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19 Cards in this Set
- Front
- Back
How is energy transferred?
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•Through consumption of organisms by other organisms.
•Energy locked up in parts that cannot be eaten (bones, faeces etc.) get recycled back into the ecosystem by decomposers. |
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Why doesn't all energy get transferred to the next trophic level?
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Around 90% is lost in various ways.
•Around 60% of the energy isn't taken in, in the first place. -plants can't use all light energy. -bones, faeces, roots etc. aren't eaten by organisms. -some parts of the food is indigestible and pass through organisms. •40% absorbed energy called "gross productivity". This isn't all available to the next trophic level either. -30% of total energy lost to the environment, maintains body heat, respiratory loss. -10% of total energy becomes biomass, stored or used for growth, net productivity. Net productivity = gross productivity / respiratory loss |
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What is a natural ecosystem?
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An ecosystem that hasn't been changed by human activity.
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What is the energy input of an ecosystem?
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The amount of energy captured by the producers in an eco system.
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What is intensive farming?
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Involves changing an ecosystem by controlling the biotic and abiotic conditions to make it more favourable for crops and livestock.
Crops and livestock can have greater net productivity. |
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How does intensive farming increase productivity?
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•Increase efficiency of energy conversion.
•Remove limiting growth factors. •Increase energy input. |
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How does intensive farming increase productivity?
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•Increase efficiency of energy conversion.
•Remove limiting growth factors. •Increase energy input. |
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What are pests?
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Pests are organisms that reduce productivity of crops. By reducing the amount of energy available for growth.
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What chemical pesticides are used?
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Herbicides - kill weeds that compete for energy.
Fungicides - kill fungal infections that damage crops, less energy used for fighting infection. Insecticides - kill pests that eat and damage crops |
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What are environmental and economic issues with chemical pesticides?
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Environmental:
•May Directly kill/damage non pest species, (butterflies etc.) •Indirectly kill/damage non pest species. Secondary consumers eating poisoned primary consumers. Economic: •Expensive, may not be profitable for farmers to use them. |
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What biological agents are used?
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Natural predators - eat pest species.
Parasites - live in/lay eggs on pest insect. Pathogenic - bacteria and viruses used to kill pests. |
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What are environmental and economic issues with biological agents?
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Environmental:
•Natural predators may become pests themselves •Can affect other non-pest species. Economic: •May be less cost-effective than chemical pesticides. |
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How are integrated systems useful for getting rid of pests?
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•Combined effect reduced pests more than either method alone.
•Reduce costs. •Reduce environmental impact because less of either is used. |
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What types of fertilisers are there?
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1.Natural fertilisers - organic matter (sewage /manure).
2.Artificial fertilisers - inorganic (pure chemicals). |
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What are economic and environmental issues of using Fertilisers?
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Environmental:
•Can be washed into rivers and ponds, killing plants and fish. •Changes balance of nutrients in soil, too much of one can cause plants to die. Economic: •Farmers need to get the amount of fertiliser they apply just right, too much and they loose money (fertilisers washed away). Too little and productivity won't increase. |
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Why do some farmers intensively rear livestock?
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So that more of the energy can be used growth to increase biomass.
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How are livestock intensively reared?
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1.Kept in warm, indoor pens where movement is restricted. (Less energy wasted on keeping warm and moving around)
2. Animals fed higher energy feed, increases energy output so more available for growth. |
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How are livestock intensively reared?
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1.Kept in warm, indoor pens where movement is restricted. (Less energy wasted on keeping warm and moving around)
2. Animals fed higher energy feed, increases energy output so more available for growth. |
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What are the benefits of intensive rearing?
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More food in a shorter space of time at lower cost.
However some people believe it can cause the animals pain and distress and should not be done. |