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neurologyYou need to know

• An ecosystem is a community of living organisms interacting with the non-living conditions of their environment.
• The living parts of an ecosystem are its biotic components and the non-living parts are its abiotic components.
• Abiotic factors are the non-living parts of an ecosystem, including sunlight, water, temperature and soil.
• Biotic factors are the living components of an ecosystem, including plants, animals, fungi and bacteria.
• Ecosystems exist at different scales, from a small pond to a global biome.
• A biome is a large-scale global ecosystem made up of places with similar climate, vegetation and wildlife.
• Biodiversity is the variety of plant and animal species in an ecosystem.
• The level of biodiversity in an ecosystem depends on climate, available habitats and food sources.
• Interdependence means that organisms in an ecosystem depend on each other and on abiotic resources such as water, shelter and nutrients.
• A change in one part of an ecosystem can produce significant knock-on effects elsewhere in the ecosystem.
• Feeding relationships between organisms can be shown by food chains and food webs.
• Producers begin food chains because they make biomass from sunlight, usually by photosynthesis.
• A consumer is an organism that gets its energy by eating other organisms.
• Primary consumers feed on producers and are herbivores or omnivores.
• Secondary consumers feed on primary consumers and are carnivores or omnivores.
• Tertiary consumers feed on secondary consumers and are carnivores or omnivores.
• Decomposers such as bacteria and fungi break down dead organic matter and waste.
• Decomposers return nutrients to the soil and release energy so matter can be recycled within the ecosystem.
• A food chain shows the transfer of energy from one organism to the next.
• The original source of energy for most food chains is sunlight.
• A food web shows the many connected feeding relationships within an ecosystem.
• If one species declines in a food web, the populations of its food source and its predators are also likely to change.
• A deciduous woodland is a small-scale UK ecosystem that contains a wide variety of habitats for plants, insects and animals.
• Producers in a deciduous woodland include trees such as oak, beech, elm and ash and ground plants such as holly, ferns, bluebells and wild garlic.
• Primary consumers in a deciduous woodland include insects, rabbits, deer and squirrels.
• Secondary consumers in a deciduous woodland include frogs, voles, foxes and badgers.
• Tertiary consumers in a deciduous woodland include foxes and birds of prey such as kestrels.
• Some animals occupy more than one trophic level because their diet includes organisms from different levels in the food web.
• Decomposers are vital to the nutrient cycle in deciduous woodland ecosystems.
• The biotic and abiotic components of deciduous woodland are linked through food webs and nutrient cycling.
• Rowan trees depend on birds to disperse their seeds to new locations.
• Oak trees can regenerate when squirrels bury acorns for storage and fail to recover them.
• Deciduous trees shed their leaves each year, creating leaf litter that decomposes and adds nutrients to the soil.
• In spring, woodland flowers such as bluebells and daffodils can grow rapidly before the tree canopy blocks much of the sunlight.
• Ash dieback disrupts deciduous woodland ecosystems because more than 1,000 species depend on ash trees.
• The loss of ash trees can reduce populations of insects, birds and small mammals and then affect the predators that feed on them.
• A stable ecosystem is one in which biotic and abiotic components remain in balance and populations stay fairly constant over time.
• Stable ecosystems can take hundreds of years to develop but can be disturbed very quickly.
• Ecosystem balance can be disrupted by natural events such as wildfire, disease, invasive species and extreme weather.
• Ecosystem balance can also be disrupted by human activities such as deforestation, hunting, hedgerow removal, altered drainage, chemical use and deliberate burning.
• Invasive grey squirrels can reduce red squirrel populations by competing for food and space and by spreading squirrel pox.
• Earths biosphere contains 11 major biomes.
• The global distribution of biomes is influenced by latitude, precipitation, altitude, continentality and ocean currents.
• Temperature and sunshine generally decrease with increasing distance from the equator.
• Areas of high pressure tend to have low rainfall, while areas of low pressure tend to have higher rainfall.
• Temperature falls as altitude increases.
• Inland locations usually heat up more quickly in summer and cool down more quickly in winter than coastal locations. Warm and cold ocean currents can raise or lower temperatures on nearby land.
• Tropical rainforests are found at low latitudes near the equator in South America, Asia and Africa.
• Tropical rainforests have year-round high temperatures, convectional rainfall of about 2,000 mm a year, very high biodiversity and distinct layers of vegetation.
• Mediterranean biomes are found around 40° to 45° north of the equator in places such as southern Europe and North Africa.
• Mediterranean biomes have hot dry summers, mild wet winters, dense scrubland and plants such as lavender, rosemary, citrus and olives.
• Deciduous forests are found around 50° north of the equator in Europe and North America.
• Deciduous forests have mild wet winters, warm drier summers and trees that lose their leaves in winter.
• Coniferous forests are found around 60° north of the equator in northern Europe, Canada and Russia.
• Coniferous forests have cold winters, mild summers, many evergreen trees such as spruce and pine and lower biodiversity than temperate deciduous forests.
• Savanna grasslands are found between about 15° and 30° north and south of the equator in South America, central Africa and Australia.
