places on Earth where living to a hundred is genuinely normal due to shared lifestyle habits
Related: Disease · Health · Mental health · Physical health · Symptom
Covered in: Good and Ill Health
Bone marrow: The soft, jelly-like living tissue inside bones packed with stem cells that constantly produce new blood cells
Related: Adult stem cells · Differentiation · Embryonic stem cells · Induced stem cells · Mitosis · Stem cells
Covered in: Stem Cells in Animals
Boreal forest: Also known as taiga, a cold-climate evergreen forest found exclusively in the Northern Hemisphere near the poles
Related: Carbon storage · Habitat · Interception · Temperate forest · Tropical rainforest
Covered in: The Forests of the World
Breathing: The process in which air moves in and out of the lungs
Related: Air Sacs · Carbon Dioxide · Cellular Respiration · Diffusion · Gas Exchange · Lungs
Covered in: Breathing, Respiration and Gas Exchange
Bronchi: The two tubes the trachea splits into, one going into each lung
Related: Alveoli · Bell jar model · Bronchioles · Bronchus · Circulatory system · Contract
Covered in: The Human Gas Exchange System and Breathing
Bronchioles: Smaller and smaller branching tubes inside the lungs, like the twigs on a tree
Related: Alveoli · Bell jar model · Bronchi · Bronchus · Circulatory system · Contract
Covered in: The Human Gas Exchange System and Breathing
Bronchus: One of the two bronchi on its own
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Circulatory system · Contract
Covered in: The Human Gas Exchange System and Breathing
Butler's model: A geographical framework illustrating the seven stages a tourist destination typically experiences over time
Related: Consolidation stage · Decline stage · Development stage · Domestic tourism · Exploration stage · International tourism
Covered in: Introduction to Tourism

C

C. difficile: A bacterium that can infect the gut, often after antibiotics, causing severe diarrhoea
Related: Cell Wall · Competition · Cytoplasm · Digestion · DNA · E. coli
Covered in: Bacteria in the Digestive System
Calcium: Builds strong bones and teeth
Related: Balanced diet · Carbohydrates · Eatwell Guide · Fibre · Food group · Iron
Covered in: Balanced Diet
Canopy: A thick, tangled roof of leaves and branches about 30 metres up
Related: Biome · Climate · Condensation · Convectional rainfall · Decomposers · Emergent layer
Covered in: The Tropical Rainforest Biome
Carbohydrase: An enzyme that breaks down carbohydrates into sugars
Related: Active site · Amylase · Catalyst · Denatured · Enzyme · Lipase
Covered in: Digestive Enzymes
Carbohydrate: A food molecule made of sugars joined together that serve as a primary source of energy; they include the specific sugars (like glucose) that plants produce for energy and growth, as well as the molecules broken down in animals during mechanical and chemical digestion
Related: Amino acids · Cellular Respiration · Chemical digestion · Churning · Consumer · Digestion
Covered in: Mechanical and Chemical Digestion · Plant Nutrition
Carbohydrates: Broken down into sugars that fuel the body's cells and muscles
Related: Balanced diet · Calcium · Eatwell Guide · Fibre · Food group · Iron
Covered in: Balanced Diet
Carbon cycle: The constant movement of carbon between the atmosphere, living organisms, the soil, and deep underground
Related: Biomass · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis · Precipitation
Covered in: Deforestation and the Carbon and Water Cycles
Carbon Dioxide: A gas that makes up only about 0.04% of the air; it is a waste product of respiration, removed when you breathe out, and a greenhouse gas
Related: Air Sacs · Atmosphere · Breathing · Cellular Respiration · Diffusion · Emissions
Covered in: Breathing, Respiration and Gas Exchange · The Greenhouse Effect
Carbon storage: The locking away of carbon inside trees absorbed during photosynthesis, helping to reduce atmospheric global warming
Related: Boreal forest · Habitat · Interception · Temperate forest · Tropical rainforest
Covered in: The Forests of the World
Carnivore: Eats only other animals
Related: Behavioural Differences · Binomial Name · Class · Classification · Deciduous · Evergreen
Covered in: Classification and Species
Catalyst: A substance that speeds up a chemical reaction without being used up
Related: Active site · Amylase · Carbohydrase · Denatured · Enzyme · Lipase
Covered in: Digestive Enzymes
Cave: A hollow carved through a headland when hydraulic action opens up a crack and abrasion widens it
Related: Abrasion · Arch · Attrition · Coastal erosion · Hydraulic action · Solution
Covered in: Coastal Erosion
Cell membrane: The cell membrane is the thin, outer layer surrounding the cell and its cytoplasm—found in both animal and plant cell structures, as well as in multicellular and unicellular organisms—that serves to protect the cell and control which substances enter and leave it
Related: 2D model · 3D model · Adaptation · Cell Wall · Chlorophyll · Chloroplast
Covered in: Animal Cell Structures and Their Functions · Multicellular and Unicellular Organisms · Plant Adaptations for Photosynthesis
Cell Wall: A tough, rigid outer layer—found surrounding the cell membrane in plants, bacteria, yeast, and other unicellular organisms, but completely absent in animal cells—that acts like structural scaffolding to provide strength, shape, and vital protection against bursting or damage
Related: Adaptation · C. difficile · Cell membrane · Chlorophyll · Chloroplast · Competition
Covered in: Bacteria in the Digestive System · Multicellular and Unicellular Organisms · Plant Adaptations for Photosynthesis
Cellular Respiration: A chemical process that happens inside the cells of all living things—both plants and animals. It takes the sugar (glucose) from food and breaks it down using oxygen to release the stored energy that cells need to live, grow, and function
Related: Air Sacs · Breathing · Carbohydrate · Carbon Dioxide · Consumer · Diffusion
Covered in: Breathing, Respiration and Gas Exchange · Plant Nutrition
Cenozoic: Our current era, the age of mammals; its name means new life
Related: Anthropocene · Archean · Eon · Epoch · Era · Fossil
Covered in: Geological Timescales
Chemical digestion: Using chemicals to break large food molecules into smaller ones
Related: Amino acids · Carbohydrate · Churning · Digestion · Enzyme · Fatty acids and glycerol
Covered in: Mechanical and Chemical Digestion
Chlorophyll: The green substance inside chloroplasts that absorbs light energy
Related: Adaptation · Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Mitochondria
Covered in: Plant Adaptations for Photosynthesis
Chloroplast: A microscopic green structure found inside plant cells—especially packed within leaves—where photosynthesis takes place by trapping sunlight to make food for the plant
Related: Adaptation · Cell membrane · Cell Wall · Chlorophyll · Cytoplasm · Glucose
Covered in: Multicellular and Unicellular Organisms · Photosynthesis · Plant Adaptations for Photosynthesis
Chromosomes: Bundles of DNA stored in the nucleus
Related: Anther · Cross-pollination · Embryo · Fertilisation · Filament · Gamete
Covered in: Pollination and Fertilisation
Churning: The stomach squeezing and turning food over to break it into smaller pieces
Related: Amino acids · Carbohydrate · Chemical digestion · Digestion · Enzyme · Fatty acids and glycerol
Covered in: Mechanical and Chemical Digestion
Circulatory system: The organ system made up of the heart and blood vessels, which pumps blood around the body to carry oxygen and nutrients to the cells and take waste away
Related: Absorption · Alveoli · Amino acids · Bell jar model · Bronchi · Bronchioles
Covered in: Absorption and Transport of Nutrients · The Human Gas Exchange System and Breathing
City: A settlement with a large population, hospitals, colleges, train and bus networks, and a wide variety of jobs
Related: Global city · Hamlet · Megacity · Natural increase · Rural-to-urban migration · Settlement hierarchy
Covered in: The Growth of Cities
Clark Fisher Model: A model that explains how countries change their employment structures and move through pre-industrial, industrial, and post-industrial phases over time
Related: De-industrialisation · Offshoring · Primary industry · Quaternary industry · Secondary industry · Tertiary industry
Covered in: Types of Industry
Class: The third level down in classification, where an animal like a lion is classified as a mammal
Related: Behavioural Differences · Binomial Name · Carnivore · Classification · Deciduous · Evergreen
Covered in: Classification and Species
Classification: The process of sorting organisms into groups based on their features
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Deciduous · Evergreen
Covered in: Classification and Species
Cliff: A steep rock face along the coast, worn back over time as waves erode its base
Related: Beach · Coastline · Fishing industry · Shingle · Tourism · Visitor economy
Covered in: The UK Coastline
Climate: The average weather of a place, measured over a long period of time, usually 30 years or more
Related: Arid and semi-arid · Average · Axis tilt · Biome · Canopy · Climate graph
Covered in: Lives Around the World · The Tropical Rainforest Biome · Weather and Climate
Climate change: A large-scale, long-term shift in Earth's weather patterns and average temperatures, which is caused primarily by human activities that release greenhouse gases into the atmosphere
Related: Adaptation · Biome · Deforestation · Development · Ecosystem · Enhanced greenhouse effect
Covered in: Climate Change · What is Geography?
Climate graph: A visual chart that displays two sets of data at once—temperature (using a red line and the left y-axis) and precipitation (using blue bars and the right y-axis) for each month of the year
Related: Axis tilt · Climate · Northern Hemisphere · Precipitation · Southern Hemisphere · Temperate maritime climate
Covered in: Weather and Climate
Climate zone: A large band of the planet sharing roughly the same long-term climate characteristics, arranged in neat belts running east to west
Related: Altitude · Equatorial zone · Latitude · Ocean current · Polar zone · Temperate zone
Covered in: World Climate Zones
CLOCC: A five-letter method for describing where a place is, using continent, latitude, ocean or sea, countries or cities nearby, and compass directions
Related: Continent · Equator · Latitude · Northern Hemisphere · Ocean · Physical map
Covered in: Locational Knowledge of the World
Closed system: A system where no new matter enters and none leaves, meaning the global amount of water remains constant and is endlessly recycled
Related: Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow · Hydrological cycle
Covered in: The Water Cycle
Coastal erosion: The wearing away and breaking down of rock, soil, and sediment at the coast by the action of the sea, followed by the movement of that broken material
Related: Abrasion · Arch · Attrition · Cave · Hydraulic action · Solution
Covered in: Coastal Erosion
Coastline: The boundary where solid ground meets the sea or ocean
Related: Beach · Cliff · Fishing industry · Shingle · Tourism · Visitor economy
Covered in: The UK Coastline
Colonisation: When a country is ruled by another nation that imposes its own laws, language, culture, and religion
Related: Diverse society · Globalisation · Interconnected · Silk Road · Transnational corporations · World trade
Covered in: Globalisation: An Introduction
Competition: When organisms compete for food and space to live
Related: C. difficile · Cell Wall · Cytoplasm · Digestion · DNA · E. coli
Covered in: Bacteria in the Digestive System
Concentration gradient: The difference in concentration between two areas that causes particles to diffuse
Related: Absorption · Amino acids · Circulatory system · Diffusion · Digestion · Fatty acids
Covered in: Absorption and Transport of Nutrients
Condensation: The process where water vapour cools and turns back into tiny droplets of liquid water, which build clouds
Related: Biome · Canopy · Climate · Closed system · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome · The Water Cycle
Confluence: The exact point where two rivers meet; on a map it's where two blue lines merge into one
Related: Drainage basin · Estuary · Mouth · Source · Spring · Tributary
Covered in: What is a Drainage Basin?
Consolidation stage: The phase where tourism becomes the heart of the local economy
Related: Butler's model · Decline stage · Development stage · Domestic tourism · Exploration stage · International tourism
Covered in: Introduction to Tourism
Constructive waves: Waves with a strong swash and a weak backwash that deposit material and build beaches up over time
Related: Backwash · Destructive waves · Fetch · Swash · Tides · Waves
Covered in: Waves and Tides
Consumer: An organism that gets its food by eating other organisms
Related: Algae · Arrow · Carbohydrate · Cellular Respiration · Food chain · Minerals
Covered in: Food Chains · Plant Nutrition
Continent: A huge area of land, of which there are seven on Earth
Related: CLOCC · Equator · Latitude · Northern Hemisphere · Ocean · Physical map
Covered in: Locational Knowledge of the World
Contract: When a muscle gets shorter and pulls
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Convectional rainfall: Rain caused by heat, as warm, wet air rises, cools and condenses
Related: Biome · Canopy · Climate · Condensation · Decomposers · Emergent layer
Covered in: The Tropical Rainforest Biome
Cross-pollination: Pollen carried to a flower on a different plant of the same species
Related: Anther · Chromosomes · Embryo · Fertilisation · Filament · Gamete
Covered in: Pollination and Fertilisation
Crust: The thinnest and coolest outermost layer of Earth ranging from about 5 kilometres thick under the oceans to about 70 kilometres under mountains where continents and oceans are found
Related: Inner core · Lithosphere · Mantle · Outer core · Pacific Ring of Fire · Plate boundary
Covered in: Inside Earth
Cytoplasm: The jelly-like, fluid-filled substance that fills the interior of a cell—found in plants, animals, bacteria, and all other living organisms—where most of the cell's essential chemical reactions take place
Related: 2D model · 3D model · Adaptation · C. difficile · Cell membrane · Cell Wall
Covered in: Animal Cell Structures and Their Functions · Bacteria in the Digestive System · Multicellular and Unicellular Organisms

