B3 Humans And The Enviroment Flashcards
(41 cards)
How is the increase in the population affecting the enviroment?
More resources are needed to support the population.
People also have a better standard of living. This means that more energy and resources are needed to make things for them.
Unfortunately, many of theses resources are being used up faster than they are being replaced , meaning they will one day run out.
Why has the population increased?
There is more modern medicine and farming methods. The is reduced the number of people dying from disease and hungar.
How are humans producing too much waste?
The air is being polluted with gases like sulphur dioxide which can cause acid rain.
Toxic chemicals for farming, nuclear waste and household easte is polluting the land.
Sewage and toxic chemicals from industry are getting into rivers, lakes and oceans, affecting plants and animals that rely on them.
What human activities are reducing the amount of land available?
Building, farming, dumping waste, quarrying for metal ores.
How is carbon dioxide being stored?
It is sequestered on natural stores like:
Oceans, lakes and ponds.
Green plants where it is stored as carbon compounds.
Peat bogs.
What are the two main greenhouse gases?
CO2 and methane.
Explain deforestation.
It is the cutting down of forests. It is done to: Provide timber as a building material. Clear land to grow food, farm cattle or produce crops for biofuel. Produce paper.
What are the four main problems of deforestation?
More methane and co2 in the atmosphere, less co2 being taken in and less biodiversity.
Explain deforestation and more methane.
Rice is grown in warm, waterlogged conditions where the trees were. This means decomposes which produce methane.
Cattle also produce methane.
Explain deforestation and more CO2.
CO2 is produced she the wood is burnt.
Microorganisms feeding on dead wood produce CO2 when they respire.
Explain deforestation and less CO2 taken in.
There are less trees to absorb CO2 in photosynthesis.
Explain deforestation and less biodiversity.
It is the variety of different species in a habitat.
Tropical rain forests have a large number of different species. When they are destroyed many species may become extinct and biodiversity is reduced.
This means there could have been lots of useful products that were destroyed and we can’t use. They could have been new sources of food, fibres or medicines.
Explain the destruction of peat bogs and how this releases CO2.
Bogs are acidic and waterlogged areas of land. Plants can’t decay as there isn’t enough oxygen. The partly rotted plants build up.
They store carbon.
However bogs are drained so they are used as farmland or the peat it used as fuel or compost.
Then the bogs are drained, the peat decays producing CO2.
The demand for peat can be reduced if people buy peat free fertiliser.
How does global warming cause a rise in sea levels?
The sea water expands as it gets hotter. Also ice caps melt and this produces more water. This cusses sea levels to rise.
Those living in low-lying areas like the Netherlands, east anglia and the Maldives will be effected.
What are the consequences of global warming?
Rising sea levels.
More extreme weather like longer droughts and more hurricanes as they form over warm water.
Plant and animal distributions will change. Those that need a cooler environment have smaller areas to live and those who need hot environments will take over more space.
Biodiversity will be affected as some species won’t be able to survive the changes.
Different migration patterns. Some birds will migrate further north.
How are all biofuel made?
The fermentation of natural products is used. These can often be waste products.
Fermentation is when bacteria or yeast break sugars down by anaerobic respiration.
How is ethanol made?
Yeast breaks glucose down.
Glucose = ethanol + CO2 + energy.
Sugar cane juice can be used or glucose can come from maize starch when it is broken down by a carbohydrase.
The ethanol is distilled to separate it from the yeast and remaining glucose.
What is biogas usually made of ?
70% methane and 30% CO2.
How is biogas made?
Lots of different microorganisms can be used.
Plant and animal waste can be used which contains carbohydrates. Sludge waste from sewage works or sugar factories is used on a larger scale.
It is made in a digester called a generator or digester.
They must be kept at a constant temperature.
Biogas can’t be stored as a liquid so it must be used at once for heating, cooking, lighting or for making electricity.
How can biogas generators be used on in the developing world?
Small biogas generators can provide enough for a village or a family so they can cook.
Human waste, animal waste or food waste can be used.
By products are used to fertilise crops.
What are the two main types of biogas generators?
Batch and continuos.
Describe batch generators.
They create biogas in small batches.
Usually manually loaded with waste, which is left to digest and the by products are cleared away at the end of each session.
Describe continuous generators.
Biogas is made constantly.
Waste is continually fed in and biogas is produced at a steady rate. They are more suited to large scale projects.
What three things do all biogas generators have?
An inlet for waste to be put in.
An outlet for biogas and digested material.
