Environmental change

Animals and plants are exposed to environmental change. These changes may be caused by living

factors, such as a change in a predator, a food source or a competitor. Environmental changes may

also be caused by non-living factors, such as a change in temperature or rainfall.

Effects of environmental change

Changes in the environment affect the distribution and behaviour of living organisms. For example,

humans have been cutting down trees for thousands of years. We do this to clear land for farming and

building, and for wood to use as a fuel or building material. This deforestation can have local effects,

such as a reduction in food and shelter for animals. It can also have more widespread effects, such as

changes in rainfall and temperature. These changes may change the distribution of bird species, for

example.

The world's forests 8000 BC

The world's forests 2000CE

Human activities can pollute the air and water. The presence or absence of certain living

organisms acts as an indicator of the amount of pollution.

Air pollution

The most common source of air pollution is the combustion of fossil fuels. This usually happens in

vehicle engines and power stations. Sulfur dioxide is released if the fuel contains sulfur compounds.

This gas contributes to acid rain. Lichens can be used as air pollution indicators, especially of the

concentration of sulfur dioxide in the atmosphere.

Factories can cause air pollution

Lichens are plants that grow in exposed places such as rocks or tree bark. They need to be very good

at absorbing water and nutrients to grow there. Rainwater contains just enough nutrients to keep them

alive. Air pollutants dissolved in rainwater, especially sulfur dioxide, can damage lichens, and prevent

them from growing. This makes lichens natural indicators of air pollution. For example:

bushy lichens need really clean air

leafy lichens can survive a small amount of air pollution

crusty lichens can survive in more polluted air.

In places where no lichens are growing, it is often a sign that the air is heavily polluted with sulfur

dioxide.

Water pollution

Oil spills cause a lot of harm to the environment, both at sea and on land

Water pollution is caused by the discharge of harmful substances into rivers, lakes and seas. Many

aquatic invertebrate animals cannot survive in polluted water, so their presence or absence indicates

the extent to which a body of water is polluted.

Climate change is a huge issue. It can mean different weather patterns. Hurricanes can become larger

and can occur at abnormal places like above or below 30 degrees lat. Drought and floods can occur at

abnormal places. Entire ecosystems can alter, like deserts forming or tundras turning to deciduous

forests... The very continents can reshape. There are a million things that can happen. Most of these

things are related to global warming. Global cooling can have similar and different results.