D

De-industrialisation: The process of social and economic change where a country or region moves away from manufacturing and secondary industries toward services
Related: Clark Fisher Model · Offshoring · Primary industry · Quaternary industry · Secondary industry · Tertiary industry
Covered in: Types of Industry
Death rate: The number of deaths per thousand people per year
Related: Birth rate · Family planning · Natural decrease · Natural increase · Population · Population explosion
Covered in: Our Global Population
Deciduous: Loses its leaves in autumn
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Evergreen
Covered in: Classification and Species
Decline stage: The phase where visitors drift away to fresher destinations
Related: Butler's model · Consolidation stage · Development stage · Domestic tourism · Exploration stage · International tourism
Covered in: Introduction to Tourism
Decomposers: Living things, like termites, that break down dead leaves into nutrients
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Emergent layer
Covered in: The Tropical Rainforest Biome
Deforestation Biology: Removing forest land to use for farming, housing, or industry
Related: Agriculture · Biodiversity · Ecosystem · Habitat
Covered in: Agriculture and Habitat Loss
Deforestation Geography: Chopping down billions of trees to clear land for farming, reducing nature's carbon dioxide absorbers
Related: Adaptation · Climate change · Enhanced greenhouse effect · Fossil fuels · Glacials · Global cooling
Covered in: Climate Change
Denatured: Describes an enzyme whose active site has permanently changed shape
Related: Active site · Amylase · Carbohydrase · Catalyst · Enzyme · Lipase
Covered in: Digestive Enzymes
Densely populated: A description for an area where a large number of people live packed closely together, such as in towns and cities
Related: Human factors · Physical factors · Population density · Population distribution · Sparsely populated
Covered in: Population Density
Desertification: When land gradually turns into a desert because it becomes too hot and dry to support plants
Related: Aquifers · Atmosphere · Biodiversity · Biosphere · Geosphere · Hydrosphere
Covered in: Human Impacts on Earth's Systems
Destructive waves: Waves with a weak swash and a very strong backwash that drag material away and cause coastal erosion
Related: Backwash · Constructive waves · Fetch · Swash · Tides · Waves
Covered in: Waves and Tides
Development: The process of countries becoming wealthier and improving quality of life
Related: Biome · Climate change · Ecosystem · Environmental geography · Geography · Human geography
Covered in: What is Geography?
Development stage: The phase where hotels, restaurants and big attractions appear, and visitor numbers shoot up
Related: Butler's model · Consolidation stage · Decline stage · Domestic tourism · Exploration stage · International tourism
Covered in: Introduction to Tourism
Diaphragm: A dome-shaped sheet of muscle that sits underneath the lungs
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Differentiation: The process where an unspecialized stem cell changes into a specialized cell with a specific function by switching genes on or off
Related: Adult stem cells · Bone marrow · Embryonic stem cells · Induced stem cells · Mitosis · Stem cells
Covered in: Stem Cells in Animals
Diffusion: The chemical-free, passive process where particles naturally spread out, resulting in a net (overall) movement from an area of higher concentration (where they are crowded) to an area of lower concentration (where there is more space)
Related: Absorption · Air Sacs · Amino acids · Breathing · Carbon Dioxide · Cellular Respiration
Covered in: Absorption and Transport of Nutrients · Breathing, Respiration and Gas Exchange
Digestion: The combination of mechanical and chemical processes that break large pieces of food and large food molecules down into small, soluble ones so they can be easily absorbed into the bloodstream
Related: Absorption · Amino acids · C. difficile · Carbohydrate · Cell Wall · Chemical digestion
Covered in: Absorption and Transport of Nutrients · Bacteria in the Digestive System · Mechanical and Chemical Digestion
Digestive system: A roughly nine-metre-long tube running through the body that breaks food down into tiny nutrients small enough to enter the blood
Related: Anus · Bile · Fibre · Gland · Hydrochloric acid · Large intestine
Covered in: The Human Digestive System
Disease: A persistent deviation from a person's normal health, which noticeably alters their appearance, the way their body functions, or how they behave
Related: Antibiotics · Blue Zones · Fungicide · Health · Infectious disease · Measles
Covered in: Good and Ill Health · Infectious and Non-Infectious Diseases
Distribution: The geographic pattern of how something—such as people, wealth, or natural resources—is spread out or located across a specific region or across different areas around the world
Related: Economic diversification · Economy · Export · Import · Natural resource · Natural resource trap
Covered in: Natural Resources and the Economy in the Middle East · Natural Resources
Diverse society: A society with a wide variety of people, religions, and cultures living side by side
Related: Colonisation · Globalisation · Interconnected · Silk Road · Transnational corporations · World trade
Covered in: Globalisation: An Introduction
DNA: The genetic material that contains all the instructions for a cell's activities; in animal cells, it is safely packed inside a nucleus, whereas in bacteria, it floats freely in the cytoplasm because bacteria do not have a nucleus
Related: 2D model · 3D model · C. difficile · Cell membrane · Cell Wall · Competition
Covered in: Animal Cell Structures and Their Functions · Bacteria in the Digestive System
Dollar Street: A website by Gapminder that photographs family homes and lines them up by income
Related: Arid and semi-arid · Average · Climate · GDP per capita · Human geography · Inequality
Covered in: Lives Around the World
Domestic tourism: Travel for leisure where individuals visit destinations within their own country
Related: Butler's model · Consolidation stage · Decline stage · Development stage · Exploration stage · International tourism
Covered in: Introduction to Tourism
Drainage basin: The whole area of land that drains into one river, including all of its tributaries
Related: Closed system · Condensation · Confluence · Estuary · Evaporation · Groundwater
Covered in: What is a Drainage Basin? · The Water Cycle

