1.) Used in respiration, converted to CO2 and H20. Excreted. 2.) Some biomass is not consumed eg: cellulose, cell wall, bones, hair etc.
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What are the units for pyramids of energy?
Kj-2 year-1
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How can energy be lost?
Heat, chemical energy in uneaten plant material, movement.
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Why are fertilisers needed?
Farming breaks nutrient cycle so soil gradually depleted of minerals.
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Advantages of inorganic fertilisers?
Very effective, easy application, tailored to crops requirements, known nutrient content, no pests present, nutrients are concentrated so only a small amount needed.
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Disadvantage of inorganic fertilisers?
Nitrate and ammonium ions soluble so quickly leached out of soil into rivers causing eutrophication. Expensive and manufacture is energy intensive.
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Advantages of organic fertilisers?
Nutrients released slowly as they are decomposed- prevents leaching and lasts longer. Improves soil structure, cheap, improves soil aeration, alreadry available so no cost.
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Disadvantage of organic fertilisers?
Less concentrated in minerals so need to use more, may contain unwanted substances, requires heavy machinery to spread.
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Describe the process of eutrophication.
Sudden algal growth produces oxygen, Larger plants out-competed and die. No photosynthesis from submerged plants. Algae grow faster than consumers.Increase in detritus, saprobionts inc use up o2 faster than replace. Large animals die.
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Advantage of chemical pest control?
Acta quickly. Applies to specific area. Kills most pests.
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Disadvantage of chemical pest control?
May accumulate in food chains and kill animals.
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Advantage of biological pest control?
Reduce pest population to level where it can do no harm. Attacks pest only. One application required. Pests cannot become resistant. Less chemicals used.
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Disadvantage of biological pest control?
Slow acting. May become a pest itself. Does not get rid of pests completely.
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Conditions of intergrated pest control.
1.)Only take action is pest population is above economic threshold. 2.)Use suitable cultural methods.Use biological control if exceeding threshold. 4.) Chemical pesticides at low and controlled dose at best time of year. 5.)Effect evaluated.
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How does keeping animals indoors increase biomass?
Kept warm by body heat. Less energy lost through respiratory heat. Don't expend energy in muscle contraction.
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How does the high energy food help in factory farming?
Quick growth-sold sooner. Low in plant fibres so easy to digest. Mineral and vitamin supplements.
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Why are animals slaughtered before growth stops?
Reduces food wasted, earns early profit.
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How is energy transferred into biomass?
Light absorbed by chlorophyll molecules, converted to chemical energy, stored as starch.
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Two features that a predator must have to be a successful biological control agent.
Attack pest only. Only one application as biological control agent reproduces.
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Equation for net productivity.
Gross productivity-Respiratory losses
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How can the use of insecticides poison animals at top of food chain?
Accumulates in tissue and becomes concentrated high up in food chain due to bioaccumulation.
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Other cards in this set
Card 2
Front
Why is biomass lost?
Back
1.) Used in respiration, converted to CO2 and H20. Excreted. 2.) Some biomass is not consumed eg: cellulose, cell wall, bones, hair etc.
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