• Savanna grasslands have distinct wet and dry seasons, temperatures of about 15°C to 35°C, annual rainfall of about 800 to 900 mm, dominant grasses and scattered trees such as baobab and acacia.
• Temperate grasslands are found between about 30° and 40° north and south of the equator in regions such as southern Africa, Russia and North America.
• Temperate grasslands have hot summers, very cold winters, annual rainfall of about 250 to 750 mm, many grasses and very few trees.
• Deserts are found around 20° to 30° north and south of the equator in Africa, Australia and North and South America.
• Deserts have very low rainfall, hot daytime temperatures, cold nights, low biodiversity and plants such as cacti and yucca.
• Polar and tundra biomes are found above about 60° north and south of the equator in the Arctic, Antarctic, northern Canada and Siberia.
• Polar and tundra biomes have temperatures below 0°C for much of the year, precipitation often below 250 mm, short growing seasons, low biodiversity and vegetation dominated by small grasses, lichens and mosses.
• High biodiversity is often found where high temperatures and high rainfall allow plants to grow rapidly throughout the year.
• Avington Park Lake in Hampshire is a named example of a small-scale UK freshwater pond ecosystem.
• The bottom of Avington Park Lake has very little light and oxygen, so decomposers and scavengers such as water worms and rat-tailed maggots feed on dead material there.
• Mid-water in Avington Park Lake is dominated by fish as the main predators, while organisms such as water fleas and dragonfly nymphs feed within the water column and breathe through gills or their skin.
• The surface waters of Avington Park Lake have plentiful light and oxygen and support animals such as ducks, water boatmen, midge larvae and tadpoles.
• The pond margin at Avington Park Lake has high light and oxygen levels, allowing plants such as marsh marigold to thrive and provide sheltered habitats for insects and amphibians such as frogs.
• The space above Avington Park Lake supports mobile species such as kingfishers and dragonflies.
• Natural factors that can change the Avington Park Lake ecosystem include drought, flood, fire and disease.
• Human management can alter the Avington Park Lake ecosystem by stocking more fish, changing land drainage, changing water pH or increasing nutrient levels through fertiliser leaching.
• Fertiliser leaching can cause eutrophication in Avington Park Lake, which means the water becomes excessively rich in nutrients.
• Without maintenance, Avington Park Lake accumulated silt and vegetation, which created an excellent habitat for birds but blocked the view of the lake from the house.
• Restoration work in 2014 aimed to restore Avington Park Lake and preserve its function as a bird habitat.
• Desilting and reshaping Avington Park Lake created new waterside habitats that attracted nesting birds and waterfowl.
• After restoration, Avington Park Lake became visible again from the house and functioned as a healthier ecosystem supporting a diverse range of wildlife.
• Ash dieback is a tree disease affecting UK woodlands that can disrupt food webs.
• Tropical rainforest ecosystems have distinctive physical characteristics.
• Tropical rainforest ecosystems are shaped by the interdependence of climate, water, soils, plants, animals and people.
• Plants and animals in tropical rainforests are adapted to the physical conditions of the ecosystem.
• Tropical rainforest ecosystems raise important issues related to biodiversity.
• Deforestation in tropical rainforests has both economic and environmental impacts.
• Tropical rainforests need sustainable management because they are valuable to people and the environment.
• Strategies for sustainable management of tropical rainforests include selective logging and replanting, conservation and education, ecotourism, international agreements about tropical hardwoods and debt reduction.
• Tropical rainforests are found mainly between 15° north and 15° south of the Equator in the equatorial climate zone.
• Tropical rainforests cover about 6% of the Earth's surface, and the largest remaining tropical rainforest is the Amazon Basin.
• Major tropical rainforest regions include the Amazon Basin, Central America, Central Africa and South-East Asia.
• Tropical rainforests receive more than 2000 mm of precipitation each year.
• Mean monthly temperatures in tropical rainforests stay high at about 26-28°C throughout the year.
• Tropical rainforests have a small annual temperature range and a diurnal temperature range of about 7°C.
• Tropical rainforests are hot and wet all year, so they do not have distinct seasons.
• Humidity in tropical rainforests is usually above 75-80%.
• Many tropical rainforest soils are latosols.
• Tropical rainforest soils are generally infertile because heavy rainfall causes leaching and plants rapidly absorb available nutrients.
• Most nutrients in tropical rainforest soils are concentrated in the thin upper layer of topsoil.
• Tropical rainforests have the greatest biodiversity of any terrestrial biome and may contain more than half of the world's plant and animal species.
• Traditional communities such as the Awa in Brazil have used tropical rainforest resources sustainably through hunting and gathering.
• Commercial activities such as mining, agriculture and logging have forced many indigenous rainforest communities off their land.
• Tropical rainforest ecosystems are interdependent, so a change in climate, water, soils, plants, animals or people affects the other components.
• Deforestation reduces habitats, lowers biodiversity and disrupts the tropical rainforest nutrient cycle.
• High rainfall and year-round heat create a continuous growing season in tropical rainforests.
