AQA Core Biology 1b (ii) - Evolution and Environment.
Human Impact on the Environment.
We have an impact on the world around us, and the more humans there are, the bigger the impact.
There are Six Billion People in the World...
1) The population of the world is currently rising very quickly, and it is not slowing down.
2) This is mostly due to modern medicine and farming methods, which have reduced the number of people dying from disease and hunger.
3) This is great for all the humans, but it means we are having a bigger effect on the environment we live in.
...With Increasing Demands on the Environment.
When Earth population was much smaller, the effects of human activity was small and local. Nowadays though, our actions have a far more widespread effect.
1) Our rapidly increasing population puts pressure on the environment, as we take the resources we need to survive.
2) But people around the world are also demanding a higher standard of living (and so demand luxuries to make life more comfortable, care, computers, etc.). So we use more raw materials (e.g. oil to make plastics), but we also use more energy for the manufacturing processes. This means we're taking more and more resources from the environment more and more quickly.
3) Unfortunately a lot of raw materials are being used up quicker then they are being replaced. So if we carry on like we are one day we are going to run out.
We're Also Producing More Waste.
As we make more and more things, we produce more and more waste. And unless this waste is properly handled, more harmful pollution will be caused. This effects water, land and air.
Water: Sewage and toxic chemicals from industry pollute lakes, rivers and oceans, affecting the plants and animals that rely on them for survival (including humans). And the chemicals that are used on land (e.g. fertilizers) can be washed into the water.
Land: We use toxic chemicals for farming (e.g. pesticides and herbicides). We also bury nuclear waste underground, and we dump a lot of household waste in landfill sites.
Air: Smoke and gases released into the atmosphere can pollute the air. For example sulphur dioxide can cause acid rain.
More people Means Less Land for Plants and Other Animals.
Humans who also reduce the amount of land and resources available to animals and plants. The four main human activities that do this are:
3) Dumping Waste.
The Greenhouse Effect.
The greenhouse effect is always in the news. We need it, since it makes Earth a suitable temperature for living on. But it is starting to trap more heat then necessary.
Carbon Dioxide and Methane Trap Heat from the Sun.
1) The temperature of the Earth is a balance between the heat it gets from…