E

E. coli: A bacterium that lives in the gut; most types are harmless but some cause food poisoning
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System
Eatwell Guide: A UK government guide showing the proportions of each food group in a balanced diet
Related: Balanced diet · Calcium · Carbohydrates · Fibre · Food group · Iron
Covered in: Balanced Diet
Economic diversification: Adding variety or changing an economy to avoid relying on a single resource or industry
Related: Distribution · Economy · Export · Import · Natural resource · NEOM
Covered in: Natural Resources and the Economy in the Middle East
Economy: The way a country produces, uses, and manages money, jobs, goods, and services
Related: Distribution · Economic diversification · Export · Import · Natural resource · NEOM
Covered in: Natural Resources and the Economy in the Middle East
Ecosystem Biology: A community of living organisms interacting with each other and their environment
Related: Agriculture · Biodiversity · Deforestation · Habitat
Covered in: Agriculture and Habitat Loss
Ecosystem Geography: All living and non-living things in an area working together
Related: Biome · Climate change · Development · Environmental geography · Geography · Human geography
Covered in: What is Geography?
Embryo: What the zygote grows and divides into, before developing inside a seed
Related: Anther · Chromosomes · Cross-pollination · Fertilisation · Filament · Gamete
Covered in: Pollination and Fertilisation
Embryonic stem cells: Master stem cells found in early embryos with unlimited potential to become any type of cell in the body
Related: Adult stem cells · Bone marrow · Differentiation · Induced stem cells · Mitosis · Stem cells
Covered in: Stem Cells in Animals
Emergent layer: The top layer, where a few giant trees poke out above the rest of the forest
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Emissions: Releases of greenhouse gases into the air
Related: Atmosphere · Carbon Dioxide · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect · Greenhouse gases
Covered in: The Greenhouse Effect
Enhanced greenhouse effect Biology: When extra greenhouse gases from human activity trap more heat in the atmosphere, making Earth warmer and speeding up climate change
Related: Atmosphere · Biomass · Carbon cycle · Carbon Dioxide · Emissions · Food security
Covered in: Deforestation and the Carbon and Water Cycles · The Greenhouse Effect
Enhanced greenhouse effect Geography: When human activities release extra greenhouse gases, making the blanket around Earth thicker and trapping more heat
Related: Adaptation · Climate change · Deforestation · Fossil fuels · Glacials · Global cooling
Covered in: Climate Change
Environmental geography: The study of the relationships between people and the environment, focusing on human impacts like climate change, pollution, deforestation, and sustainability
Related: Biome · Climate change · Development · Ecosystem · Geography · Human geography
Covered in: What is Geography?
Enzyme: A specialized biological catalyst—a chemical made by the body—that speeds up the chemical breakdown of large food molecules during digestion
Related: Active site · Amino acids · Amylase · C. difficile · Carbohydrase · Carbohydrate
Covered in: Bacteria in the Digestive System · Digestive Enzymes · Mechanical and Chemical Digestion
Eon: The largest division of geological time, lasting hundreds of millions to billions of years
Related: Anthropocene · Archean · Cenozoic · Epoch · Era · Fossil
Covered in: Geological Timescales · What is the Anthropocene?
Epoch: A division of a period in geological time, lasting thousands to millions of years
Related: Anthropocene · Archean · Cenozoic · Eon · Era · Fossil
Covered in: Geological Timescales · What is the Anthropocene?
Equator: The imaginary line of latitude (0°) running around the middle of the Earth, halfway between the North and South Poles
Related: Biome · Canopy · Climate · CLOCC · Condensation · Continent
Covered in: Locational Knowledge of the World · The Tropical Rainforest Biome
Equatorial zone: A hot and wet climate zone located right along the Equator, home to tropical rainforests
Related: Altitude · Climate zone · Latitude · Ocean current · Polar zone · Temperate zone
Covered in: World Climate Zones
Era: A division of an eon in geological time, lasting tens to hundreds of millions of years
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Fossil
Covered in: Geological Timescales · What is the Anthropocene?
Estuary: An area where fresh river water mixes with salty sea water, often forming mudflats and salt marsh
Related: Confluence · Drainage basin · Mouth · Source · Spring · Tributary
Covered in: What is a Drainage Basin?
Evaluation: Identifying the strengths and weaknesses of a model to see how it could be improved
Related: 2D model · 3D model · Cell membrane · Cytoplasm · DNA · Mitochondria
Covered in: Animal Cell Structures and Their Functions
Evaporation: The process where the sun heats water and turns it from a liquid into a gas (water vapour), which rises into the air
Related: Biome · Canopy · Climate · Closed system · Condensation · Convectional rainfall
Covered in: The Tropical Rainforest Biome · The Water Cycle
Evergreen: A plant that keeps its leaves all year
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Excretion: The removal of waste substances produced by chemical reactions inside an organism's cells
Related: Growth · Life cycle · Movement · Mrs Gren · Nutrition · Organism
Covered in: The 7 Life Processes (MRS GREN)
Exhalation: Breathing out
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Exploration stage: The initial phase of a resort's lifecycle where only a small number of adventurous visitors discover the location
Related: Butler's model · Consolidation stage · Decline stage · Development stage · Domestic tourism · International tourism
Covered in: Introduction to Tourism
Export: Selling goods or services to other countries
Related: Distribution · Economic diversification · Economy · Food miles · Global company · Global supply chain
Covered in: Food Production and Supply Chains · Natural Resources and the Economy in the Middle East

F

Family: The fifth level down in classification, where a lion sits in Felidae, the cat family
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Family planning: Access to contraception and education that allows people to choose when and whether to have children
Related: Birth rate · Death rate · Natural decrease · Natural increase · Population · Population explosion
Covered in: Our Global Population
Fatty acids: Soluble nutrients absorbed into the blood, released from digested fats
Related: Absorption · Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion
Covered in: Absorption and Transport of Nutrients
Fatty acids and glycerol: The two small products released when a fat is digested
Related: Amino acids · Carbohydrate · Chemical digestion · Churning · Digestion · Enzyme
Covered in: Mechanical and Chemical Digestion
Fertile: Can produce offspring that can also reproduce
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Fertilisation: The fusion of the nucleus of a male gamete with the nucleus of the ovum
Related: Anther · Chromosomes · Cross-pollination · Embryo · Filament · Gamete
Covered in: Pollination and Fertilisation
Fetch: The distance a wave has travelled across open water before reaching the shore, which directly influences wave size
Related: Backwash · Constructive waves · Destructive waves · Swash · Tides · Waves
Covered in: Waves and Tides
Fibre: An undigestable part of food that is never broken down into small, soluble nutrients, meaning it cannot be absorbed into the blood; instead, it passes through the body to bulk up waste and keep everything moving smoothly through the digestive system
Related: Absorption · Amino acids · Anus · Balanced diet · Bile · Calcium
Covered in: Absorption and Transport of Nutrients · Balanced Diet · The Human Digestive System
Filament: The thin stalk that holds up the anther
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Gamete
Covered in: Flower Structure · Pollination and Fertilisation
Fishing industry: The catching, processing, and selling of fish and seafood, providing jobs and income for coastal communities
Related: Beach · Cliff · Coastline · Shingle · Tourism · Visitor economy
Covered in: The UK Coastline
Food chain: A diagram showing how food passes from one living thing to the next
Related: Algae · Arrow · Consumer · Model · Photosynthesis · Population
Covered in: Food Chains
Food group: A category of foods that share similar nutritional properties, such as carbohydrates or proteins
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Iron
Covered in: Balanced Diet
Food miles: The distance food travels from where it is grown or made to where it is eaten
Related: Export · Global company · Global supply chain · Globalisation · Greenhouse gases · Import
Covered in: Food Production and Supply Chains
Food security: Having reliable access to a sufficient quantity of affordable, nutritious food
Related: Biomass · Carbon cycle · Enhanced greenhouse effect · Fossil fuels · Photosynthesis · Precipitation
Covered in: Deforestation and the Carbon and Water Cycles
Forest floor: The bottom layer, covered in fallen leaves and home to decomposers
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Fossil: The remains of a living thing trapped in rock layers, recording Earth's history like a diary
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Fossil fuels Biology: Coal, oil and natural gas, formed from the remains of organisms that lived millions of years ago; burning them releases carbon dioxide
Related: Atmosphere · Biomass · Carbon cycle · Carbon Dioxide · Emissions · Enhanced greenhouse effect
Covered in: Deforestation and the Carbon and Water Cycles · The Greenhouse Effect
Fossil fuels Geography: Fuels like coal, oil, and gas that release trapped carbon dioxide when burned
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Glacials · Global cooling
Covered in: Climate Change
Fungicide: A chemical that targets and kills fungal infections, literally meaning "fungus killer"
Related: Antibiotics · Disease · Infectious disease · Measles · MMR vaccine · Non-infectious disease
Covered in: Infectious and Non-Infectious Diseases

G

Gamete: A sex cell that holds half of the DNA needed to make a new plant
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Gametes: Sex cells that carry half the genetic information of a parent plant
Related: Anther · Filament · Ova · Ovary · Ovules · Producers
Covered in: Flower Structure
Gas Exchange: Oxygen diffuses from lungs into blood; carbon dioxide diffuses from blood into lungs
Related: Air Sacs · Breathing · Carbon Dioxide · Cellular Respiration · Diffusion · Lungs
Covered in: Breathing, Respiration and Gas Exchange
Gas exchange system: A group of organs that work together so you can breathe, also called the respiratory system
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
GDP per capita: The value of goods and services a country produces in a year, divided by its population
Related: Arid and semi-arid · Average · Climate · Dollar Street · Human geography · Inequality
Covered in: Lives Around the World
Genus: The sixth level down in classification, which is the first part of a binomial name
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Geography: The study of Earth's landscapes, people, places, and environments
Related: Biome · Climate change · Development · Ecosystem · Environmental geography · Human geography
Covered in: What is Geography?
Geological timescale: The timeline of Earth's history, split into sections of very different lengths
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Geosphere: The solid parts of Earth, including the crust, mantle, core, rocks, soil, mountains, and landforms
Related: Aquifers · Atmosphere · Biodiversity · Biosphere · Desertification · Hydrosphere
Covered in: Human Impacts on Earth's Systems
Germination: When a seed starts to grow a root, a shoot and leaves
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Glacials: Periods of freezing cold where ice covered huge parts of the planet
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Global cooling
Covered in: Climate Change
Gland: A part of the body that makes and releases chemicals
Related: Anus · Bile · Digestive system · Fibre · Hydrochloric acid · Large intestine
Covered in: The Human Digestive System
Global city: A major urban center at the top of the settlement hierarchy, such as London, New York, or Tokyo, that shapes global business and culture
Related: City · Hamlet · Megacity · Natural increase · Rural-to-urban migration · Settlement hierarchy
Covered in: The Growth of Cities
Global company: A business that operates in more than one country
Related: Export · Food miles · Global supply chain · Globalisation · Greenhouse gases · Import
Covered in: Food Production and Supply Chains
Global cooling: When Earth's temperatures drop
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Global supply chain: A supply chain whose journey crosses several countries
Related: Export · Food miles · Global company · Globalisation · Greenhouse gases · Import
Covered in: Food Production and Supply Chains
Global warming: When Earth's temperatures rise
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Globalisation: The process of the world becoming more interconnected, where places, people, and businesses are linked
Related: Colonisation · Diverse society · Export · Food miles · Global company · Global supply chain
Covered in: Food Production and Supply Chains · Globalisation: An Introduction
Glucose: A single, small sugar molecule—a type of carbohydrate—that serves as a primary source of energy; it is produced by plants during photosynthesis to act as food, and it is released in animals during digestion as a soluble nutrient small enough to be absorbed into the blood
Related: Absorption · Amino acids · Carbohydrate · Chemical digestion · Chloroplast · Churning
Covered in: Absorption and Transport of Nutrients · Mechanical and Chemical Digestion · Photosynthesis
Glycerol: A soluble nutrient absorbed alongside fatty acids from digested fats
Related: Absorption · Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion
Covered in: Absorption and Transport of Nutrients
Great Acceleration: A proposed start date for the Anthropocene in the 1950s following WWII, marked by a population surge, mass plastic production, and radioactive fallout from nuclear tests
Related: Anthropocene · Eon · Epoch · Era · Holocene · Industrial Revolution
Covered in: What is the Anthropocene?
Great Dying: The extinction 252 million years ago, caused by huge volcanic eruptions, that ended the Paleozoic
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Greenhouse effect: Greenhouse gases soaking up heat and sending part back, so heat escapes to space more slowly
Related: Atmosphere · Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse gases
Covered in: The Greenhouse Effect
Greenhouse gases Biology: Gases in the atmosphere that keep it warmer than it would be without them
Related: Atmosphere · Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect
Covered in: The Greenhouse Effect
Greenhouse gases Geography: Gases like carbon dioxide, water vapour, and methane that form a layer around Earth and trap heat
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Export · Food miles
Covered in: Climate Change · Food Production and Supply Chains
Groundwater: Water that is stored deep underground in rock layers
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater flow · Hydrological cycle
Covered in: The Water Cycle
Groundwater flow: The slow movement of groundwater through rock toward a river or the sea
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Hydrological cycle
Covered in: The Water Cycle
Growth: Getting bigger, or repairing damaged parts, sometimes at the cellular level
Related: Excretion · Life cycle · Movement · Mrs Gren · Nutrition · Organism
Covered in: The 7 Life Processes (MRS GREN)
Gut Flora: Bacteria living in your digestive system
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System

