Bitesize has changed! We're updating subjects as fast as we can. Visit our new site to find Bitesize guides and clips - and tell us what you think!

Did you know?

We also have Bitesize study guides covering many subjects at National 4 and National 5 on our Knowledge & Learning BETA website.

Home > Biology > The biosphere > Investigating an ecosystem


Investigating an ecosystem

Abiotic factors

Abiotic factors are non-living conditions which can influence where plants or animals live.

Examples of abiotic factors include:

  • temperature
  • light intensity
  • moisture content of soil
  • pH of the environment

Measuring Light Intensity

Light meters can be used to measure light intensity. The meter is held at the soil surface and pointed in the direction of the maximum light intensity, then the meter is read. Errors can be made when measuring light intensity by accidentally shading the light meter. Results can be made more reliable by taking many samples.

Measuring Moisture Content of Soil

Soil     meter with probe inserted into soil of houseplant to measure moisture content

Soil moisture and soil pH meters are also available - both are used by simply pushing the probe into the soil and reading themeter.

Errors can be made when measuring abiotic factors when the soil moisture or pH meter probes are not cleaned between readings. As always the results can be made more reliable by taking many samples.

Factors affecting the distribution of organisms

You should be able to think of one or two more examples of organisms which live in particular place, and explain what factors influence this.

Here are some examples:


  • The more light available, the more daisy plants will be present.
  • This is because daisies need light energy from the sun to make their own food (photosynthesise).


  • Grasses are found in the full sunlight of a field rather than in shady woodland.
  • This is because grasses need lots of light energy from the sun to photosynthesise.


A picture of Mia Cadaver

Tombstone Timeout

Test out your knowledge of biology with Mia Cadaver's biology game - it's serious fun!

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.