Geography people and biosphere

• Biome


  Global-scale ecosystem that exists throughout the world, categorised by similar environmental characteristics such as climate, vegetation type and soil
• Biomes usually occur in latitudinal belts, meaning they are present across the world at similar latitudes (horizontally on a typical map)
• Latitudinal patterns occur because the climate in these regions is similar due to atmospheric circulation
• There are some variations in biome distribution due to other influences, like ocean currents, winds and land-sea temperature differences
• Tundra


  • Harsh, cold winters and extremely short summers
  • Treeless ecosystem as it is too cold and not wet enough for trees
  • Precipitation is extremely low (10-25cm/yr)
  • Short growing season, nutrient poor soils and lack of biodiversity
  • Animals are usually migratory
  • Soils are permanently frozen (permafrost)
• Taiga


  • Coniferous forest (conifers) which are drought resistant, cone-bearing trees
  • They retain their leaves all year round to maximise photosynthesis, especially during short summers
  • Around 50cm/yr of rainfall and a longer growing season, meaning there are more plants
  • Small animals and migrating birds are present
  • Coniferous forests may also contain wolves, bears and moose
• Temperate deciduous forest


  • Deciduous vegetation (broad-leaf trees that shed their leaves in winter to retain moisture)
  • Oak, maple, beech trees
  • Highly seasonal temperatures: hot summers and cold winters
  • Moderate precipitation
  • Animals include deer, bear and small animals
• Temperate grassland (prairie, steppe, pampas)


  • Dominant vegetation is grasses
  • Low precipitation (25-75cm/yr)
  • Hot summers, cold winters
  • Animals include prairie dogs and originally bison, although these were overhunted in the past
• Desert


  • Precipitation is extremely low - under 25cm/yr
  • Temperature fluctuates from well above 20°C in the day to below 0°C at night
  • Precipitation greatly limits plant growth, soil is very low in nutrients and high in salts. Mainly cacti and sagebrushes
  • Small animals live in deserts, often nocturnal to regulate body temperature
  • Deserts cover one fifth of the world's land surface
• Tropical rainforest


  • Species rich ecosystem with over half of the world's species of plants and animals
  • Warm, moist climate throughout the year with little variation, perfect for plant growth
  • Precipitation is extremely high (200-450cm/yr)
  • Very quick nutrient cycle soils are nutrient poor but there is a thin layer of organic matter on the top of soils that makes plants very productive
  • Animals include many insects, reptiles and amphibians
• Savanna (tropical grassland)


  • Temperature varies little throughout the year staying in the high 20°Cs
  • Precipitation is very seasonal, with distinct wet and dry seasons. Yearly precipitation is around 76-150cm/yr, though most of this falls in winter
  • Tropical grassland dry seasons are characterised by wildfires, and the vegetation is adapted to this
  • Wide expanses of grass means this ecosystem is often used for animal grazing
  • Hoofed animals and herds are common in this ecosystem, as well as large predators like lions and leopards
• High pressure


  Dry
• Low pressure


  Rainy
• Cold

  Tundra
• Warm


  Tropical grassland, tropical rainforest
• The distribution and characteristics of biomes are affected by the climate (e.g precipitation, temperature and sunlight exposure)
• The climate has major influence over the type of vegetation that can grow, what animals can survive and what the soils are like in a particular biome
• Forest biomes are found in areas of low pressure as these climates are rainy, which support tree growth
• Grasslands and deserts are found in areas of high pressure as precipitation is too low for forested ecosystems
• Around the equator, the sun shines directly onto the land, making it very warm. This causes plants to be more productive (when there's enough rain), creating tropical rainforest biomes
• At higher latitudes, sunlight becomes less intense and sunlight becomes more seasonal, influencing the type of vegetation that can grow. At the poles, the low temperatures, low precipitation and lack of light limit plant growth
• Altitude


  • The temperature gets colder with increasing height. For every 1000m change in height, temperature drops by around 6.5°C
  • Precipitation usually increases with height, which alters the vegetation and soil at different altitudes
• Altitudinal zonation refers to the pattern we see on hills and mountains where the ecosystem changes with increasing elevation
• Rock and soil type can cause major differences in vegetation and wildlife in a particular area
• The bedrock of an area also influences soil composition and grain size (e.g. whether it is a sandy soil or a clay soil etc.), which affects things like permeability, vulnerability to erosion and drainage
• Drainage

  • Well-drained soils do not retain excess water, whereas poorly drained soils can be left waterlogged and boggy
  • Drainage is influenced by different local factors, such as topography and relief, soil type, amount of vegetation, precipitation and temperature
• Biotic components


  Living organisms, such as plants (flora) and animals (fauna)
• Abiotic components


  Non-living environmental factors which have influence over the ecosystem such as climate (temperature, humidity and precipitation), light exposure, soil type, rock type, the atmosphere, water availability etc.
• Biotic and abiotic interactions

  1. Plants take up carbon dioxide in the atmosphere during photosynthesis and convert it into energy (glucose)

  2. Plants give out oxygen during photosynthesis, which goes into the atmosphere and is taken up by animals

  3. Animals give out carbon dioxide during respiration, which goes into the atmosphere and is taken up by plants

  4. When animals and plants die, they are broken down by decomposers. Decomposition releases nutrients into the soil, where they are taken back up by plant roots

  5. Water falls as precipitation and is taken up by plants and animals. Water is lost through urinating, respiration or when organic matter decays, where it is transferred back into the atmosphere

  6. Water breaks up rocks through weathering, which releases chemicals into the soil. These chemicals are taken up by plants and used as nutrients to help them grow. They are then passed onto animals when they eat plants, and put back into the soil when they decompose
• Biosphere


  The living layer of Earth between the atmosphere (air) and the lithosphere (crust) where all plants and animals are found
• Goods provided by the biosphere

  • Food and water: Meat, berries, crops, nuts etc.
  • Energy sources: Fossil fuels, timber (for burning)
  • Materials: Metal, rock, wood and other raw materials for building, medicine, or to process into other things (e.g. cotton for clothes)
• Services provided by the biosphere

  • Atmosphere regulation: The production and maintenance of gases in our atmosphere for respiration, photosynthesis and the greenhouse effect
  • Soil formation and nutrient cycling: The transfer of nutrients through plants and animals into soil, and back into plants and animals, allowing growth and reproduction
  • The hydrological cycle: The movement and purification of water throughout the biosphere, allowing humans to have drinking water and sanitation/hygiene
• Indigenous peoples are the earliest known settlers in an area, making them native to that land
• When indigenous peoples originally settled in areas in the past, they relied heavily on ecosystem goods and services provided by the biosphere
• Food and water


  • Meat
  • Berries
  • Crops
  • Nuts
• Energy sources


  • Fossil fuels
  • Timber (for burning)
• Materials


  • Metal
  • Rock
  • Wood
  • Other raw materials for building, medicine, or to process into other things (e.g. cotton for clothes)
• Services


  Processes in the biosphere that support life
• Services provided by the biosphere

  • Atmosphere regulation
  • Soil formation and nutrient cycling
  • The hydrological cycle
• Atmosphere regulation


  The production and maintenance of gases in our atmosphere for respiration, photosynthesis and the greenhouse effect