H

Habitat Biology: The place where an organism lives, providing it with food, shelter, and a place to reproduce
Related: Agriculture · Biodiversity · Deforestation · Ecosystem
Covered in: Agriculture and Habitat Loss
Habitat Geography: The natural home of a plant or animal, which gives it the food, water and shelter it needs to live
Related: Biome · Boreal forest · Canopy · Carbon storage · Climate · Condensation
Covered in: The Forests of the World · The Tropical Rainforest Biome
Hadean: The first eon, a violent world of volcanoes and meteorites when the first crust formed
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Hamlet: The smallest settlement in the hierarchy — just a handful of homes, often with no shops and maybe not even a school
Related: City · Global city · Megacity · Natural increase · Rural-to-urban migration · Settlement hierarchy
Covered in: The Growth of Cities
Health: A whole range between "well" and "sick" that can shift from one day to the next rather than a simple switch
Related: Blue Zones · Disease · Mental health · Physical health · Symptom
Covered in: Good and Ill Health
Herbivore: Eats only plants
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Heredity: The biological process of passing features from parents down to their offspring through reproduction
Related: Identical twins · Inherited features · Nucleus · Offspring · Reproduction · Variation
Covered in: Heredity
Historical documents: Old paintings, photographs, and diary entries that give clues about past climates
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Holocene: The current geological epoch, which began about 11,700 years ago when the last ice age ended, marked by a warm and stable climate
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales · What is the Anthropocene?
Human factors: Man-made or societal influences such as job opportunities and transport networks that affect settlement patterns
Related: Densely populated · Physical factors · Population density · Population distribution · Sparsely populated
Covered in: Population Density
Human geography: The study of people and the places they live in, such as how societies, cultures, populations, jobs, housing and cities differ around the world
Related: Arid and semi-arid · Average · Biome · Climate · Climate change · Development
Covered in: Lives Around the World · What is Geography?
Hydraulic action: A physical erosion process where a wave slams into a cliff, trapping and violently compressing air inside rock cracks until they widen and break
Related: Abrasion · Arch · Attrition · Cave · Coastal erosion · Solution
Covered in: Coastal Erosion
Hydrochloric acid: A strong chemical secreted by the stomach to break apart food and kill harmful germs
Related: Anus · Bile · Digestive system · Fibre · Gland · Large intestine
Covered in: The Human Digestive System
Hydrological cycle: The continuous movement of water between the ocean, land, rivers, and atmosphere driven by the sun and gravity
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Hydrosphere: All the water on Earth, including oceans, rivers, lakes, glaciers, groundwater, and water vapour
Related: Aquifers · Atmosphere · Biodiversity · Biosphere · Desertification · Geosphere
Covered in: Human Impacts on Earth's Systems

I

Ice core: A long tube of ice drilled in Antarctica, holding bubbles of ancient air
Related: Atmosphere · Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect
Covered in: The Greenhouse Effect
Ice cores: Cylinders of ice extracted from sheets in Greenland and Antarctica containing air bubbles that show ancient atmospheres
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Identical twins: Twins who grow from the same fertilised egg, so they inherit exactly the same genes and look almost the same
Related: Heredity · Inherited features · Nucleus · Offspring · Reproduction · Variation
Covered in: Heredity
Import: An import is a good, material, or service that is bought from another country and brought in from abroad to meet local demand
Related: Distribution · Economic diversification · Economy · Export · Food miles · Global company
Covered in: Food Production and Supply Chains · Natural Resources and the Economy in the Middle East · Natural Resources
Induced stem cells: Specialized cells, such as skin cells, chemically treated to switch back on genes that were turned off, making them behave like stem cells again
Related: Adult stem cells · Bone marrow · Differentiation · Embryonic stem cells · Mitosis · Stem cells
Covered in: Stem Cells in Animals
Industrial Revolution: A proposed start date for the Anthropocene during the late 1700s when factories emerged and carbon dioxide emissions spiked from coal burning
Related: Anthropocene · Eon · Epoch · Era · Great Acceleration · Holocene
Covered in: What is the Anthropocene?
Industrialisation: The turning point starting around the mid-1700s where factories and mass production grew, driven by fossil fuels
Related: Aquifers · Atmosphere · Biodiversity · Biosphere · Desertification · Geosphere
Covered in: Human Impacts on Earth's Systems
Inequality: The uneven sharing of resources, opportunities and living conditions
Related: Arid and semi-arid · Average · Climate · Dollar Street · GDP per capita · Human geography
Covered in: Lives Around the World
Infectious disease: A disease caused by a pathogen that can be passed from one organism to another
Related: Antibiotics · Disease · Fungicide · Measles · MMR vaccine · Non-infectious disease
Covered in: Infectious and Non-Infectious Diseases
Infertile: Cannot reproduce
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Infiltration: The process where water soaking down from the ground surface enters the soil
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Informal settlement: An area where people build their own homes, often without planning or basic services
Related: Arid and semi-arid · Average · Climate · Dollar Street · GDP per capita · Human geography
Covered in: Lives Around the World
Inhalation: Breathing in
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Inherited features: Characteristics passed down from parents to offspring, which can be visible (like eye colour or hair type) or invisible (internal processes)
Related: Heredity · Identical twins · Nucleus · Offspring · Reproduction · Variation
Covered in: Heredity
Inner core: The innermost layer of Earth, made of iron and nickel at around 5,500°C, kept solid by intense pressure
Related: Crust · Lithosphere · Mantle · Outer core · Pacific Ring of Fire · Plate boundary
Covered in: Inside Earth
Insoluble: A substance that does not dissolve in water; in the digestive system, insoluble substances remain as large particles that are too big to pass through the intestine wall into the blood
Related: Absorption · Amino acids · Carbohydrate · Chemical digestion · Churning · Circulatory system
Covered in: Absorption and Transport of Nutrients · Mechanical and Chemical Digestion
Interception: The process in the water cycle where falling precipitation (like raindrops) is caught by vegetation—such as leaves, branches, and trees—before it can reach the ground surface, which helps slow down the flow of water and prevent rapid flooding
Related: Boreal forest · Carbon storage · Closed system · Condensation · Drainage basin · Evaporation
Covered in: The Forests of the World · The Water Cycle
Interconnected: When two or more things are linked to each other and have an impact on each other
Related: Colonisation · Diverse society · Globalisation · Silk Road · Transnational corporations · World trade
Covered in: Globalisation: An Introduction
Intercostal muscles: Muscles in between the ribs that are attached to the ribcage and move it
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Interdependence: When countries depend on each other
Related: Export · Food miles · Global company · Global supply chain · Globalisation · Greenhouse gases
Covered in: Food Production and Supply Chains
Interglacials: Periods of warmth where the ice melted away
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
International tourism: Travel where tourists cross national borders to visit other countries
Related: Butler's model · Consolidation stage · Decline stage · Development stage · Domestic tourism · Exploration stage
Covered in: Introduction to Tourism
Interviews: When people describe their lives in their own words
Related: Arid and semi-arid · Average · Climate · Dollar Street · GDP per capita · Human geography
Covered in: Lives Around the World
Involvement stage: The phase where locals start opening up to tourists
Related: Butler's model · Consolidation stage · Decline stage · Development stage · Domestic tourism · Exploration stage
Covered in: Introduction to Tourism
Iron: Used to make red blood cells, which carry oxygen around the body
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet

K

Kingdom: The largest group in the seven levels of the scientific classification system
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species

L

Large intestine: The organ responsible for pulling water back out of unabsorbed waste to firm it up before it reaches the rectum
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Latitude: The measurement of how far north or south a location is from the Equator, calculated in degrees (°), which dictates how directly sunlight strikes the Earth's surface and shapes local climates
Related: Air mass · Altitude · Climate zone · CLOCC · Continent · Equator
Covered in: Locational Knowledge of the World · The UK's Climate · World Climate Zones
Leaf litter: The fallen leaves that cover the forest floor
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Life cycle: The series of stages an organism passes through from its earliest beginnings, such as a seed or egg, through to adulthood and reproduction
Related: Excretion · Growth · Movement · Mrs Gren · Nutrition · Organism
Covered in: The 7 Life Processes (MRS GREN)
Lipase: An enzyme that breaks down lipids into fatty acids and glycerol
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Lipid: The scientific name for a fat, used by the body for storage and energy
Related: Amino acids · Carbohydrate · Chemical digestion · Churning · Digestion · Enzyme
Covered in: Mechanical and Chemical Digestion
Lipids: Fats used for energy, insulation, and building the membrane around every cell
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet
Lithosphere: The hard, rigid outer layer of Earth formed by the combination of the upper mantle and the crust
Related: Crust · Inner core · Mantle · Outer core · Pacific Ring of Fire · Plate boundary
Covered in: Inside Earth
Liver: An organ that produces bile and sends it into the small intestine to help digest fats
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Living Organisms: Bacteria are alive, just like you and me
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System
Locational knowledge: Knowing where specific places, countries, and physical features are located across the world
Related: Biome · Climate change · Development · Ecosystem · Environmental geography · Geography
Covered in: What is Geography?
Lock and key model: The substrate fits the enzyme's active site perfectly, like a key in a lock
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Lungs: A pair of organs in the chest — the only place breathing happens
Related: Air Sacs · Breathing · Carbon Dioxide · Cellular Respiration · Diffusion · Gas Exchange
Covered in: Breathing, Respiration and Gas Exchange

