Biology- Human influences on ecosystems

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  • Created by: Kitsune
  • Created on: 16-03-17 12:23
What are the advantages of monoculture?
Specific harvesting technique, highly selected characteristics, mineral and water requirements are easy to work out
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What are the disadvantages of monoculture?
Little variety of organisms, all are susceptible to the same disease, no genetic variety, soil is drained of minerals
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What are the advantages of crop rotations?
Reduces mineral depletion, improves soil texture, decreases need for pesticides, reduces pests
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Why does crop rotation reduce pests?
Their life cycle breaks with each rotation
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What are the disadvantages of crop rotations?
Increased cost, lower efficiency
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What are the advantages of hedges?
Shelter for animals, nesting for birds, roots improve soil stability
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What are the disadvantages of hedges?
Take up space for crops, compete for light with crops, consume water and nutrients that are for crops, may be a source of pests
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Define deforestation.
Rapid destruction of woodland
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What are the 6 results of deforestation.
Reduction in soil fertility, flooding, change in recycling materials, species extinction, climatic change
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Why do people destroy habitats?
Need for area for crops, livestock; extraction of natural resources, marine pollution
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What is famine?
Extreem scarcity of food
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What 5 things cause famine?
Increasing population, drought, flooding, unequal food distribution, cost of fuel and fertilizer
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What is pollution?
Any effect of human activities upon the environment
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What is a pollutant?
Any product of human activities that has a harmful effect on the environment
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What is an advantage of the greenhouse effect?
Better climate for plants
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What is an disadvantage of the greenhouse effect?
Climate patterns are messed up
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Why is radioactive pollution dangerous?
It leads to various forms of cancer
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How are non-biodegradable plastics dangerous?
Lead to water-logging of soil, choke animals, inhibit waste decomposition, release toxic gases when burnt
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What are the dangers of female contraceptive hormones ending up in waters?
Reduce sperm count in men, lead to feminization of aquatic animals
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Describe how eutrophication works.
Fertiliser leaks into a river. Algae growth increases. Algae start blocking sun for the plants at the bottom. Plants at the bottom die and bacteria feed on them. Bacteria population increases and oxygen concentration falls. Fish suffocate
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What are the two opposites of deforestation?
Reforestation and afforestation
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What do some species become endangered?
Pest control, commercial exploitation, loss of habitat
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What are the conservation of species strategies?
Restoring damaged habitats, creating new habitats, keeping the environment unchanged
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What is reclamation?
Restoring damaged habitats
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What is sanitation?
Removal of feces from waste water so that any pathogens they contain can't infect drinking water
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Describe a pit latrine
A huge hole is dug and all the waste is placed into it
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What are the advantages of a pit latrine?
Not water dependent and cheap
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What are the disadvantages of a pit latrine?
smell is unpleasant and sewage can overflow
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How does an activated sludge system destroy pathogens?
Using high temperature or chlorination
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Why does an active sludge system need to remove organic compounds?
Because they lead to biological oxygen demand
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Why do organic compounds lead to biological oxygen demand??
Microbes feed on them, multiply and use up oxygen
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Describe 4 steps in an activated sludge system
Sewage is inserted. Sedimentation allows grit to settle. Screening- a metal grid removes any materials that will block the pipes. First settlement tank allows suspended solids to precipitate as crude sewage sludge
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How are suspended solids treated in activated sludge systems?
They are anaerobically digested by bacteria and fungi to convert organic compounds into simple inorganic
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What are sustainable resources?
Ones produced as rapidly as are removed from the environment so they don't run out
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What is sustainable development?
Development providing for the needs of an increasing human population without harming the environment
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Are biomass fuels renewable?
No
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What are biomass fuels that are gases?
Methane and carbon dioxide
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What are biomass fuels that are liquids?
Alcohol, vegetable oil
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What are the advantages of using landfill sites to dispose of waste?
Economic in terms of space, away from people
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What are the disadvantages of using landfill sites to dispose of waste?
Allows bacteria and fungi to decompose, attracts disease spreading organisms
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What is incinerations?
Burning waste
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What are the advantages of incineration?
Plant is small and no pests are present
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What are the disadvantages of incineration?
Fuel needed, expensive to build, generates toxic fumes
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What is recycling?
Reusing waste products which would be thrown away
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Describe the 6 steps in recycling paper
1. It is sorted and delivered to the paper mill 2. Water is added and the mixture is turned into pulp 3. it is de-inked and cleaned 4. Pulp is rinsed and spread onto large flat racks 5. rolls press the water out 6. New paper ready
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Other cards in this set

Card 2

Front

What are the disadvantages of monoculture?

Back

Little variety of organisms, all are susceptible to the same disease, no genetic variety, soil is drained of minerals

Card 3

Front

What are the advantages of crop rotations?

Back

Preview of the front of card 3

Card 4

Front

Why does crop rotation reduce pests?

Back

Preview of the front of card 4

Card 5

Front

What are the disadvantages of crop rotations?

Back

Preview of the front of card 5
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