THE INFLUENCE OF HUMAN ACTIVIES ON THE ENVIRONMENT

The Influence of Human Activity on the Environment
Improvements in agriculture health and medicine have produced a dramatic rise in the human population
This increase in population size leads to an increase in pollution and higher demand for the world’s resources


Humans are using up the earth’s resources, including fossil fuels.

Burning fossil fuels in cars and power stations produces carbon dioxide, sulphur dioxide and other greenhouse gases
carbon dioxide traps heat in the atmosphere and causes the temperature of the earth to rise.

This leads to disruption of the weather patterns eg drought, floods

Some weeds may thrive on the extra carbon dioxide while other plants are killed
Sulphur dioxide will dissolve in rain producing Acid Rain
Acid rain damages trees and pollutes rivers and lakes.
Acid rain causes erosion of buildings
and statues particularly if they are made of limestone

Deforestation
In may countries people are chopping down forests to provide timber or space for agriculture for the growing population
This causes several problems

Burning the timber increases the level of carbon dioxide in the air
Less trees means less carbon dioxide absorbed for photosynthesis
Soil is eroded as it is exposed to the wind and rain
Less water is transpired into the atmosphere
Many animal and plant habitats are destroyed causing extinction of species
Intensive Farming
Farming has become more intensive to provide a higher % yield from land
Many people regard intensive farming of animals to be cruel
In order to produce more food from the land farmers have to use more fertilisers and pesticides
Problems with Fertilisers
Fertilisers enable farmers to grow more food as they are replacing the nutrients removed from the soil by plants
However, if too much fertiliser is added and it then rains, the fertiliser finds its way into rivers and lakes
This causes the water plants to grow and as there is competition for light, some will die
Bacteria decay the dead plants and in so doing use up oxygen from the water
This means the fish suffocate and die
This process is called Eutrophication
Raw sewage pumped into rivers has the same effect
Pesticides
Pesticides kill insects that will damage crops
They also kill harmless insects or can get washed into rivers and pollute the water
They may even end up in the food chain
In the 1960s, DDT in the food chain threatened bird populations.
Many birds of prey came close to extinction
What can we Do?
Organic Farming?
This produces less food and is more expensive but it does not produce the pollution problems of intensive farming
Use farmyard manure as a fertiliser and set aside land for growth of wild plants
Biological Control of Pests
This means using natural predators to eat pests instead of pesticides
It does not have harmful effects
Develop alternative energy sources
Conserve our rapidly diminishing fossil fuel reserves by using solar power or wind power
Benefits of conserving endangered species
Ecotourism

Agricultural benefits

Species indicators

Maintaining diversity in gene pool
WHAT ELSE?????????
This powerpoint was kindly donated to www.worldofteaching.com




http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.