• Nutrient cycling in tropical rainforests is rapid because fallen plant material decomposes quickly in warm, wet conditions.
• Plants in tropical rainforests take up nutrients quickly, so most nutrients are stored in living biomass rather than in soil or litter.
• Rapid nutrient cycling does not make tropical rainforest soils fertile because nutrients are removed from the soil almost as soon as they are released.
• Tropical rainforests have five main vegetation layers: the ground layer, the shrub layer, the under-canopy, the canopy and the emergent layer.
• In tropical rainforests, the shrub layer is about 3-4 metres high, the under-canopy about 15 metres high, the canopy about 30 metres high, and emergent trees about 45-55 metres high.
• Waxy leaves with drip tips help tropical rainforest plants shed water quickly, which reduces mould growth and leaf damage.
• Buttress roots support very tall tropical rainforest trees because much of the root system is shallow.
• Lianas climb tropical rainforest trees to reach sunlight above the forest floor.
• Epiphytes grow on tree trunks and branches and obtain nutrients from the air, rain and trapped debris.
• Straight, smooth trunks reduce the number of epiphytes that can attach to a tropical rainforest tree.
• Camouflage is a common tropical rainforest adaptation, as shown by sloths with algae in their fur and stick insects that resemble twigs or leaves.
• Many tropical rainforest animals are adapted for feeding or movement in trees, such as toucans with large bills, primates with prehensile tails and geckos with adhesive toe pads.
• High rainfall, constant warmth, rapid nutrient cycling and varied plant life create many habitats and support very high biodiversity in tropical rainforests.
• Human threats to tropical rainforest biodiversity include slash-and-burn agriculture, mining, hydroelectric power development, logging, road building, settlements and increasingly severe wildfires.
• Because tropical rainforest food webs are interdependent, the decline of one species can trigger declines in many others, especially when a keystone species is affected.
• Biodiversity loss in tropical rainforests can cause extinction, remove potential medicinal resources and undermine indigenous ways of life.
• Deforestation is the felling and clearance of trees.
• Brazil, the Democratic Republic of the Congo, Bolivia and Indonesia experience some of the highest levels of deforestation in the world.
• Rates of tropical deforestation increased steadily from 2001 to 2016 and have decreased slightly since 2016.
• Deforestation in tropical rainforests is usually caused by several linked human activities rather than by a single factor.
• Major human causes of tropical rainforest deforestation include logging, road building, mineral extraction, energy development, settlement growth, subsistence farming and commercial farming.
• Wildfires are a natural cause of deforestation, and the frequency and severity of tropical rainforest wildfires have increased because of human-induced climate change.
• Commercial farming can cause deforestation when rainforest is cleared for monoculture plantations such as oil palm.
• Subsistence farming can cause deforestation through slash-and-burn clearance, and these fires can spread beyond the intended area.
• Logging causes deforestation directly and also leads to further forest loss when roads and settlements are built to support timber extraction.
• Road building contributes to deforestation directly and also opens previously inaccessible rainforest to further farming, logging and mining.
• Mineral extraction causes deforestation for mines, drilling sites and the transport infrastructure needed to reach them.
• Energy development causes deforestation when large hydroelectric schemes flood extensive areas of rainforest.
• Settlement growth causes deforestation because land is cleared for homes, services and the agriculture needed to support a larger population.
• Deforestation often replaces diverse tropical rainforest ecosystems with monocultures, which reduces biodiversity.
• Deforestation reduces interception and infiltration, so less water returns to the atmosphere through evapotranspiration and precipitation can decline.
• Reduced interception and infiltration increase overland flow, which raises the risk of soil erosion and river sedimentation.
• Deforestation increases nutrient leaching because fewer trees intercept rainfall and protect the soil.
• Tropical rainforest soils become less fertile and drier after deforestation, and heavily weathered soils may become reddish brown because iron oxides are more visible.
• Most nutrients in a tropical rainforest are stored in living biomass, so clearing trees removes the main nutrient store in the ecosystem.
• Deforestation raises atmospheric carbon dioxide concentrations because fewer trees absorb carbon dioxide and clearance fires release additional emissions.
• Deforestation contributes to the enhanced greenhouse effect and to human-induced climate change.
• Deforestation can improve quality of life for some people by creating jobs and increasing incomes.
• Deforestation can increase employment in mining, forestry, agriculture and hydroelectric power.
• Deforestation can increase national income through exports such as minerals, timber and crops.
• Deforestation reduces the land available to indigenous communities, weakens traditional ways of life and can lead to losses of culture and traditions.
• Deforestation can reduce food supplies for indigenous communities and increase the risks of landslides and flooding to settlements.
• Deforestation also reduces potential future medicines by destroying species before they are studied.
• Brazil has experienced very rapid deforestation, with more than 140,000 hectares of rainforest cleared on average each year since 2000.
• The Amazon Rainforest is the largest tropical rainforest on Earth and lies within the Amazon River basin.
• The Amazon Rainforest covers about 40% of South America and extends across Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana and Suriname.
• Logging for valuable hardwoods such as mahogany and teak causes deforestation in the Amazon and accounts for about 10% of rainforest loss there.
