B3 - The effects of the population Flashcards
What do humans pollute?
Humans pollute:
• Waterways with sewage, fertiliser and toxic chemicals
• Air with smoke and gases eg. sulphur dioxide
• Land with toxic chemicals eg. pesticides and herbicides
Why does building houses for humans affect animals and plants?
Land has to be cleared, which destroys their habitats.
Why must sewage be treated?
Sewage must be treated properly to remove guy parasites and toxic chemicals or these could get into the land.
Why does landfill cause pollution?
Landfill causes pollution because toxins leak out into the surrounding soil and into underground water.
Name three affects of land pollution.
- Toxic chemicals from landfills can leak out and destroy soil
- Chemical fertilisers can be washed into rivers
- Poisons sprayed onto crops can get into the soil and into the food chain
Name three reasons for water pollution: a
- Herbicides, pesticides and chemical fertilisers all get washed into rivers and streams
- Fertilisers and untreated sewage can cause a high level of nitrates
- Toxic landfill chemicals can leak into waterways and pollute the water, killing organisms eg. fish
How might farmers keep their land fertile?
Farmers may use chemical fertilisers to keep the soil fertile, which can be washed into rivers.
What is the definition of parasite?
Organism which lived in it on other living organisms and gets some or all of its nourishment from its host organism.
What’s the definition of fertile?
A fertile soil contains enough minerals (eg. nitrates) to supply the crop plants with all the nutrients needed for healthy growth.
How are birds affected by acid rain?
Acid rain can cause damage to trees, a source of food and habitat for birds.
How do humans cause air pollution?
Humans cause air pollution by:
• Burning fuels - sulphur dioxide + acidic gases
• Power stations and cars - Acidic gases
Why does acid rain affect areas a long way from where the sulphur dioxide is released?
Sulphur dioxide is blown by winds before it dissolves in the rain.
What is the definition of deforestation?
Deforestation means that many trees are cut downs
Which process removes carbon dioxide from the air?
Photosynthesis
Why has deforestation occurred?
So that:
• Crops can be grown to produce ethanol based biofuels
• There can be increased in cattle and rice fields for food
What the affects of deforestation?
- Reduced rate at which carbon dioxide is removed from the air
- Reduced biodiversity due to loss of food and habitats
- Increased release of methane in the atmosphere
What is the definition of biodiversity?
The variety of animals and plants in a particular area or the world.
How is carbon dioxide sequestered?
Carbon dioxide is removed from the air by plants in photosynthesis and by dissolving in oceans, rivers and lakes.
Why might sea levels rise in the future?
If the climate gets warmer the ice will melt.
How is ethanol extracted from the fermenter?
By distillation
Why is ethanol described as carbon neutral?
Ethanol is described as carbon neutral because only the carbon dioxide used for photosynthesis by the crops is returned to the atmosphere when the ethanol is burned.
Which gas is the fuel in biogas?
Methane
Why are farm animals sometimes kept in warm sheds?
More of their energy used to maintain their body temperature, can be converted into new growth.
Why is it more efficient for us to eat plants than it is to eat animals?
The shorter the food chain, the less energy is wasted.
Why can’t fishermen remove small, young fish?
Fishermen cannot remove small, young fish because the population could become extinct if the young fish don’t grow and reproduce.
What type of food is produced by Fusarium?
Mycoprotein
What are the features of industrial fermenters?
- Air supply - oxygen for respiration
- Stirrers/gas bubbles - keep microorganism spread out and evens out the temperature
- Water-cooled jacket - on outside to prevent overheating
- Sensors to monitor both pH and temperature
Why must biogas be produced anaerobically?
In aerobic respiration, the bacteria would produce carbon dioxide, not methane.
Why is it important to prevent species from becoming extinct?
There may be unknown benefits to the human population that species can provide.
Explain how greenhouse gases may cause droughts and rising sea levels.
- Reduce heat that is radiated by the Earth into space
- So more heat is radiated back to Earth
- Causes global warming
- Melts polar ice caps, rising sea levels and climate change
Give one way the efficiency of human food production can be increased.
- Reduce the stages in the food chain
* Less energy is lost between the stages
Give two ways in which global warming might affect species on a worldwide scale.
- Loss of habitats
- Changes in distribution
- Changes migration pattern
Name two gases produced by burning fossil fuels.
- Sulphur dioxide
* Nitrogen oxides
Describe three different ways in which people have reduced the amount of land for wild animals and plants.
- Building of roads
- Cleared land for building houses
- Industrial farming
