Topic 7 Flashcards
What are biomes
Large scale ecosystems with distinctive vegetation
What does an ecosystem include
All the living and none living things in an area
What determines what type of biome forms
Climates
Climate for tropical rainforest
Same all year round: hot, wet
Temp is 20°-28° - near the equator
Lots of sunshine all year, 12 hour days all year
2000mm of rainfall a year
Characteristics of the tropical rainforest
Most trees are evergreen
Lots of different species of animals – dense vegetation provides lots of food and different habitats
Constant supply of nutrients in the soil – plants grow quickly and shed leaves all year round
Temperate forest climate
Mild, wet
1500 MM of rainfall a year
Day shorter in winter and longer in summer
Characteristics of temperate forests
Mild wet climate supports fewer plant species: forests have broad leaf trees that drop leaves in autumn
Range of plants provides food for lots of mammals
Plants lose leaves in autumn, leaf litter decomposes quickly, soil relatively thick and nutrient rich
Boreal forest climate
Cold, dry
Short summers long winters
Precipitation less than 500 MM a year
Lots of daylight during summer months, little or noneduring winter
Boreal forest characteristics
Most trees are evergreen: commonly coniferous trees, mosses and lichen also
Few animal species because less food available and animals must be adapted to cold
Soil thin, nutrient poor and acidic due to cold climate decomposing slowly
Tropical and temperate grassland climate
Tropical grasslands have low rainfall ( 800 to 900 MM per year) and distinct wet and dry seasons.Temps range from 35° to 15°. Lots of sun all year round
Temperate grassland temps range from 40 – -40. 250–500 MM rain per year. Amount of light varies through the year
Characteristics of tropical and temperate grasslands
Tropical grasslands have mostly small plants and grass with few trees. Home to lots of insects and larger animals e.g. giraffes. Grass dies back during dry season to form thin, nutrient rich soil but these are washed out of soil during wet season
Temperate grasslands have lots of grasses in small plants and a few trees. Home to fewer animals than tropical grasslands e.g. wild horses. Higher temps in summer me.decomposition is fast, soil is relatively thick and nutrient rich
Desert climate
Rainfall low – less than 250 MM per year
Temps range from 45° - 0°
More daylight during summer, little cloud cover, lots of sunlight hours a day
Desert characteristics
Plant growth sparse due to low rainfall e.g. cacti
Few animals. Only those adapted to harsh climate e.g: lizards
Little leaf litter and decomposition is slow due to dry climate, soil is mostly thin and nutrient poor
Tundra climate
Temps from 10° in summer and -30° in winter
Precipitation low – less than 250 MM per year
Tundra found at high latitudes, near continuous daylight in summer and little daylight in the winter
Tundra characteristics
Hard for plants to grow due to cold climate and lack of light, plants include mosses and low shrubs
Cold climate and lack of vegetation means that relatively few animal species in tundra e.g. arctic hares
Sparse vegetation produces little leaf litter ,decomposition slow ( cold, dry climate ), soil is thin nutrient poor
What local factors effect biome distribution
Altitude – high altitude are colder, fewer plants grow there, less animals
Rock type - rocks can be easily weathered to form soils, different rocks contain different minerals.Can affect how nutrient rich soil is
Soil type – more nutrient rich soil support more plants, acidity and drainage of soils also varies
Drainage – if drainage is poor, so gets waterlogged and only plants adapted to wet conditions can grow
Biotic and abiotic components interacting
Water availability effects the plants that can grow, plants take in and release water into atmosphere providing moisture for more rainfall
Type and desnity of vegetation affects type of soil that forms, and soil type affects plants that can grow, lots of vegetation provides leaf litter for nutrients to go into soil
Some organisms cause biological weathering
What respurces does the biosphere provide
Food - indigenous people and farmers can rely on food provided by biosphere e.g plants and animals
Medicine - plants can have medicinal properties, 7000 drugs created from plants in tropical rainforests
Building materials - trees and plants used for timber and to make furniture
Fuels - wood, moss and animal dung can be burned for fuel
How do humans exploit the biosphere
Energy: population increase and increasing wealth means that more forest is cut down to grow crops, make coal mines and powerstations
Water: demand for water is increasing, this causes the over exploitation of natural water stores which leaves animals without water
Minerals: metals can be used for: building and electronics. Demand is increasing and mkre mines are set up which deforest and pollute the rainforest which kills animals and plants
How does the biosphere control proportions of gases in the atmosphere
Plants take in co2 and release oxygen in photosynthesis
Animals take in oxygen and give out co2 in respiration
How does the biosphere maintaining the balance of gases in the atmosphere important?
Organisms need oxygen to survive
Increased Co2 leads to global warming
Increased Co2 leads to acidic oceans
Some Co2 is needed to keep the earth warm
How does the biosphere keep soil healthy
Plant roots and animals spread nutrients through soil which maintain soil structure and fertility
Roots hold soil together which stops erosion from wind and rain
Vegetation intercepts rain to prevent leaching
How does the biosphere regulate the water cycle
Water taken up by plants so less reaches river and causes floods and soil erosion
Plants help to regulate the water cycle by storing water and releasing it slowly into the atmosphere
Why are forests essential in maintaining the balance of gases
They take in huge amounts of Co2 and release huge amounts of oxygen
How is population growth increasing the demand for resources
More people require more resources such as food, water and energy so demand rises
Increased demand for one thing may increase the demand for another:
More food needed means that more water is needed, this must be transported in mass which requires more energy
How does increasing wealth increase demand for resources
More disposable income:
More money for food, buy more than they need
Can afford cars, fridges, TVs which all use energy. Manufacturing these requires energy and uses water
Water use increases as more people can afford flushing toilets and showers
How does urbanisation increase demand for resources
Growth of proportion of people living in urban areas
Cities are more resource intensive than rural areas e.g. streets light use energy and fountains use water
Food and water must be transported long distances to meet increased demand in cities, a d waste must be removed - this uses energy
How does industrialisation increase demand for resources
Shift in countries main economic activity from primary to secondary sectors
Energy is used when manufacturing cars, chemicals and electrical appliances
Manufacturing uses a lot of water
Industrialisation increases the production of processed goods which uses lots of palm oil which are grown in huge plantations
What is Malthus’ theory
Population is increasing faster than resource amount
When population outgrew resource amount ( point of catastrophe ), people would die from famine, illness and wars until population decreased to a level that could be supported by respurces available
What is Boserup’s theory
However big the population grew, people would find a way to produce sufficient resources to support it
People would come up with new ways to increase production through technology to avoid catastrophe