• Mineral extraction, including iron and copper mining, is a cause of Amazon deforestation, and by 2016 mining used about 50,000 hectares of land.
• Population pressure contributes to Amazon deforestation because many people migrate into the rainforest in search of work, and the population grew by 23% between 2000 and 2010.
• Commercial farming is the leading cause of deforestation in the Brazilian Amazon because rainforest is cleared to create cattle ranches.
• Subsistence farming has a more limited impact on the Amazon because it is usually small-scale and mainly supports local communities.
• Deforestation in the Amazon can create jobs by opening land for mining, farming and energy development.
• Economic activity in the Amazon can increase government tax revenues, which can be used to improve public services such as education.
• New transport infrastructure in the Amazon can encourage further industrial development and tourism. One new road network was the Trans Amazonian Highway.
• Brazil earned $6.9 billion from cattle trading in 2010, showing the economic importance of ranching linked to Amazon deforestation.
• Deforestation in the Amazon may drive plant species with possible medicinal value to extinction before they are studied.
• Deforestation in the Amazon reduces biodiversity by destroying habitats, and about 137 plant and animal species are estimated to be lost each day.
• Continued deforestation in the Amazon could reduce the number of species in the rainforest by 30-45% by 2030.
• Removing rainforest vegetation in the Amazon exposes soil to heavy rainfall, which increases soil erosion.
• Soil erosion linked to Amazon deforestation causes about 55 million tonnes of soil to be lost each year.
• Deforestation in the Amazon contributes to climate change because fewer trees are left to absorb carbon dioxide.
• Debt reduction can support sustainable management of the Amazon when richer countries cancel debt in return for rainforest protection.
• In 2010, the United States and Brazil converted $21 million of Brazilian debt into a fund to protect tropical ecosystems.
• International agreements can reduce Amazon deforestation by restricting imports of timber that is not from sustainable sources.
• The Forest Stewardship Council promotes sustainable forestry by certifying timber that has been sourced responsibly.
• Selective logging can reduce environmental damage in the Amazon because only trees that have reached a required size are felled.
• Education can support sustainable management of the Amazon by helping people understand the consequences of deforestation.
• In Brazil, the Coffee Sustainability Curriculum has been delivered through an app and advanced training courses to encourage more sustainable practice.
• Tropical rainforests need sustainable management because rapid deforestation threatens ecosystems and long-term resource use.
• Tropical rainforests can be managed through strategies at international, national and local scales.
• The UN Forum on Forests was established in 2000 to promote the management, conservation and sustainable development of all types of forest.
• The UN Sustainable Development Goals include the sustainable management of forests.
• International protection can limit damage to tropical rainforests by restricting activities such as hunting, logging, fishing and access in protected areas.
• The Convention on International Trade in Endangered Species of Wild Fauna and Flora aims to ensure that international trade in wild plants and animals does not threaten species survival.
• The International Tropical Timber Agreement promotes sustainable forest management and restricts trade in unsustainably sourced tropical hardwood.
• The Forest Stewardship Council certifies timber from sustainable sources.
• Debt reduction can protect tropical rainforests when part of a country's debt is cancelled in return for conservation.
• International organisations such as Greenpeace and WWF monitor deforestation.
• Brazil's forest code requires landowners to keep a proportion of their land under forest.
• In Brazil, the required proportion of land kept as forest was reduced from 80% to 50% in 2012.
• Brazil launched the DETER satellite in 2004 to detect deforestation and send reports to rangers.
• By 2011, the DETER satellite was sending daily reports that helped patrols target suspicious activity.
• The DETER satellite cannot detect areas smaller than 250 square metres, so some people reduce the size of the area they clear to avoid detection.
• In some areas, the DETER satellite system contributed to a 60% decrease in large-scale deforestation.
• Brazil's national parks protect rainforest ecosystems by conserving large areas.
• Reforestation projects help restore rainforest by planting trees on cleared land.
• The Amazonia Sustainable Landscapes Project aimed to restore 30,000 hectares of forest by 2023 by planting 73 million trees.
• The Amazon Region Protected Areas programme increased protected areas and Indigenous territories by 68% between 2004 and 2012.
• Selective logging reduces damage to tropical rainforests because only chosen trees are felled and removed carefully.
• Afforestation replaces trees that have been felled by planting new trees.
• Agroforestry combines agriculture with forestry so that some trees remain on the land.
• Agroforestry can reduce deforestation, provide shade, increase infiltration and interception, reduce soil erosion, add organic matter and nutrients to the soil, and increase biodiversity.
• Education can support sustainable rainforest management by helping people involved in exploitation and management to use more sustainable practices.
• Ecotourism is designed to focus on the natural environment while having a low impact on tropical rainforests.
• Sustainable ecotourism uses local materials and designs buildings to blend into the environment.
• Ecotourism can support local communities by using locally grown food and employing local people.
• Ecotourism can educate visitors about the rainforest and generate income that can be used for conservation.
• Ecotourism gives local communities a financial incentive to protect the rainforest instead of clearing it.