M

Mantle: Earth's thickest layer at 2,900 kilometres, composed mostly of solid rock with a tiny fraction that flows slowly over long periods
Related: Crust · Inner core · Lithosphere · Outer core · Pacific Ring of Fire · Plate boundary
Covered in: Inside Earth
Mass extinction: An event where a huge share of all species are wiped out
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Measles: An infectious disease caused by a virus, spreading through droplets from coughs and sneezes, preventable by the MMR vaccine
Related: Antibiotics · Disease · Fungicide · Infectious disease · MMR vaccine · Non-infectious disease
Covered in: Infectious and Non-Infectious Diseases
Mechanical digestion: Physically breaking food into smaller pieces without changing it chemically
Related: Amino acids · Carbohydrate · Chemical digestion · Churning · Digestion · Enzyme
Covered in: Mechanical and Chemical Digestion
Megacity: An urban area with a total population of ten million or more people
Related: City · Global city · Hamlet · Natural increase · Rural-to-urban migration · Settlement hierarchy
Covered in: The Growth of Cities
Melting: The process where water moves from ice caps and glaciers into rivers and lakes
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Mental health: How you feel, think, and act, covering your emotions, ability to organise thoughts, and social connections
Related: Blue Zones · Disease · Health · Physical health · Symptom
Covered in: Good and Ill Health
Mesozoic: The middle era of the Phanerozoic, when dinosaurs ruled; its name means middle life
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Methane: A greenhouse gas that cows release, mostly when they burp
Related: Atmosphere · Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect
Covered in: The Greenhouse Effect
Microorganism: A very small organism that can only be seen with a microscope
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System
Migration: The movement of people from one place to another
Related: Biome · Climate change · Development · Ecosystem · Environmental geography · Geography
Covered in: What is Geography?
Milankovitch cycles: Slow, regular changes in Earth's orbit (from nearly circular to more oval and back) and in its tilt and wobble, which cause long-term temperature swings
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Minerals: Nutrients like nitrogen, phosphorus, and potassium absorbed from the soil (often mistaken for "plant food," but act more like vitamins for health rather than an energy source)
Related: Carbohydrate · Cellular Respiration · Consumer · Photosynthesis · Producer · Secondary consumer
Covered in: Plant Nutrition
Mitigation: Taking action to reduce greenhouse gas emissions, such as switching to renewable energy
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Mitochondria: The microscopic powerhouses of the cell—found as subcellular structures inside both plant and animal cells—where cellular respiration takes place by using food and oxygen as fuel to release energy
Related: 2D model · 3D model · Adaptation · Air Sacs · Breathing · Carbon Dioxide
Covered in: Animal Cell Structures and Their Functions · Breathing, Respiration and Gas Exchange · Plant Adaptations for Photosynthesis
Mitosis: The process of cell division where one cell splits into two identical copies
Related: Adult stem cells · Bone marrow · Differentiation · Embryonic stem cells · Induced stem cells · Stem cells
Covered in: Stem Cells in Animals
MMR vaccine: A vaccine that protects against measles, mumps, and rubella
Related: Antibiotics · Disease · Fungicide · Infectious disease · Measles · Non-infectious disease
Covered in: Infectious and Non-Infectious Diseases
Model: A simpler way of showing something complicated, used to help explain difficult ideas
Related: 2D model · 3D model · Algae · Arrow · Cell membrane · Consumer
Covered in: Animal Cell Structures and Their Functions · Food Chains
Mouth Biology: Where digestion begins — teeth cut and grind food, the tongue mixes it, and salivary glands release saliva to soften it
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Mouth Geography: The point where a river finally reaches the sea; on a map it's where the blue line meets the coast
Related: Confluence · Drainage basin · Estuary · Source · Spring · Tributary
Covered in: What is a Drainage Basin?
Movement: An organism moving itself, or parts of itself, from one place to another
Related: Excretion · Growth · Life cycle · Mrs Gren · Nutrition · Organism
Covered in: The 7 Life Processes (MRS GREN)
Mrs Gren: An acronym representing the seven vital life processes: Movement, Reproduction, Sensitivity, Growth, Respiration, Excretion, and Nutrition
Related: Excretion · Growth · Life cycle · Movement · Nutrition · Organism
Covered in: The 7 Life Processes (MRS GREN)
Multicellular organism: A living thing made of many specialized cells working together
Related: Adaptation · Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Organ
Covered in: Multicellular and Unicellular Organisms

N

Natural decrease: When the death rate is higher than the birth rate, causing the population to shrink
Related: Birth rate · Death rate · Family planning · Natural increase · Population · Population explosion
Covered in: Our Global Population
Natural increase: The type of population growth that occurs within a country or city when the birth rate is higher than the death rate, causing the total number of people to grow naturally
Related: Birth rate · City · Death rate · Family planning · Global city · Hamlet
Covered in: Our Global Population · The Growth of Cities
Natural resource: Is any material, substance, or source of energy found in the natural environment that comes from the Earth without human influence and can be used by people to meet their needs
Related: Distribution · Economic diversification · Economy · Export · Import · Natural resource trap
Covered in: Natural Resources and the Economy in the Middle East · Natural Resources
Natural resource trap: A paradox where countries rich in valuable natural resources often struggle to develop economically due to inequality, neglected sectors, and foreign control
Related: Distribution · Import · Natural resource · Non-renewable resource · Renewable resource · Resource curse
Covered in: Natural Resources
Nectar: The sugary drink that bees collect from flowers
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
NEOM: A massive development project in Saudi Arabia featuring innovative regions like The Line, Oxagon, Trojena, and Sindalah
Related: Distribution · Economic diversification · Economy · Export · Import · Natural resource
Covered in: Natural Resources and the Economy in the Middle East
Nitrogen: The most common gas in the air, about 78%; your body does nothing with it, and it does not help keep Earth warm
Related: Air Sacs · Atmosphere · Breathing · Carbon Dioxide · Cellular Respiration · Diffusion
Covered in: Breathing, Respiration and Gas Exchange · The Greenhouse Effect
Non-infectious disease: A disease that cannot be spread between people, typically caused by lifestyle factors or genetics
Related: Antibiotics · Disease · Fungicide · Infectious disease · Measles · MMR vaccine
Covered in: Infectious and Non-Infectious Diseases
Non-renewable resource: A non-renewable resource is a natural resource—such as coal, oil, natural gas, or iron ore—that took millions or billions of years to form deep inside the Earth and cannot be replaced once it is used up
Related: Distribution · Economic diversification · Economy · Export · Import · Natural resource
Covered in: Natural Resources and the Economy in the Middle East · Natural Resources
Northern Hemisphere: The half of the Earth north of the Equator
Related: Axis tilt · Climate · Climate graph · CLOCC · Continent · Equator
Covered in: Locational Knowledge of the World · Weather and Climate
Nucleus: The microscopic control centre found inside both plant and animal cells that contains DNA—the genetic material that stores instructions for all the cell's activities and controls inherited features passed down from parents
Related: 2D model · 3D model · Adaptation · Cell membrane · Cell Wall · Chlorophyll
Covered in: Animal Cell Structures and Their Functions · Heredity · Plant Adaptations for Photosynthesis
Nutrients: The small, soluble substances released from food and used for energy, growth and repair
Related: Amino acids · Carbohydrate · Chemical digestion · Churning · Digestion · Enzyme
Covered in: Mechanical and Chemical Digestion
Nutrition: The process of taking in food or nutrients to provide fuel and energy for all other life processes
Related: Excretion · Growth · Life cycle · Movement · Mrs Gren · Organism
Covered in: The 7 Life Processes (MRS GREN)

O

Ocean: A vast area of salt water between the continents
Related: CLOCC · Continent · Equator · Latitude · Northern Hemisphere · Physical map
Covered in: Locational Knowledge of the World
Ocean current: An enormous river of water drifting across the oceans that shifts heat around the planet, warming or cooling nearby coasts
Related: Altitude · Climate zone · Equatorial zone · Latitude · Polar zone · Temperate zone
Covered in: World Climate Zones
Oesophagus: The muscular tube connecting the mouth to the stomach that uses peristalsis to push food downward
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Offshoring: The practice of moving manufacturing or business processes from high-income countries to lower-cost countries to increase profits
Related: Clark Fisher Model · De-industrialisation · Primary industry · Quaternary industry · Secondary industry · Tertiary industry
Covered in: Types of Industry
Offspring: New living organisms produced by parent organisms of the same species
Related: Heredity · Identical twins · Inherited features · Nucleus · Reproduction · Variation
Covered in: Heredity
Omnivore: Eats both plants and animals
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Open system: A system where matter can enter and leave, such as a local drainage basin where water enters via precipitation and leaves through rivers
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Optimum temperature: The temperature at which an enzyme works fastest
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Order: The fourth level down in classification, where an animal like a lion is classified as a carnivore
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Organ: A structure made of different tissues working together on a shared task
Related: Adaptation · Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Multicellular organism
Covered in: Multicellular and Unicellular Organisms
Organ system: A group of organs working together to carry out a major job for the organism
Related: Adaptation · Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Multicellular organism
Covered in: Multicellular and Unicellular Organisms
Organism: Any individual living creature, plant, fungus, or microscopic single-celled life form capable of carrying out life processes
Related: Excretion · Growth · Life cycle · Movement · Mrs Gren · Nutrition
Covered in: The 7 Life Processes (MRS GREN)
Outer core: A liquid metal layer surrounding the inner core
Related: Crust · Inner core · Lithosphere · Mantle · Pacific Ring of Fire · Plate boundary
Covered in: Inside Earth
Ova: The female gametes (singular: ovum)
Related: Anther · Filament · Gametes · Ovary · Ovules · Producers
Covered in: Flower Structure
Ovary: The part at the base of the flower that contains the ovules and protects them
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Flower Structure · Pollination and Fertilisation
Ovule: The part inside the ovary that holds the ovum
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Ovules: Structures located inside the ovary where the female gametes (ova) are produced
Related: Anther · Filament · Gametes · Ova · Ovary · Producers
Covered in: Flower Structure
Ovum: The female gamete, found inside the ovary
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Oxygen: A gas that makes up about 21% of the air; your cells need it for respiration, and it does not help keep Earth warm
Related: Air Sacs · Atmosphere · Breathing · Carbon Dioxide · Cellular Respiration · Diffusion
Covered in: Breathing, Respiration and Gas Exchange · The Greenhouse Effect

