Food
List-how has modern technology helped to increase food production
1. Machinery
2. Fertilisers
3. Pesticides
4. Selective breeding
What is a greenhouse gas
they are gases that keep the earth warm by reflecting infrared radiation back to the earth's surface
how can recycling help to conserve resources
it can help reuse things which would otherwise be thrown away. it sometimes reuses non renewable resources. this increase its life.
Explain 2 problems with the global food supply
Uneven food distribution-there is enough food for everyone on earth yet many do not get enough food. some parts of the world produce more food than others and although large amounts of food are supplied to areas with less food, there is still not enough food for everybody.
Famine-there may not be food produced in a certain place for years if there is no rainfall. animals and people die. sometimes it rains too much and destroys the crop. sometimes wars prevent people from farming.
Importing issues-importing can also increase food price, making it hard for people to buy it.
Explain greenhouse effect
greenhouse gases allow shortwave radiation from the sun to pass through them, and once the rays hit the ground, the ground is heated by radiation and emits long-wave infrared radiation. the layer of gases does not let all of this radiation pass through and in this way the earth is kept warm
how do non biodegradable plastics harm the environment
plastics may be mistaken for food by organisms. they are unable to digest it and their bodies fill with plastics and they are no longer able to eat their own food leading to their death. some animals also get trapped in plastic rings, containers or cords, which can kill them
How is paper recycled
paper: waste paper can be mixed with water and chemicals that break it down to form a pulp. this is passed through filters that remove any glue that was stuck to it ad then treated to remove printing ink form it. this leaves clean celllose fibres which can be used to make new paper.
define and explain sustainable development
sustainable development provides for the needs of an increasing human population without harming the environment.
this takes into account the needs of the environment as well as the people. achieving a balance between progress and preservation is sustainable development
Define crop monoculture, explain 3 problems caused by it.
this is when a large area of land is used to grow only one variety of crop.
it leads to a low biodiversity as it each crop only supports a certain number of species.
it can also lead to increases in pest population as there is lots of food for them all in one area. this will reduce crop yield.
it can leave the soil deficient in certain nutrients that that particular crop needs to grow.
List 6 effects of global warming
Ice caps melt
Sea levels rise
Storms
Floods
Desertification
Extinction off species
what harm is caused by ddt
ddt does not break down but rather remains in the body of the insect. when another organism eats this insect, they get the ddt too. this ddt affects the animal it is in greatly. ddt is also non specific, which means it harms not only pests but to other living beings like birds. this causes damage to them.eg. egs of certain birds became too weak, so less birds hatched because of the ddt.
What is activated sludge
activated sludge: the liquid from the settlement tanks runs into a tank called an aeration tank. like the trickling filter bed, this contains aerobic microorganisms mainly bacteria and protoctists. oxygen is provided by bubbling air through the tank. these organisms make the sewage harmless.
State and explain how forests can be conserved
instead of cutting all the tress in a forest down, just some can be cut. this is selective felling. the remaining trees will serve their purpose as habitats and hold the soil in place. then new trees can be regrown there.
Coppicing -many deciduous trees will regrow if they are cut down to about 1 meter and left t regrow. the forest can be cut down over 12 years, creating a 12 year cycle for the trees to regrow.
forests that have never been cut down before(primary forest ) should be conserved as they contain many animals and species of organisms
education can help people realize how important it is to conserve forests and lead them to conserve forests at a domestic level.
How has modern technology helped to increase food production? Explain.
agriculture machinery like tractors and combine harvesters can cultivate more land in a shorter time.
agricultural chemicals (fertilizer) add more mineral ions like nitrate ions to soils that does not contain enough of them. this boosts plant growth and increases the area in which certain crops can be cultivated.
insecticides are used to kill pests that can reduce crop yield. herbicides ensure that no weeds are growing and the crops are not competing for nutrients.
selective breeding has allowed modern wheat to produce much more grain than it did in the past. it has also produced crops that can grow in poor soils and are that are resistant to diseases.
What is a trickling filter
trickle filters: the liquid from the settlement tanks is sprinkled all over a trickling filter bed made of small stones and clinker. there are many aerobic micro organisms living on the surface of these stones. many of these are aerobic bacteria that feed on nutrients in the sewage. protoctists feed on the bacteria. fungi feed on the soluble nutrients. these micro organisms make up an ecosystem in the trickling filter bed. the liquid is then tricked onto the surface of he stoAnes through holes in a rotating pipe. this makes sure air gets mixed in with the liquid. the liquid trickles through the stones quite slowly giving he micro organisms plenty of time to work on it. by the time the water gets to the bottom it looks clear, smells clean and contains few pathogenic organisms and can be allowed to flow into water bodies.
How have we endangered species
Explain 4 points
we have destroyed their habitats for our use. For housing, farming or factories.
we hunt animals down to the extent of extinction-for food or clothing.
we have polluted the earth. the rising temperatures are makng it hard for animals that are adapted to cold conditions to survive eg. polar bears. climae change is the cause of their extinction
we have introduced species to places that it is not native to, so they native animals have no adaptions to help it survive against these predators, leading to their extinction
Define intensive livestock production. List 4 problems caused by it
It is a farming method where large numbers of animals are grown ona. Area that would naturally support only a few.
the livestock suffers in the cramped, unclean conditions they live in. disease is easily spread among them and although antibiotics are being given, the bacteria might grow resistant. the waste from the production unit can affect waterways and land nearby
How can we conserve fish stock? List 7
Impose quotas on 1. Type of fish 2. Size of fish
Encourage farmed fish
Use captive breeding(restocking)
Limits on 1. Fishing location 2. Time
Limit methods of fishing 1. No blast fishing 2. Limit net size for fishing.
Education