B3 - Human Affect on the Environment Flashcards
Give three effects of the growing population.
- More waste is produced.
- Human activity takes up more land.
- Raw materials are being used up rapidly.
Give three ways in which humans pollute water.
- Sewage
- Fertilisers
- Toxic chemicals from industry.
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Give two toxic chemicals that can pollute the land.
- Pesticides
- Herbicides
How can pesticides pollute the water?
When it rains, the chemicals are washed into streams.
What is eutrophication?
When oxygen levels in water fall so low that all aquatic animals die.
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Describe the process of eutrophication.
- Algae grows on top of existing algae.
- The algae on the bottom layer dies due to a lack of sunlight.
- The algae decomposes at the bottom of the lake.
- The decomposers uses the oxygen in the water when respiring.
- There isn’t enough oxygen to support other aquatic life.
What are bioindicators?
Species which can only be found in very clean or very polluted water.
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How is acid rain formed?
- Sulfur dioxide and nitrogen oxides are released when fossil fuels are burned.
- The gases dissolve in rainwater making it acidic.
Give two biological effects of acid rain.
- The ground becomes too acidic for trees as it destroys the roots.
- Rivers become too acidic for animals.
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Why don’t countries producing acid rain feel the effects?
Wind takes the pollution to other countries.
How are nitrogen oxides prevented from being released from cars?
Catalytic converters.
What is global dimming?
The release of particulates into the atmosphere.
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What are the results of global dimming?
- Sunlight is reflected.
- Less light hits the surface of the Earth.
- There could be a cooling of temperatures at the surface of the Earth.
What is deforestation?
The destruction of forest or woodland.
What are the consequences of deforestation?
- Carbon dioxide is released when the trees are burnt.
- Less carbon dioxide is absorbed from the atmosphere.
- Habitats are destroyed.
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How does deforestation lead to carbon dioxide being released?
- Burning the trees releases CO2.
- The dead vegetation decays which releases CO2.
Give a problem with a loss of biodiversity.
Sources of medicine or food could be lost.
How does deforestation reduce biodiversity?
The forest is often replaced by a monoculture.
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What two things are leading to more methane being released into the atmosphere?
- Rice fields
- Cattle
What is the effect of destroying peat bogs?
CO2 is released.
What is global warming?
An increase in the temperature of the surface of the Earth.
Give five effects of global warming.
- Big changes in the Earth’s climate.
- A rise in sea levels.
- Reduced biodiversity.
- Changes in migration patterns.
- Changes in distribution.
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What changes can be seen in the weather that are caused by global warming?
- Severe and unpredictable weather.
- Extensive flooding.
How does global warming cause a rise in sea levels?
Ice caps and glaciers melt.
What is the effect of rising sea levels?
Low-land flooding.
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How does global warming reduce biodiversity?
Organisms become extinct because of changing environments.
How does global warming change distribution?
-Some animals can extend their range as conditions become more favourable.
What are the two main types of biofuel?
- Ethanol-based fuels.
- Biogas
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What two plants are used for ethanol based fuels?
- Sugarcane
- Maize
Give two advantages of ethanol as a fuel.
- There are no toxic gases.
- The process of production is carbon neutral.
Give a disadvantage of ethanol as a fuel.
- A lot of land is needed to grow the plants.
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What is biogas?
A flammable mixture of biologically produced gases.
How is biogas formed?
Bacteria break down plant material or waste products of animals in anaerobic conditions.
Which gas is biogas mainly made of?
Methane
What is the optimum temperature for biogas producing bacteria?
30C
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Why are biogas generators built underground?
To provide insulation.
Why do short food chains make food production more efficient?
- Biomass is reduced at each stage.
- Having less stages reduces the loss of energy.
What is the most energy efficient way to produce food?
Grow and eat plants directly.
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Give two ways in which farmers get the maximum biomass from animals.
- Limiting the movement of food animals.
- Controlling the temperature of the surroundings.
How does limiting the movement of animals improve the efficiency of production?
- Animals don’t use as much energy in moving muscles.
- More biomass is used for growth.
How does controlling the temperature of the surroundings of animals improve the efficiency of production?
- Animals don’t use as much energy keeping warm or cooling.
- More biomass is used for growth.
What is sustainable food production?
Producing food in a way that can continue for years.
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What is the result of uncontrolled fishing?
Stocks of edible fish are falling.
Give three ways fish populations are conserved.
- Controlling the size of holes in nets.
- Bans on fishing in breeding season.
- Strict quotas imposed.
What is Fusarium?
A fungus.
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What is the rate of Fusarium growth at optimum temperature?
It can double in mass every five hours.
What is mycoprotein?
- Protein from fungus.
- Food produced from fungus.
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What conditions are present to give maximum mycoprotein yield?
- Air supply to provide oxygen.
- A stirrer to maintain a constant temperature and evenly spread oxygen and food.
- Water-cooled jacket to remove excess energy.
- Measuring instruments are present to ensure conditions are constant.
How is mycoprotein made edible?
It is given a range of textures and flavours of everyday food.
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Give five environmental problems of sourcing water.
- Dams destroy ecosystems.
- Flood plains with fertile soil disappear.
- Environments are destroyed by reservoirs.
- Reservoirs act as breeding grounds for mosquitoes.
- Dams may add to methane release due to eutrophication.
How do dams destroy ecosystems?
Huge areas dry out where rivers are lost.
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