B7- ecosystems

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  • B7- learning from nature
    • Linear and closed loop systems
      • Linear- not sustainable
        • Things are being used quicker than being reproduced
        • produce waste
        • Energy is linear (can't be reused)
      • Closed loop
        • One part of the system's output becomes another parts input
        • Photosynthesis and respiration
        • Take-reuse-recycle
    • Natural ecosystems
      • Closed loop ecosystems
        • Barn owls
        • Masai people
    • Waste disposal
      • Cycling of materials
        • Dead organic matter
          • Any material that was once part of an living organism
          • Usually broken up by enzymes
      • Bacteria and nitrogen
        • Nitrogen fixing bacteria turn nitrogen into nitrates (in soil)
          • Plants the use the nitrates make protein and DNA
        • One type of decomposing bacteria break down proteins and amino acids into ammonium ions
          • Other bacteria turn the ammonium ions into nitrates
        • In anaerobic soil nitrates are turned into nitrogen (waterlogged or compacted)
      • Bacteria and carbon
        • Bacteria in soil turn carbohydrates in DOM (cellulose and starch)
          • Carbohydrates provide glucose for the bacteria to respire
            • The bacteria respire and turn it into CO2
        • Carbon originally taken from the atmosphere by photosynthesis
        • Carbon is a reactant that is recycled
    • Gains and losses
      • Abundance without waste
        • Transfer of pollen is called pollination
          • Pollen has the male sex cells in it
            • Needed to feritise female sex cells and produce seeds
          • Natural insurance policy
            • Producing lots of pollen increases the chance that more flowers will be pollinated
        • Basically producing loads to increase chances
        • In stable ecosystems all DOM decomposes and are recycled
      • Perfect closed loop systems
        • Don't need to worry about wasting energy because there is a constant supply from the sun
        • Most eco systems have both inputs and ouputs so are not perfect
        • A stable eco system has no overall gains and losses- the inputs and outputs are balanced
    • Ecosystem services
      • Include the different ways ecosystems provide for human needs
      • Clean water
        • perfect loop has been broken by deforistation
        • removing source of DOM
    • Dealing with waste
      • Non biodegradable waste cannot be broken up by enzymes
      • Plastics float down rivers into the sea
        • kill small animals that feed fish
        • Birds, fish and turtles cannot digest it
      • Bioaccumulation of toxic chemicals
        • chemicals called dioxins are made from bleached products
        • Dioxins, heavy metals and other chemicals accumulate in ecosystems
          • Heavy metals are linked to birth defects and cancer
          • Dioxins are linked to cancer, birth defects and problems with the immune system
        • Bioaccumulation is the slow release of chemicals
      • Waste doesn't build up in natural ecosystems
    • Sustainable food production
      • Humans remove biomass can cause irreversible changes
      • Euthorication
        • Nutrients from non organic fertilizers are washed into rivers and lakes
          • Cause algae to grow rapidly
            • Algae dies and decays in the water
              • Bacteria that causes the decay use up dissolved oxygen in the water
                • Causes oxygen levels to drop dramatically
                  • Kills animals in the water and plants  that would normally photosynthesise
      • Farmers use manure and organic fertilizers to make the systems closed
        • Crop rotation uses plants such as clover with nitrogen fixing bacteria in their roots
          • Use clover to replenish the soil with nitrogen compounds
      • Unsustainable fishing
        • Over fishing
        • Set laws on limits
    • Desertification
      • Preventing the land turning to desert
      • Herds are moved to avoid over grazing
      • Native species are adapted to it
    • Sustainable forests
      • Primary forests have never been cut down
        • Slowly being destroyed to meett he needs of local people
        • Loss of forests causes soil erosion, mud slides, silting of rivers, flash floods, loss of cloud cover and drought
      • Removing biomass changes a closed loop system into a linear one
        • Sustainable use of timber means replacing the trees and nutrients as quickly as they are taken away
      • Eco-labeling- shows wood is from  a sustainable forest
      • Forests are carbon sinks- store carbon in wood
    • Oil
      • Comes from dead bodies of minute animals and plants (lived in sea millions of years ago)
        • Heat and mass turn this biomass into oil
        • Sand and silt form over it and turn it into rock
          • Mine through the rock to allow the oil to flow up to the surface
      • Made of hydrocarbons
        • When burnt it is releasing energy from fossil sunlight
      • Being used quicker than can be replaced
      • Crude oil is easy to extract so most has been used up
      • Oil economy is a linear system
        • gives off CO2 plus other products made with oil like plastics and synthetic materials are not biodegradable
      • Plants grow quicker if there is more CO2 (natural negative feedback system)
        • Released when oil is burnt
    • The sun
      • Intensive farming causes pollution
        • Traditional methods do not provide enough food
      • Biofuels require land needed for food
      • Waste from industry can be reused so it is a "technical nutrient"
      • Sustainable model for manufacturing
        • Only biodegradable waste would be returned to soil
        • Energy would come from the sun or other sustainable energy sources
        • Apply closed loop systems to humans

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