P

Pacific Ring of Fire: A tectonically active region around the Pacific Ocean containing about three-quarters of the world's volcanoes and nine out of ten earthquakes
Related: Crust · Inner core · Lithosphere · Mantle · Outer core · Plate boundary
Covered in: Inside Earth
Paleozoic: The first era of the Phanerozoic; its name means ancient life
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Palisade cell: A specialized plant cell found near the top surface of leaves, densely packed with chloroplasts to absorb maximum sunlight
Related: Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Mitochondria · Nucleus
Covered in: Plant Cell Structures and Their Functions
Pancreas: A small organ behind the stomach that makes digestive enzymes and releases them into the small intestine, without food ever passing through it
Related: Active site · Amylase · Anus · Bile · Carbohydrase · Catalyst
Covered in: Digestive Enzymes · The Human Digestive System
Pangaea: One giant supercontinent formed when the land joined together
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Parts per million: How many particles out of every million in the air are carbon dioxide
Related: Atmosphere · Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect
Covered in: The Greenhouse Effect
Pathogen: A microscopic organism—such as a virus, bacterium, fungus, or protist—that enters a living body and causes an infectious disease
Related: Antibiotics · C. difficile · Cell Wall · Competition · Cytoplasm · Digestion
Covered in: Bacteria in the Digestive System · Infectious and Non-Infectious Diseases
Percolation: The process where water sinks even deeper from the soil down into the solid rock layers below
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Period: A division of an era in geological time, lasting millions of years
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales · What is the Anthropocene?
Peristalsis: Waves of muscular squeezing that push food along the digestive tract regardless of gravity
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Permanent vacuole: A large fluid-filled sac in the middle of a plant cell that stores water and cell sap, keeping the cell firm
Related: Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Mitochondria · Nucleus
Covered in: Plant Cell Structures and Their Functions
pH: How acidic or alkaline the surroundings are
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Phanerozoic: Our current eon, starting about 540 million years ago; its name means visible life
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Phloem: Specialized living transport cells that distribute sugary water and food from the leaves to all other parts of the plant
Related: Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Mitochondria · Nucleus
Covered in: Plant Cell Structures and Their Functions
Photosynthesis: The vital chemical process used by green plants to manufacture their own food (glucose) inside their leaves by absorbing carbon dioxide from the air and combining it with water using light energy
Related: Algae · Arrow · Biomass · Carbohydrate · Carbon cycle · Cellular Respiration
Covered in: Deforestation and the Carbon and Water Cycles · Food Chains · Photosynthesis
Phylum: The second level down in classification, which includes sorting animals by whether they have a backbone or not
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Physical Differences: Physical differences are things you can see, such as what an animal is covered in, whether it has a backbone or soft body, how many legs it has, and where its eyes are positioned
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Physical factors: Natural elements like climate, soil quality, water availability, and relief that influence where people live
Related: Densely populated · Human factors · Population density · Population distribution · Sparsely populated
Covered in: Population Density
Physical geography: The study of the Earth's natural features and processes, such as rivers, coasts, mountains, volcanoes, weather, climate and ecosystems
Related: Arid and semi-arid · Average · Biome · Climate · Climate change · Development
Covered in: Lives Around the World · What is Geography?
Physical health: The condition of your body, inside and out, including your heart, lungs, digestive system, and bones
Related: Blue Zones · Disease · Health · Mental health · Symptom
Covered in: Good and Ill Health
Physical map: A map showing the land itself, including mountains, rivers and how high the ground is
Related: CLOCC · Continent · Equator · Latitude · Northern Hemisphere · Ocean
Covered in: Locational Knowledge of the World
Plasma: The straw-coloured liquid part of blood that nutrients and waste products dissolve into
Related: Absorption · Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion
Covered in: Absorption and Transport of Nutrients
Plate boundary: The region where two tectonic plates meet, associated with earthquakes and volcanic activity
Related: Crust · Inner core · Lithosphere · Mantle · Outer core · Pacific Ring of Fire
Covered in: Inside Earth
Platelets: Tiny cell fragments carried in the plasma that help blood clot
Related: Absorption · Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion
Covered in: Absorption and Transport of Nutrients
Polar zone: A cold and dry climate zone located near the top and bottom of the Earth around the poles
Related: Altitude · Climate zone · Equatorial zone · Latitude · Ocean current · Temperate zone
Covered in: World Climate Zones
Political map: A map showing the borders between countries, usually with each country in its own colour
Related: CLOCC · Continent · Equator · Latitude · Northern Hemisphere · Ocean
Covered in: Locational Knowledge of the World
Pollen tube: A tube grown by a pollen grain down the style towards the ovary
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Pollination: Transfer of pollen from the anther to the stigma
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Population Biology: A group of organisms of the same type living in the same place
Related: Algae · Arrow · Consumer · Food chain · Model · Photosynthesis
Covered in: Food Chains
Population Geography: The total number of people living in a specific area, such as a city, country, or the entire world
Related: Birth rate · Death rate · Family planning · Natural decrease · Natural increase · Population explosion
Covered in: Our Global Population
Population density: The number of people living in a set area, usually counted per square kilometre
Related: Densely populated · Human factors · Physical factors · Population distribution · Sparsely populated
Covered in: Population Density
Population distribution: The pattern of how people are spread out across a geographic area
Related: Densely populated · Human factors · Physical factors · Population density · Sparsely populated
Covered in: Population Density
Population explosion: The rapid and dramatic acceleration of global population growth driven by sharply falling death rates after 1800
Related: Birth rate · Death rate · Family planning · Natural decrease · Natural increase · Population
Covered in: Our Global Population
Potato blight: An infectious plant disease caused by a fungus, responsible for widespread famine in 1840s Ireland
Related: Antibiotics · Disease · Fungicide · Infectious disease · Measles · MMR vaccine
Covered in: Infectious and Non-Infectious Diseases
Precambrian: The first three eons together, covering nearly 90% of Earth's history
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Precipitation Biology: Rainfall, snow, and hail falling from the sky as part of the water cycle
Related: Biomass · Carbon cycle · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis
Covered in: Deforestation and the Carbon and Water Cycles
Precipitation Geography: Any form of water or moisture—liquid or solid—that falls from the atmosphere back down to Earth's surface, which serves as a vital part of the water cycle and directly shapes local weather and climate patterns
Related: Air mass · Altitude · Axis tilt · Climate · Climate graph · Closed system
Covered in: The UK's Climate · The Water Cycle · Weather and Climate
Pressure: All the tiny pushes from gas molecules hitting the walls of a container, added up
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Primary consumer: The first consumer in a food chain
Related: Algae · Arrow · Consumer · Food chain · Model · Photosynthesis
Covered in: Food Chains
Primary industry: Economic activity that extracts raw materials directly from the Earth or sea, such as farming, fishing, forestry, and mining
Related: Clark Fisher Model · De-industrialisation · Offshoring · Quaternary industry · Secondary industry · Tertiary industry
Covered in: Types of Industry
Processed food: Food that has been changed from its natural state, so it lasts far longer on the shelf
Related: Export · Food miles · Global company · Global supply chain · Globalisation · Greenhouse gases
Covered in: Food Production and Supply Chains
Processing: Changing a food from its natural state
Related: Export · Food miles · Global company · Global supply chain · Globalisation · Greenhouse gases
Covered in: Food Production and Supply Chains
Producer: A living organism—such as a green plant or algae—that manufactures its own food using energy from the environment rather than consuming other living organisms
Related: Algae · Arrow · Carbohydrate · Cellular Respiration · Chloroplast · Consumer
Covered in: Food Chains · Photosynthesis · Plant Nutrition
Producers: Organisms like plants that make their own food using sunlight, water, and carbon dioxide through photosynthesis
Related: Anther · Filament · Gametes · Ova · Ovary · Ovules
Covered in: Flower Structure
Product: A new substance that is formed and comes out of a chemical reaction
Related: Chloroplast · Glucose · Photosynthesis · Producer · Reactant · Stomata
Covered in: Photosynthesis
Protease: An enzyme that breaks down proteins into amino acids
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Protein: A large molecule made of amino acids joined together, used by the body for growth and to repair damaged tissue
Related: Amino acids · Balanced diet · Calcium · Carbohydrate · Carbohydrates · Chemical digestion
Covered in: Balanced Diet · Mechanical and Chemical Digestion
Proterozoic: The eon when oxygen built up in the air and the first life made of many cells appeared
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales

Q

Quaternary: Our current period, the age of ice ages, which began 2.58 million years ago
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Quaternary industry: A knowledge-based and high-tech sector focused on information technology, research and development, computing, and consultancy
Related: Clark Fisher Model · De-industrialisation · Offshoring · Primary industry · Secondary industry · Tertiary industry
Covered in: Types of Industry

R

Rain shadow: A dry area on the leeward side of a mountainous region where air has already dropped most of its moisture
Related: Air mass · Altitude · Latitude · Precipitation · Relief rainfall · Temperate maritime climate
Covered in: The UK's Climate
Raw materials: Things that are grown or dug out of the ground before they are made into anything
Related: Export · Food miles · Global company · Global supply chain · Globalisation · Greenhouse gases
Covered in: Food Production and Supply Chains
Reactant: A substance that goes into a chemical reaction and is changed during the process
Related: Chloroplast · Glucose · Photosynthesis · Producer · Product · Stomata
Covered in: Photosynthesis
Rectum: Where faeces is stored until it leaves the body
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Red blood cells: Cells carried in the plasma that pick up oxygen and carry it around the body
Related: Absorption · Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion
Covered in: Absorption and Transport of Nutrients
Reforestation: Planting trees back in areas where forests have been cleared
Related: Biomass · Carbon cycle · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis
Covered in: Deforestation and the Carbon and Water Cycles
Rejuvenation stage: The potential final phase of Butler's model where a declining resort invests and reinvents itself to attract new crowds
Related: Butler's model · Consolidation stage · Decline stage · Development stage · Domestic tourism · Exploration stage
Covered in: Introduction to Tourism
Relax: When a muscle lets go
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Relief rainfall: Precipitation that occurs when moist air coming off the ocean slams into high ground, is forced upwards, cools, and condenses into clouds
Related: Air mass · Altitude · Latitude · Precipitation · Rain shadow · Temperate maritime climate
Covered in: The UK's Climate
Renewable resource: A renewable resource is a natural resource—such as wind, solar energy, or timber—that naturally replenishes or replaces itself over a relatively short period of time, meaning it will not run out if it is managed sustainably
Related: Distribution · Economic diversification · Economy · Export · Import · Natural resource
Covered in: Natural Resources and the Economy in the Middle East · Natural Resources
Reproduction: Is the biological process by which living things make new living things (known as offspring), serving as one of the seven essential life processes common to all living organisms (MRS GREN)
Related: Excretion · Growth · Heredity · Identical twins · Inherited features · Life cycle
Covered in: Heredity · The 7 Life Processes (MRS GREN)
Resource curse: Another term for the natural resource trap, describing how abundant resources can lead to poor economic development and governance
Related: Distribution · Import · Natural resource · Natural resource trap · Non-renewable resource · Renewable resource
Covered in: Natural Resources
Respiration: A vital chemical reaction that happens inside the cells of all living things, which breaks down food molecules (like glucose) using oxygen to release stored chemical energy. It serves as one of the seven essential life processes (MRS GREN)
Related: 2D model · 3D model · Cell membrane · Cytoplasm · DNA · Evaluation
Covered in: Animal Cell Structures and Their Functions · The 7 Life Processes (MRS GREN)
Ribcage: The protective cage the ribs form around the lungs
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Risk factors: Conditions or behaviours (such as smoking, high blood pressure, or obesity) that significantly increase the likelihood of developing a non-infectious disease
Related: Antibiotics · Disease · Fungicide · Infectious disease · Measles · MMR vaccine
Covered in: Infectious and Non-Infectious Diseases
Root hair cell: A specialized underground plant cell with a long thin extension that massively increases surface area for water and mineral absorption
Related: Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Mitochondria · Nucleus
Covered in: Plant Cell Structures and Their Functions
Rural-to-urban migration: The movement of people from the countryside into towns and cities, driven by better job opportunities and transport links
Related: City · Global city · Hamlet · Megacity · Natural increase · Settlement hierarchy
Covered in: The Growth of Cities

