The Influence of Human Activity on the Environment :The Influence of Human Activity on the Environment More free powerpoints at http://www.worldofteaching.com


Improvements in agriculture health and medicine have produced a dramatic rise in the human population :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. :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 :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 :Sulphur dioxide will dissolve in rain producing Acid Rain Acid rain damages trees and pollutes rivers and lakes.


Acid rain causes erosion of buildingsand statues particularly if they are made of limestone :Acid rain causes erosion of buildingsand statues particularly if they are made of limestone


Deforestation :Deforestation In may countries people are chopping down forests to provide timber or space for agriculture for the growing population


This causes several problems :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 :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 :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


Slide 12: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 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 :In the 1960s, DDT in the food chain threatened bird populations.Many birds of prey came close to extinction


What can we Do? :What can we Do?


Organic Farming? :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 :Use farmyard manure as a fertiliser and set aside land for growth of wild plants


Biological Control of Pests :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 :Develop alternative energy sources Conserve our rapidly diminishing fossil fuel reserves by using solar power or wind power


Benefits of conserving endangered species :Benefits of conserving endangered species Ecotourism Agricultural benefits Species indicators Maintaining diversity in gene pool


Slide 22:WHAT ELSE?????????