• Abiotic factors in a tropical rainforest ecosystem are the non-living components, such as sunlight, water, temperature and soil.
• Biotic factors in a tropical rainforest ecosystem are the living components, such as plants, animals, fungi and bacteria.
• Buttress roots are large above-ground roots that support tall tropical rainforest trees growing in shallow soil.
• The canopy is the upper layer of the tropical rainforest formed by closely packed tree crowns, usually about 30 to 45 metres above the ground.
• Drip tips are leaf adaptations that allow rainwater to run off quickly and so reduce mould growth.
• Emergent trees are the tallest trees in a tropical rainforest and rise above the canopy to about 50 to 55 metres.
• Epiphytes are plants that grow on tree trunks and branches to reach sunlight and absorb nutrients from the air and rain.
• Interdependence in a tropical rainforest means that plants, animals, climate and soils depend on one another for survival.
• Lianas are woody vines that climb tropical rainforest trees to reach sunlight in the canopy.
• The nutrient cycle in a tropical rainforest is the continuous transfer of nutrients through biomass, litter and soil, driven by rapid decomposition.
• Photosynthesis is the process by which green plants make food using sunlight, carbon dioxide and water.
• The shrub layer is the lowest vegetation layer in a tropical rainforest and is made up of small plants and young trees, usually below about 3 to 4 metres.
• Species biodiversity is the variety of plant and animal species in an ecosystem, and tropical rainforests have some of the highest species biodiversity on Earth.
• The under-canopy is the tropical rainforest layer below the canopy where young trees and shrubs grow in limited light.
• Waxy leaves are a tropical rainforest plant adaptation that repels water and helps prevent mould and leaf damage.
• The water cycle is the continuous movement of water through evaporation, condensation, precipitation and runoff, and tropical rainforest vegetation strongly influences this cycle.
• Stick insects are tropical rainforest animals that resemble twigs or leaves, which helps them avoid predators through camouflage.
• Clear felling is the complete removal of trees from an area and often causes severe environmental damage.
• Deforestation is the cutting down and removal of forest cover, often to make space for farming, mining or settlement.
• Illegal logging is the unauthorised cutting down of trees in breach of environmental laws or protection rules.
• Logging is the cutting down of trees for timber, and unsustainable logging can lead to large-scale deforestation.
• Palm oil is a widely used oil produced from oil palm trees, and rainforest is often cleared to establish palm oil plantations.
• Tropical hardwoods are dense and valuable woods, such as teak and mahogany, that are commonly used for furniture and construction.
• A carbon sink is an area such as a tropical rainforest that absorbs more carbon dioxide than it releases.
• Hydroelectric power is energy generated from flowing water, and hydroelectric schemes may require tropical rainforest land to be flooded for dams.
• Minerals are natural resources such as tin, iron ore and gold that may be extracted from tropical rainforest regions.
• Slash and burn is a method of clearing forest by cutting and burning vegetation, often for subsistence farming.
• Soil erosion is the wearing away of soil by wind or rain, and it becomes more severe when tropical rainforest roots no longer bind the soil.
• Afforestation is the planting of trees in areas that have not recently been covered by forest.
• Agroforestry is a land-use system that combines trees with crops and can improve biodiversity and soil fertility while reducing deforestation.
• A debt-for-nature swap is an agreement in which part of a country's debt is cancelled in return for commitments to protect the environment.
• Ecotourism is tourism focused on natural environments that aims to minimise environmental damage and benefit local communities.
• The Forest Stewardship Council is an organisation that certifies timber from sustainably managed forests.
• The International Tropical Timber Agreement is an international agreement that promotes sustainable forest management and limits trade in unsustainably sourced tropical timber.
• Reforestation is the replanting of trees in areas where forest has been lost.
• Selective logging is the careful removal of chosen trees in order to minimise damage to the surrounding forest.
• Sustainable management of a tropical rainforest means using rainforest resources in ways that meet present needs without damaging the ecosystem for future generations.
• The UN Forum on Forests is an international body that supports the conservation and sustainable development of forests.
• The UN Sustainable Development Goals are a set of goals adopted by the United Nations in 2015 to end poverty and protect the planet, including through sustainable forest management.
• The two main types of cold environment are polar environments and tundra environments.
• Polar environments include Antarctica and Arctic areas such as Greenland, northern Russia and northern Canada.
• Tundra environments are characterised by permafrost and short summers, and they occur mainly around the edge of the Arctic Ocean in North America and Eurasia and around Greenland.
• Small tundra areas also occur in South Georgia and the Antarctic Peninsula because the Southern Hemisphere has little land at high latitudes.
• Cold environments are fragile ecosystems that are easily damaged because harsh conditions limit biodiversity and slow recovery.
• At very high latitudes, the Sun may not rise or set for several months of the year.
• Tundra winter temperatures can fall to about -50°C, while summer temperatures can reach about 10°C.
• Tundra climates have low precipitation, usually below 380 mm per year, and clearly defined seasons with permanent darkness in winter and continuous daylight in summer.
• Tundra soils are thin, acidic and infertile above a layer of permafrost that can extend hundreds of metres below the surface.
