7 - Biomes Flashcards
Define biome and ecosystem
Biomes are large scale ecosystems with with similar characteristics
An ecosystem are communities of interacting biotic and abiotic features in an area
Describe the tropical forests biome
No definite season - same climate all year round
Hot temperature due to being on the equator where the sun is overhead all year round (20-28)
Day length the same all year round (12hrs)
High rainfall (2000m a year)
Describe the temperate forests biome
Have 4 distinct seasons - warm summers, cool winters
Very high rainfall all year round (1500mm per year)
Shorter days in winter and longer in summer - varying hours of sunshine throughout the year
Describe the boreal forests biome
Short summers, long winters
Cold forests
Very low avg winter temps (-20) and low avg summer temps (10)
Low precipitation (<500m a year) - a lot of this falls as snow
Lots of daylight in summer months but little/none in winter
Describe the tropical grassland biome
Low rainfall (800-900mm a year)
Distinct wet and dry seasons
Temps highest (35) just before the wet season and lowest (15) just after
Found at equator so lots of sunshine
Describe the temperate grasslands biome
Hot summers (up to 40)
Cold winters (down to -40)
Receive low precipitation each year - but most in late spring/early summer (250-500mm a year)
Further from equator so sunshine varies in the year
Semi-arid
Describe the deserts biome
Very low rainfall
Very hot day temps to cold at night (45-0)
Get more daylight in summer than winter
In the tropics
Arid
Describe the tundra biome
Low temperatures - (5-10 in summer & -30 in winter)
Very low precipitation - less than 250mm & most falls as snow Lots
Found at high latitudes so gets continuous daylight in summer & little/none daylight in winter
What factors alter the biome distribution?
Mainly climate (largely influenced by latitude since sun’s energy more concentrated so higher temps) - temp, precipitation, sunshine hours
Local factors - altitude, rock and soil type, drainage
How is biome distribution affected by local factors at a smaller scale?
Altitude - higher altitudes are colder so fewer plants grow there, limiting animal species & thin soil is there, relief rainfall
Rock type - some rock types are easily weathered to form soil and different rocks have different minerals, affecting how nutrient rich the soil is. Some are permeable/impermeable
Soil type - more nutrient rich soil supports more plants
Drainage - if drainage is poor, soil gets waterlogged meaning only plants adapted to wet conditions can grow there
Define the biotic and abiotic factors
Biotic components are the living parts of a biome eg flora, fauna
Abiotic components are the non living parts eg soil, water, rock, atmosphere
How do the biotic and abiotic factors of biomes interact?
- Water availability affects the plants that can grow & plants take water from the soil and release it to the atmosphere providing moisture for further rainfall
- The type & density of vegetation that grows affects the type of soil that forms, which in turn affects the type of vegetation that can grow
- Some organisms cause biological weathering when rocks in the ground are broken up into smaller pieces by
What does the biosphere provide for indigenous and local people?
Food - from plants & animals, growing crops etc
Medicine - lots of plants have medicinal properties and are used to cure illnesses and keep ppl healthy
Building materials - trees and other plants used as building materials, sap from trees used as glue or for waterproofing & straw used for roofs
Fuel resources - dried animal dung, wood, moss, dried grass all burnt as fuel & some use animal fat as fuel for oil lamps
How are humans exploiting the biosphere?
Energy - as pop increases and ppl have more electric devices. Deforestation to clear land to make power stations/coal mines
Water - as pop increases, demand increases. Water sources over-exploited meaning plants & animals no longer have enough water to survive, water extraction causes competition
Mineral resources - minerals used in building, scientific instruments, electrical appliances etc. Extracted by mining which leads to deforestation and toxic chemicals washed into rivers killing wildlife. Open pit mining removes large area of land surface
How does the biosphere regulate the composition of the atmosphere?
Plants take in co2 and give o2 during photosynthesis
Animals take oxygen and give co2 through respiration
Important to keep Earth warm enough to support life, but not global warming. Most organisms need oxygen to survive and increased co2 can lead to acidic oceans
Natural forest fires release trapped carbon and removes litter which decomposes slowly in arid areas
How does the biosphere maintain soil health?
Roots of vegetation hold soil together preventing erosion of soil by wind/rain
Nutrient cycling: decomposing vegetation rots, returning important nutrients for soil formation
Vegetation intercepts rainfall before it reaches ground, preventing leaching - where nutrients in the soil are washed downwards out of reach of plants
How does the biosphere regulate the water cycle?
Water is taken up by plants so less water reaches rivers preventing soil erosion and flooding
Plants regulate the hydrological cycle by storing water and releasing it slowly to the atmosphere, reducing risk of flooding (photosynthesis and transpiration)
What main factor is increasing demand for food, energy and water resources?
Increasing pop, requires more resources so demand increases
More demand for food means more needs to be grown increasing demand for water which in turn increases energy for transportation
What other factors are increasing demand for food, energy and water resources?
Increasing wealth - wealthier people have more disposable income meaning they have more money to spend on luxuries which use these resources more
Urbanisation - increases resource consumption since cities are ore resource-intensive than rural areas using more energy & urban parks require water. Food & water have to be transported long distances to meet city demands
Industrialisation - manufacturing goods uses lots of energy and water (washing,cooling) increasing demand
Also increases demand for production of processed goods eg margarine
What is Malthus’s theory? Give a drawback
Population growth increasing faster than supply of resources so there’d be too many people for the available resources
When this happened, people would be killed by catastrophes such as famine illness and war and the pop would return to a level that could be supported
Food production has kept up with the pace of of pop growth so far
What is Boserup’s theory? Give a drawback
People would always produce sufficient resources to meet the needs no matter how big the population grew
If resource supplies became limited, people would innovate come up with new ways to increase production to avoid hardship
Many people are still hungry
