- organisms increase their chances of survival by responding to changes in their external environment. animals and plants respond in different ways:

for example, animals can move away from harmful environments such as places which are too hot or too cold.
plants cannot actually move themselves, but they can change the way they grow in an attempt to find more favourable environmental conditions. e.g. seedlings growing in dark conditions can rapidly develop very long, thin stems to increase their chances of finding light.

- organisms also respond to changes in their internal environment to make sure that the conditions are always optimal for their metabolism (all the chemical reactions that go on inside them).
- any change in the internal or external environment, e.g. a change in temperature, light intensity or pressure is called a stimulus.

	Criado por izzy smith mais de 7 anos atrás

notes on survival and response for the aqa biology spec.