S

Saliva: The liquid in the mouth containing chemicals that begin digesting food
Related: Amino acids · Carbohydrate · Chemical digestion · Churning · Digestion · Enzyme
Covered in: Mechanical and Chemical Digestion
Saturated fat: A less healthy type of fat, found in foods like butter and cake, linked to heart disease
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet
Scale: Tells you how much the real world has been shrunk to fit on a map
Related: CLOCC · Continent · Equator · Latitude · Northern Hemisphere · Ocean
Covered in: Locational Knowledge of the World
Scale bar: A short bar on a map that stands for a real distance, such as a thousand kilometres
Related: CLOCC · Continent · Equator · Latitude · Northern Hemisphere · Ocean
Covered in: Locational Knowledge of the World
Secondary consumer: The second consumer in a food chain, which eats a primary consumer — for example, a human eating a cow that ate grass
Related: Algae · Arrow · Carbohydrate · Cellular Respiration · Consumer · Food chain
Covered in: Food Chains · Plant Nutrition
Secondary industry: Economic activity that takes raw materials from primary industries and manufactures them into finished products
Related: Clark Fisher Model · De-industrialisation · Offshoring · Primary industry · Quaternary industry · Tertiary industry
Covered in: Types of Industry
Seed: What is made after fertilisation, the next generation ready to grow
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Seedling: A young plant that grows from a seed and keeps growing into a new plant
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Seismic waves: Vibrations from earthquakes that ripple through the planet, used by scientists to work out whether Earth's deep layers are solid or liquid
Related: Crust · Inner core · Lithosphere · Mantle · Outer core · Pacific Ring of Fire
Covered in: Inside Earth
Self-pollination: Pollen landing on the stigma of the same flower it came from
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Pollination and Fertilisation
Sensitivity: The ability of a living organism to sense changes in its surroundings and respond to them
Related: Excretion · Growth · Life cycle · Movement · Mrs Gren · Nutrition
Covered in: The 7 Life Processes (MRS GREN)
Settlement hierarchy: A ranking of settlements by population size and the range of services they offer, ranging from hamlets to global cities
Related: City · Global city · Hamlet · Megacity · Natural increase · Rural-to-urban migration
Covered in: The Growth of Cities
Sexual reproduction: A method of reproduction involving two parent plants that contribute DNA through gametes to form a seed
Related: Anther · Filament · Gametes · Ova · Ovary · Ovules
Covered in: Flower Structure
Shingle: Natural beach material made of smooth, round pebbles and stones
Related: Beach · Cliff · Coastline · Fishing industry · Tourism · Visitor economy
Covered in: The UK Coastline
Silk Road: An ancient network of trade routes starting around two thousand years ago that linked Asia to Europe
Related: Colonisation · Diverse society · Globalisation · Interconnected · Transnational corporations · World trade
Covered in: Globalisation: An Introduction
Sixth mass extinction: The current rapid loss of plant and animal species driven primarily by human activities, habitat destruction, and climate change
Related: Anthropocene · Eon · Epoch · Era · Great Acceleration · Holocene
Covered in: What is the Anthropocene?
Small intestine: Is a long, narrow tube that forms the longest section of the human digestive system (measuring around 6 metres in length), where the majority of chemical digestion and almost all nutrient absorption into the blood take place
Related: Absorption · Amino acids · Anus · Bile · Circulatory system · Concentration gradient
Covered in: Absorption and Transport of Nutrients · The Human Digestive System
Small-scale map: A map that shrinks a huge area onto the page, showing more ground but far less detail
Related: CLOCC · Continent · Equator · Latitude · Northern Hemisphere · Ocean
Covered in: Locational Knowledge of the World
Solar radiation: The Sun's energy
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Soluble: A substance that is capable of dissolving in water; in the digestive system, this means it breaks down into individual molecules small enough to pass through the intestine wall and travel easily through the bloodstream
Related: Absorption · Amino acids · Carbohydrate · Chemical digestion · Churning · Circulatory system
Covered in: Absorption and Transport of Nutrients · Mechanical and Chemical Digestion
Solution: A chemical erosion process where weak acids in seawater and rainwater dissolve certain rocks like limestone and chalk into invisible dissolved minerals
Related: Abrasion · Arch · Attrition · Cave · Coastal erosion · Hydraulic action
Covered in: Coastal Erosion
Source: The point where a river begins, often at a spring high in the hills; on a map it's where a blue line starts, usually surrounded by tightly packed contour lines
Related: Confluence · Drainage basin · Estuary · Mouth · Spring · Tributary
Covered in: What is a Drainage Basin?
Southern Hemisphere: The half of the Earth south of the Equator
Related: Axis tilt · Climate · Climate graph · CLOCC · Continent · Equator
Covered in: Locational Knowledge of the World · Weather and Climate
Sparsely populated: A description for an area where very few people are scattered across a large expanse, such as open countryside or deserts
Related: Densely populated · Human factors · Physical factors · Population density · Population distribution
Covered in: Population Density
Species: A group of organisms with very similar features and genes that can reproduce with each other to produce fertile offspring
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Specific: Only works on one type of molecule
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Spring: A point where groundwater is forced back up to the surface, often forming a river's source
Related: Confluence · Drainage basin · Estuary · Mouth · Source · Tributary
Covered in: What is a Drainage Basin?
Stack: An isolated pillar of rock left standing when the roof of an arch collapses under its own weight
Related: Abrasion · Arch · Attrition · Cave · Coastal erosion · Hydraulic action
Covered in: Coastal Erosion
Stagnation stage: The phase where visitor numbers stop growing and the place feels tired and overcrowded
Related: Butler's model · Consolidation stage · Decline stage · Development stage · Domestic tourism · Exploration stage
Covered in: Introduction to Tourism
Stamen: The male part of a flower, made up of the anther and the filament
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Flower Structure · Pollination and Fertilisation
Starch: A substance in starchy foods that is broken down into sugars for energy
Related: Amino acids · Balanced diet · Calcium · Carbohydrate · Carbohydrates · Chemical digestion
Covered in: Balanced Diet · Mechanical and Chemical Digestion
Statistics: Numbers that describe a place, such as income and life expectancy
Related: Arid and semi-arid · Average · Climate · Dollar Street · GDP per capita · Human geography
Covered in: Lives Around the World
Stem cells: Unspecialized cells that have the ability to divide and differentiate into various types of specialized cells
Related: Adult stem cells · Bone marrow · Differentiation · Embryonic stem cells · Induced stem cells · Mitosis
Covered in: Stem Cells in Animals
Stigma: The sticky tip of the female part of the flower that catches pollen grains
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Flower Structure · Pollination and Fertilisation
Stomach: A stretchy bag that holds food and releases hydrochloric acid to break it down and kill germs
Related: Anus · Bile · Digestive system · Fibre · Gland · Hydrochloric acid
Covered in: The Human Digestive System
Stomata: Tiny pores or openings on the surface of leaves through which plants absorb carbon dioxide from the air
Related: Chloroplast · Glucose · Photosynthesis · Producer · Product · Reactant
Covered in: Photosynthesis
Streptococcus pneumoniae: A bacterium that causes pneumonia
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System
Style: The stalk that holds up the stigma and joins it to the ovary
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Flower Structure · Pollination and Fertilisation
Substrate: The molecule that an enzyme works on
Related: Active site · Amylase · Carbohydrase · Catalyst · Denatured · Enzyme
Covered in: Digestive Enzymes
Sunspots: Dark spots on the sun's surface where it is slightly cooler, affecting how much energy the sun gives off
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Supply chain: Every stage involved in producing something, moving it and selling it to customers
Related: Export · Food miles · Global company · Global supply chain · Globalisation · Greenhouse gases
Covered in: Food Production and Supply Chains
Surface area: The total amount of an object's outer surface; increasing it allows more light to be captured by a leaf for photosynthesis, speeds up the rate of nutrient absorption in the gut, and gives digestive chemicals a larger area to work on
Related: Absorption · Adaptation · Amino acids · Carbohydrate · Cell membrane · Cell Wall
Covered in: Absorption and Transport of Nutrients · Mechanical and Chemical Digestion · Plant Adaptations for Photosynthesis
Surface runoff Biology: Water flowing downhill across the ground into rivers and eventually the oceans
Related: Biomass · Carbon cycle · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis
Covered in: Deforestation and the Carbon and Water Cycles
Surface runoff Geography: Water that flows across the ground surface downhill toward rivers instead of soaking into the ground
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Sustainability: Using resources in a way that doesn't harm the environment for future generations
Related: Biome · Climate change · Development · Ecosystem · Environmental geography · Geography
Covered in: What is Geography?
Swash: The movement of water rushing up a beach toward the land when a wave breaks
Related: Backwash · Constructive waves · Destructive waves · Fetch · Tides · Waves
Covered in: Waves and Tides
Symptom: An unusual, persistent change away from your normal appearance, bodily function, or behaviour
Related: Blue Zones · Disease · Health · Mental health · Physical health
Covered in: Good and Ill Health