• Tundra permafrost stores large quantities of methane, which is a greenhouse gas.
• The tundra growing season is short, so plants grow slowly, stay low to the ground and are mainly grasses, mosses and lichens.
• Trees do not usually grow in tundra permafrost, although small trees can survive in warmer sheltered locations.
• Many tundra flowering plants have short life cycles and bright flowers to attract insects quickly during the brief summer.
• Tundra animal diversity is low but greater than in polar regions, and common species include polar bears, wolves, caribou, Arctic foxes, hares and snow geese.
• About four million people live in tundra regions, including many Indigenous communities and workers in oil and gas settlements.
• Polar regions lie within the Arctic and Antarctic Circles, from about 66.5° to 90° north and south.
• Polar regions are the coldest places on Earth, with winter temperatures often below -40°C and annual precipitation usually below 100 mm.
• Polar regions have long, cold, windy winters, permanently frozen icecaps and little or no soil because ice sheets cover most of the land.
• Plant life in polar regions is extremely limited, although lichens, mosses and a few grasses can survive on exposed rocks or milder coasts.
• Animal diversity in polar regions is very low, with penguins in Antarctica and polar bears in the Arctic, alongside species such as whales, seals, walruses and snowy owls.
• Antarctica is almost uninhabited apart from seasonal scientific research, while some Arctic regions support Indigenous populations.
• Climate, permafrost, soils, plants, animals and people in cold environments are interdependent, so a change in one part of the system affects the others.
• Rising temperatures increase summer sea-ice melt, which threatens seals and polar bears that depend on sea ice for breeding and hunting.
• Sparse plant cover and low temperatures cause slow plant growth and slow decomposition, which leaves cold-environment soils nutrient-poor.
• Herbivores such as reindeer depend on tundra plants for food, while their dung and seed dispersal help maintain soil fertility and plant reproduction.
• Carnivores such as wolves depend on herbivores and follow them to areas where vegetation is available.
• In summer, tundra vegetation helps protect permafrost by limiting thawing of the ground beneath the surface.
• Permafrost supplies plants with water and nutrients, but when permafrost is damaged and melts it can cause flooding, stop plant growth and release methane that increases global warming.
• Tundra plants must survive boggy, waterlogged summers and frozen, dark winters.
• Some cold-environment animals hibernate to conserve energy during winter, and Arctic ground squirrels can hibernate for seven to eight months.
• Insulation such as thick fur and blubber reduces heat loss and lowers the amount of energy animals need to stay warm.
• Many birds migrate away from cold environments in winter, and Arctic terns move between the Arctic summer and the Antarctic summer.
• White winter coats provide camouflage in snow, helping predators approach prey and helping prey avoid detection.
• Many cold-environment animals have compact bodies, short limbs, thick fur or blubber and large tough feet or hooves that reduce heat loss and help movement on snow and ice.
• Many plants become dormant in winter to survive prolonged cold and darkness.
• Tundra plants are usually small and rounded to reduce exposure to strong winds.
• Tundra plants have shallow roots because permafrost prevents deep root growth.
• Tundra leaves are usually small to reduce moisture loss.
• Many cold-environment plants reproduce through runners or bulbs rather than seeds because the growing season is only about 50 to 60 days long.
• Cold environments have very low biodiversity, especially in Antarctica, so food webs are easily disrupted if one species declines.
• Species adapted to cold environments may face extinction as global warming shifts suitable habitats and leaves specialist species with nowhere colder to move.
• Development of cold environments creates economic opportunities through mineral extraction, energy production, fishing and tourism, but exploiting these resources also increases environmental risk.
• Cold environments contain valuable mineral reserves such as gold, silver, iron ore and copper, and some countries are expanding mining beneath the tundra.
• Cold environments contain abundant oil and gas reserves.
• Deep, cold water supports species that can command high prices on global markets.
• Overfishing can deplete fish stocks in cold environments.
• Tourism in cold environments has grown.
• Adventure tourism in extreme cold environments provides income for national and local economies.
• Rugged, mountainous relief makes many cold environments inaccessible and difficult for vehicles to reach.
• Very low temperatures and long periods of darkness make construction difficult in cold environments.
• Building roads, railways, pipelines and utility networks is difficult on frozen ground that may thaw.
• Pipelines in permafrost areas often cannot be buried and must be designed to withstand freezing conditions.
• If permafrost melts, the ground can become unstable and landslides can occur.
• Frozen, unstable ground makes it difficult to create strong foundations for buildings.
• The Trans-Alaska Pipeline System is about 800 miles long and was built to move oil across Alaska because Arctic sea ice limits winter shipping.
• Parts of the Trans-Alaska Pipeline are raised on stilts to stop the pipeline from melting permafrost and destabilising the ground.
• Houses in permafrost areas are raised on stilts so heat from the buildings does not melt the frozen ground below.
• Svalbard is a Norwegian territory in the Arctic Ocean and is the world's most northerly permanently inhabited group of islands.
• Svalbard has a polar climate, with about 60% of the land covered by glaciers and most of the remaining land covered by tundra.
