3- How Humans Effect The Environment Flashcards
What are the three main things humans pollute? And how?
Waterways - sewage and toxic chemicals
Air - smoke and gasses
Land - toxic chemicals (pesticides and herbicides)
How do people pollute the land?
Sewage - if parasites and chemicals are not treated
Household and industrial waste - chemicals (even radioactive) leak out
Farming methods - chemical fertilisers
Herbicides and pesticides
What are 1) herbicides and 2) pesticides?
1) weed killers
2) insect killers
Both poisons which get into the soil and therefore food chain
How do people pollute water?
Herbicides, pesticides and fertilisers are all washed into rivers
Untreated sewage
Toxic chemicals leaks from landfill
How do people pollute the air?
Burning fuels (produce eg. sulphur dioxide which forms acid rain)
What happens with acid rain?
Sulphur dioxide dissolves in water vapour in the air, causing acidic solutions to fall as acid rain which kills organisms and damages plant life
What is deforestation?
Many trees are cut down - often in tropical areas for timber and agricultural land
What effects has deforestation had?
Increase the release of carbon dioxide in the atmosphere
Reduced the rate that carbon dioxide is removed for the atmosphere
Reduced biodiversity
Why do humans do deforestation?
So crops can grow to produce ethanol based biofuels
Cattle and rice fields (produce methane)
How has the destruction of peat during deforestation effected the atmosphere?
Increase of carbon dioxide.
It is used as compost, which is decayed by microorganisms - releasing carbon dioxide
In the normal balance of nature, what is carbon dioxides cycle?
It is released into the air by respiration and removed by plants and algae (also dissolving in the earths waters)
What is greenhouse gasses and what do most scientist believe about them?
They are the levels of carbon dioxide and methane in the atmosphere
Most scientists believe they contribute to global warming
What could a slight increase in the Earth’s temperatures do?
Cause noticeable changes to the climate A rise in sea level (the ice caps melt) Reduction in biodiversity Change in bird migration Distribution of species changes
What are biofuels? Give two examples
Fuels made from natural products
Ethanol based fuels
Biogas
How are ethanol based fuels produced?
By anaerobic fermentation
Microorganisms respire anaerobically to produce ethonal (using sugars from crops as energy)
Glucose is produced from maize starch through carbohydrate which can be fermented by yeast to produce ethanol
What is the advantage to distilling ethanol and using it as a fuel in motor vehicles?
It is carbon neutral - the carbon dioxide used for photosynthesis is returned to the atmosphere when ethanol is burnt
How can biogas be produced?
During anaerobic fermentation by bacteria
Plants and waste (containing carbohydrate) can be broken down in biogas generators which provide idea conditions for bacteria.
Describe biogas generators?
Suitable temperature with oxygen free conditions, well insulated with insulating jackets. Some are designed to mix the contents
What is the gas produced by a biogas generator used for?
Fuel that provides energy for heating. The more methane the better
How can we produce meat more efficiently?
Preventing the animal from moving (wasting energy)
Keeping the animals in warm conditions so energy isn’t wasted on maintaining body temperature
What does sustainable food production involve?
Managing resources
Finding new types of food (mycoprotein)
Hunters/fishermen are monitored and restricted
What is mycoprotein?
Aerobically grow on cheap sugar syrup by the fungus ‘fusarium’ it is a protein rich food suitable for vegetarians
What is a fermenter?
Where microorganisms can be grown on a large scale.
It’s conditions must be controlled to ensure maximum growth
Features of an industrial fermenter?
Air supply providing oxygen
A stirrer to keep microorganisms spread out
A water cooled jacket to balance the heat from the respiration
Sensors to monitor pH and temperature
