In order to survive and reproduce, organisms require materials from their surroundings and from the other organisms living there.
Plants often compete with each other for light and space, and for water and nutrients from the soil
Animals compete with each other mates, food and territory
Organisms and microorganisms have features (adaptations) which enabled them to survive in the conditions in which they normally live.
Some organisms live in environments which are very extreme. They are called extremophiles and they may be tolerant to high
levels of salt, high temperatures or high pressures.
They are adapted to live in conditions where enzymes won't usually work because they would denature.
Animal adaptations
Animals may be adapted for survival in dry and artic conditions by means of:
Changes to surface area (bigger animals have a smaller surface area compared to their volume which means that they can conserve
energy more easily but it is also more difficult to cool down)
Thickness of insulating coat (in cold climates animals have thick fur and fat under the skin (blubber) to keep them warm)
Amount of body fat
Camouflage (some animals in the arctic (e.g arctic fox & hare) are white in the winter and brown in summer)
Plant adaptations
Plants can be adapted to survive in dry environments by means of:
Having small or waxy leaves
water storage tissues
extensive root systems
Having a swollen stem to store water
Environmental change
Changes in the environment affect the distribution of living organisms
If the environment changes the organism may not be able to live there any more
Non-living factors which may change could include: temperature, rainfall, light and oxygen levels
Living factors which might change include: new predators or diseases, new
plants which could provide new food or habitats
Living organisms can be used as indicators of pollution:
Lichen can be used as air pollution indicators, particularly for sulfur dioxide. The
more species of lichen growing, the cleaner the air.
Invertebrate animals can be used as water pollution indicators (the wider the range of them the
cleaner the water) and are also used as indicator of the concentration of dissolved oxygen in
water
Lichen and invertebrate animals are both examples of indicator species
Environmental change can also be measured using non-living indicators such as oxygen levels, temperature and rainfall.
This is done using equipment such as rain gauges,
thermometers, PH and oxygen sensors and data loggers