T

Tectonic plates: Huge, rigid pieces of the Earth's crust and upper mantle (together called the lithosphere) that fit together like a giant jigsaw puzzle and slowly move around on top of the hotter layer below
Related: Biome · Climate change · Crust · Development · Ecosystem · Environmental geography
Covered in: Inside Earth · What is Geography?
Temperate forest: A forest found in mid-latitude regions between the tropics and polar areas, experiencing distinct seasonal changes
Related: Boreal forest · Carbon storage · Habitat · Interception · Tropical rainforest
Covered in: The Forests of the World
Temperate maritime climate: Is a type of climate characterized by moderate temperatures without extreme heat or cold, featuring constant moisture and precipitation occurring throughout the year due to the influence of the surrounding ocean
Related: Air mass · Altitude · Axis tilt · Climate · Climate graph · Latitude
Covered in: The UK's Climate · Weather and Climate
Temperate zone: A mild and damp climate zone located further from the Equator, which is where the United Kingdom sits
Related: Altitude · Climate zone · Equatorial zone · Latitude · Ocean current · Polar zone
Covered in: World Climate Zones
Temperature measurements: Direct records from thermometers, ocean buoys and satellites since 1880, tracked by organisations like the UK Met Office and NASA
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Tertiary consumer: The third consumer in a food chain
Related: Algae · Arrow · Consumer · Food chain · Model · Photosynthesis
Covered in: Food Chains
Tertiary industry: Economic activity that provides services and sells goods rather than manufacturing physical products, such as healthcare, education, retail, and transport
Related: Clark Fisher Model · De-industrialisation · Offshoring · Primary industry · Quaternary industry · Secondary industry
Covered in: Types of Industry
The tropics: The warm area of the world close to the equator
Related: Export · Food miles · Global company · Global supply chain · Globalisation · Greenhouse gases
Covered in: Food Production and Supply Chains
Throughflow: Water flowing slowly through the soil downhill after infiltration
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Tides: The regular, predictable rise and fall of the sea about every 12 hours, caused mainly by the gravitational pull of the Moon
Related: Backwash · Constructive waves · Destructive waves · Fetch · Swash · Waves
Covered in: Waves and Tides
Tissue: A group of similar cells working together to perform a specific job
Related: Adaptation · Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Multicellular organism
Covered in: Multicellular and Unicellular Organisms
Topsoil: The light, nutrient-rich upper layer of soil that plants need to grow
Related: Biomass · Carbon cycle · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis
Covered in: Deforestation and the Carbon and Water Cycles
Tourism: The act of travelling away from home for pleasure or a holiday, which has grown into one of the world's largest global industries focused on the business of providing services, hotels, transport, and attractions for visitors
Related: Beach · Butler's model · Cliff · Coastline · Consolidation stage · Decline stage
Covered in: Introduction to Tourism · The UK Coastline
Town: A settlement bigger than a village, with more shops, several schools, and a wider range of services
Related: City · Global city · Hamlet · Megacity · Natural increase · Rural-to-urban migration
Covered in: The Growth of Cities
Trachea: The windpipe, a tube held open by rings of cartilage that air travels down
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing
Transnational corporations: Large businesses that operate and run stores in many different countries at the same time
Related: Colonisation · Diverse society · Globalisation · Interconnected · Silk Road · World trade
Covered in: Globalisation: An Introduction
Transpiration Biology: The process where plants absorb water through their roots and release it back into the atmosphere through their leaves
Related: Biomass · Carbon cycle · Enhanced greenhouse effect · Food security · Fossil fuels · Photosynthesis
Covered in: Deforestation and the Carbon and Water Cycles
Transpiration Geography: The process of water evaporating specifically from plants and vegetation
Related: Closed system · Condensation · Drainage basin · Evaporation · Groundwater · Groundwater flow
Covered in: The Water Cycle
Tree rings: Rings inside a tree trunk where wide rings show warm, wet years and narrow rings show cold, dry years
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Tributary: A smaller river that flows into a bigger one
Related: Confluence · Drainage basin · Estuary · Mouth · Source · Spring
Covered in: What is a Drainage Basin?
Trilobite: An armoured sea animal of the Paleozoic, related to today's crabs and insects
Related: Anthropocene · Archean · Cenozoic · Eon · Epoch · Era
Covered in: Geological Timescales
Tropic of Cancer: The line of latitude that runs north of the Equator
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Tropic of Capricorn: The line of latitude that runs south of the Equator
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Tropical and desert zone: A hot and bone-dry zone sitting just outside the equatorial belt, home to the world's largest deserts
Related: Altitude · Climate zone · Equatorial zone · Latitude · Ocean current · Polar zone
Covered in: World Climate Zones
Tropical rainforest: A dense forest found between the Tropic of Cancer and the Tropic of Capricorn characterized by year-round heat and heavy rainfall
Related: Boreal forest · Carbon storage · Habitat · Interception · Temperate forest
Covered in: The Forests of the World
Tropics: The region of the Earth between the Tropic of Cancer and the Tropic of Capricorn, either side of the Equator, where it is warm all year
Related: Biome · Canopy · Climate · CLOCC · Condensation · Continent
Covered in: Locational Knowledge of the World · The Tropical Rainforest Biome
Tuberculosis (TB): An infectious disease caused by bacteria, mainly affecting the lungs, treatable with antibiotics
Related: Antibiotics · Disease · Fungicide · Infectious disease · Measles · MMR vaccine
Covered in: Infectious and Non-Infectious Diseases
Type two diabetes: A non-infectious disease where a person's body struggles to control blood sugar levels, linked to lifestyle and obesity
Related: Antibiotics · Disease · Fungicide · Infectious disease · Measles · MMR vaccine
Covered in: Infectious and Non-Infectious Diseases

U

Understory: The dark layer under the canopy, reaching up to about 20 metres
Related: Biome · Canopy · Climate · Condensation · Convectional rainfall · Decomposers
Covered in: The Tropical Rainforest Biome
Unicellular: Made of one single cell
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System
Unicellular organism: A living thing made of a single cell that carries out all seven life processes by itself
Related: Adaptation · Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Multicellular organism
Covered in: Multicellular and Unicellular Organisms
Unsaturated fat: A healthier type of fat, found in foods like avocados and oily fish
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet
Urbanisation: The increase in the proportion of people living in towns and cities compared to rural areas
Related: City · Global city · Hamlet · Megacity · Natural increase · Rural-to-urban migration
Covered in: The Growth of Cities

V

Vacuole: Stores cell sap and keeps the cell firm — found in plant cells, not animal cells
Related: Adaptation · Cell membrane · Cell Wall · Chlorophyll · Chloroplast · Cytoplasm
Covered in: Plant Adaptations for Photosynthesis
Variation: The differences between individuals of the same species, such as petal colour in plants or eye colour in people
Related: Anther · Chromosomes · Cross-pollination · Embryo · Fertilisation · Filament
Covered in: Heredity · Pollination and Fertilisation
Variegated plant: A plant with leaves containing pale or cream patches that have little to no chlorophyll
Related: Adaptation · Cell membrane · Cell Wall · Chlorophyll · Chloroplast · Cytoplasm
Covered in: Plant Adaptations for Photosynthesis
Vertebrate: An animal that has a backbone
Related: Behavioural Differences · Binomial Name · Carnivore · Class · Classification · Deciduous
Covered in: Classification and Species
Village: A settlement of a few hundred people, typically with one small shop and a primary school
Related: City · Global city · Hamlet · Megacity · Natural increase · Rural-to-urban migration
Covered in: The Growth of Cities
Villi: Are millions of microscopic, finger-like folds or bumps lining the inside walls of the small intestine that act to massively increase and maximize the surface area available for nutrient absorption into the blood
Related: Absorption · Amino acids · Anus · Bile · Circulatory system · Concentration gradient
Covered in: Absorption and Transport of Nutrients · The Human Digestive System
Vision 2030: Saudi Arabia's national strategy launched in 2016 aimed at economic diversification, major projects, and social reforms
Related: Distribution · Economic diversification · Economy · Export · Import · Natural resource
Covered in: Natural Resources and the Economy in the Middle East
Visitor economy: The overall financial boost and job creation driven by money spent by tourists in a local area
Related: Beach · Cliff · Coastline · Fishing industry · Shingle · Tourism
Covered in: The UK Coastline
Vitamin C: Keeps cells healthy and helps wounds heal
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet
Vitamin D: Keeps bones and teeth strong and supports a healthy immune system
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet
Vitamin K: A vitamin produced by gut bacteria that your body needs but cannot make
Related: C. difficile · Cell Wall · Competition · Cytoplasm · Digestion · DNA
Covered in: Bacteria in the Digestive System
Volcanic eruptions: A natural cause of climate change where volcanoes release ash that blocks sunlight and carbon dioxide that traps heat
Related: Adaptation · Climate change · Deforestation · Enhanced greenhouse effect · Fossil fuels · Glacials
Covered in: Climate Change
Volume: The amount of space inside something, such as the chest or a box
Related: Alveoli · Bell jar model · Bronchi · Bronchioles · Bronchus · Circulatory system
Covered in: The Human Gas Exchange System and Breathing

W

Water: Needed for chemical reactions in the body and to stay hydrated
Related: Balanced diet · Calcium · Carbohydrates · Eatwell Guide · Fibre · Food group
Covered in: Balanced Diet
Water vapour: One of the three greenhouse gases, along with carbon dioxide and methane
Related: Atmosphere · Carbon Dioxide · Emissions · Enhanced greenhouse effect · Fossil fuels · Greenhouse effect
Covered in: The Greenhouse Effect
Watershed: The ridge of high ground that forms the boundary between one drainage basin and the next, where rain on each side flows into a different river system
Related: Confluence · Drainage basin · Estuary · Mouth · Source · Spring
Covered in: What is a Drainage Basin?
Wave-cut notch: A hollow cut into the base of a cliff by erosion concentrated between high and low tide
Related: Abrasion · Arch · Attrition · Cave · Coastal erosion · Hydraulic action
Covered in: Coastal Erosion
Wave-cut platform: A flat rocky ledge left behind at the base of a retreating cliff as it collapses and moves backwards
Related: Abrasion · Arch · Attrition · Cave · Coastal erosion · Hydraulic action
Covered in: Coastal Erosion
Waves: The movement of energy across water driven by wind blowing across the surface of the sea or ocean
Related: Backwash · Constructive waves · Destructive waves · Fetch · Swash · Tides
Covered in: Waves and Tides
Weather: The short-term, day-to-day condition of the atmosphere (such as whether it is sunny, rainy, or windy) that can change from hour to hour
Related: Axis tilt · Climate · Climate graph · Northern Hemisphere · Precipitation · Southern Hemisphere
Covered in: Weather and Climate
White blood cells: Cells carried in the plasma that fight infection
Related: Absorption · Amino acids · Circulatory system · Concentration gradient · Diffusion · Digestion
Covered in: Absorption and Transport of Nutrients
World trade: The global exchange of goods and services across national borders
Related: Colonisation · Diverse society · Globalisation · Interconnected · Silk Road · Transnational corporations
Covered in: Globalisation: An Introduction

X

Xylem: Specialized transport cells that form continuous hollow tubes composed of dead cells with thick walls to carry water upward from roots to leaves
Related: Cell membrane · Cell Wall · Chloroplast · Cytoplasm · Mitochondria · Nucleus
Covered in: Plant Cell Structures and Their Functions

Z

Zygote: The first cell of a new organism, made when the nuclei of a male gamete and a female gamete fuse together, with a full set of chromosomes
Related: Adult stem cells · Anther · Bone marrow · Chromosomes · Cross-pollination · Differentiation
Covered in: Pollination and Fertilisation · Stem Cells in Animals