• Svalbard is too cold for farming or tree growth.
• Svalbard has a population of about 2,700 people, and most residents live in Longyearbyen.
• Coal mining has been a major economic activity in Svalbard, employing about 300 people in mines and support services.
• Falling coal prices have caused Svalbard's coal industry to decline and have led to job losses.
• Svalbard's coal-fired power station provides the community's energy and is Norway's only coal-fired power station.
• Some environmentalists argue that Svalbard should replace coal power with renewable energy, including geothermal energy, because the islands lie close to the Mid-Atlantic Ridge.
• One proposed way to reduce emissions in Svalbard is to capture carbon dioxide from burning coal and use it in electricity generation.
• The Barents Sea near Svalbard is one of the richest fishing grounds in the world and contains more than 150 fish species, including cod.
• Fishing around Svalbard is managed jointly by Norway and Russia to keep fish stocks sustainable.
• Tourism provides about 300 jobs in Svalbard.
• About 70,000 tourists visited Svalbard in 2011, including about 30,000 cruise-ship passengers.
• Svalbard attracts tourists with glaciers, fjords, wildlife, adventure activities and winter views of the Northern Lights.
• Winter temperatures in Svalbard can fall below -30°C, and limited daylight makes living and working difficult.
• Most construction work in Svalbard is carried out during the short summer.
• In Svalbard, water, electricity and sewage pipes are kept above the ground so that heat from the pipes does not thaw the permafrost and so they remain accessible for maintenance.
• Roads in Svalbard are made of gravel and raised above the ground surface to reduce damage from permafrost thaw.
• Svalbard is difficult to access because there are only about 50 km of roads in Longyearbyen and most local travel is by snowmobile.
• Svalbard's remote location means transport depends on air links, including one main airport with international connections.
• Cold environments are valued as wilderness areas because they remain largely natural, undisturbed, undeveloped and often uninhabited.
• Wilderness areas in cold environments provide niche habitats that help to protect biodiversity.
• Wilderness areas in cold environments allow scientists to study plants and animals in their natural habitats.
• Comparing natural ecosystems in cold environments with managed ecosystems helps scientists to understand environmental processes and human impact.
• Cold environments contain some of the last extensive areas on Earth that remain largely unchanged by human activity.
• Cold environments are fragile environments because damage occurs easily and recovery is slow.
• Climate change is one of the main threats to cold environments.
• Plant growth in cold environments is very slow, so vegetation damaged by vehicles or other human activity may take a very long time to recover or may not recover at all.
• Many species in cold environments are highly specialised, so additional environmental change can make adaptation difficult.
• Polar bears are adapted to hunt on sea ice, and earlier melting of sea ice is contributing to declining polar bear numbers.
• Pollution can cause severe environmental damage in cold environments, and oil spills have caused major ecological disasters.
• Economic development can degrade land in cold environments by melting permafrost, including where buildings warm the ground.
• Sustainable management in cold environments aims to prevent environmental damage, allow recovery from use and ensure that local people benefit from the environment.
• Sustainable management in cold environments can include using geothermal energy, creating conservation zones, promoting native cultures, reducing pollution, encouraging ecotourism and using appropriate technology.
• The 1998 Protocol on Environmental Protection to the Antarctic Treaty requires environmental impact assessment before new activities are allowed in Antarctica.
• Antarctic protection measures include restricting cruise ships to no more than 500 passengers, limiting visitor numbers to 100 or fewer at a site and banning military and nuclear activities.
• Climate change is damaging the Arctic, and polar bears were added to the Endangered Species List in 2008.
• Governments need to regulate development in cold environments because activities such as mining, energy extraction and logging can cause pollution and destroy habitats.
• Legal protection can limit future development in cold environments, as shown by the 1964 Wilderness Act and other protected areas in Alaska.
• Government investment in environmental science can help to protect marine habitats, fisheries and the sustainability of economic activity in cold environments.
• Conservation groups cannot regulate development directly, but they can pressure governments to protect cold environments that are threatened or damaged.
• Conservation groups such as Greenpeace and WWF promote sustainable management and campaign against activities that would damage cold environments.
• Conservation groups collect independent data, monitor the reliability of other evidence, lobby for change and publish findings to increase public awareness.
• The active layer is the top layer of soil in tundra regions that thaws during the short summer above permanently frozen permafrost.
• Biodiversity is the variety of species living in a habitat, and biodiversity is generally low in cold environments.
• Carnivores are meat-eating animals such as wolves and polar bears that depend on herbivores or fish as prey in cold environments.
• Cold environments are regions where temperatures remain below freezing for much of the year, including polar and tundra areas.
• Dormancy is a state in which plant growth or animal activity temporarily stops because of extreme cold or lack of light.
• Interdependence in cold environments means that plants, animals, climate and soil depend on one another for survival.
• A musk ox is a tundra animal with thick fur and large hooves that is adapted to survive extreme cold and snow.
• Permafrost is permanently frozen ground in polar and tundra regions that restricts plant growth and stores methane.
• Polar environments are the most extreme cold regions around the North and South Poles and are often covered by ice caps.
• Seasonal variation in cold environments means that they have short cold summers, even colder winters and extreme changes in daylight.
• Tundra is a treeless plain, mainly found around the Arctic Circle, with permafrost, low vegetation and a short growing season.
• Accessibility is a major challenge in cold environments because remote locations, ice roads and melting permafrost make transport and construction difficult.
• Heat impact occurs when buildings, roads or transport infrastructure warm the ground and cause permafrost to melt, making the land unstable.
• Mineral extraction in cold environments includes mining resources such as gold, copper and silver, often with damage to fragile ecosystems.
• An oil pipeline is infrastructure designed to transport oil across cold environments without melting the permafrost beneath it.
• Permafrost melt is a major challenge caused by climate change and development because it leads to unstable ground.
• Biodiversity loss happens when damage to cold ecosystems reduces species numbers and threatens animals that cannot adapt quickly enough.
• Conservation groups are organisations that campaign for sustainable management and stronger protection of cold environments.
• Endangered species are animals at risk of extinction, such as polar bears whose habitats are shrinking as ice melts.
• Fragile environments are environments that are easily damaged and recover very slowly, which is typical of cold regions.
• Global actions are international agreements and co-ordinated measures used to protect cold environments from exploitation and long-term damage.
• Land degradation in cold environments happens when permafrost is damaged or melts, reducing soil stability and plant growth.
• Sustainable management is an approach to development that protects cold environments in the long term while still benefiting local people.
• Technological solutions such as raised buildings, insulated pipelines and gravel pads help infrastructure function in permafrost areas.
• Wilderness areas are natural and largely undisturbed environments that provide important opportunities for research and conservation.
• Cold environments are areas where temperatures remain below 0°C for long periods and conditions are above freezing for only about three months each year.

• Classify biotic and abiotic components in a named ecosystem from a written or visual example.
• Construct a simple food chain for a named ecosystem by placing producers, consumers and decomposers in the correct order.
• Interpret a food web by predicting the effect of a change in one species on other populations.
• Explain how nutrient cycling helps maintain the balance of a small-scale ecosystem.
• Apply the idea of interdependence to explain how one abiotic or biotic change disrupts ecosystem balance.
• Compare the characteristics of major global biomes by using climate, vegetation and biodiversity evidence.
• Use latitude, precipitation, altitude, continentality and ocean currents to account for the distribution of global biomes.
• Identify producers, consumers and decomposers within a small-scale UK ecosystem from source material.
• Analyse how a named natural event or human activity could change a small-scale UK ecosystem.
• Assess whether management actions in a named small-scale UK ecosystem improved ecosystem health.
• Interpret climate and vegetation evidence to identify a tropical rainforest ecosystem.
• Explain how climate, water, soils, plants, animals and people are interdependent in a tropical rainforest.
• Relate plant adaptations such as drip tips, buttress roots, lianas and epiphytes to tropical rainforest conditions.
• Relate animal adaptations such as camouflage or climbing features to survival in tropical rainforest conditions.
• Analyse how rapid nutrient cycling and leaching affect soil fertility in tropical rainforests.
• Evaluate the importance of biodiversity in tropical rainforests to people and the environment.
• Distinguish between immediate and longer-term environmental impacts of deforestation.
• Explain how a named cause of deforestation can trigger further rainforest loss through secondary effects.
• Assess the economic benefits and environmental costs of deforestation in a named tropical rainforest case study.
• Evaluate the likely effectiveness of rainforest management strategies by weighing environmental, social and economic outcomes.
• Describe the physical characteristics of a named cold environment using climate, soil, vegetation and wildlife.
• Compare tundra and polar environments using temperature, precipitation, soils, biodiversity and human activity.
• Explain how climate influences permafrost, soils, vegetation, animals and people in a cold environment.
• Construct a chain of interdependence linking climate, permafrost, plants, herbivores, carnivores and people.
• Explain how permafrost thaw can affect plant growth, infrastructure stability and greenhouse gas release.
• Explain how a named plant adaptation helps survival in cold, windy, low-nutrient conditions.
• Explain how a named animal adaptation reduces heat loss, conserves energy or improves survival in snow and ice.
• Assess how low biodiversity makes a cold-environment ecosystem vulnerable to disturbance.
• Interpret maps, photos or data to identify opportunities for mineral extraction, energy, fishing and tourism in a named cold environment.
• Classify examples of development in a cold environment as mineral extraction, energy production, fishing or tourism.
• Use case-study evidence to explain why a named cold environment is attractive for economic development.
• Explain why extreme temperatures, seasonal darkness, remoteness and permafrost create development challenges.
• Assess the economic benefits and environmental costs of a named development activity in a cold environment.
• Explain how appropriate technology such as raised pipelines, stilts or gravel pads reduces damage to permafrost.
• Evaluate whether a named cold-environment development is sustainable.
• Justify management strategies that balance economic development with conservation in a named cold environment.
• Explain how governments, international agreements and conservation groups help protect cold environments.
• Assess the value of cold environments as wilderness areas for biodiversity, scientific research and future generations.