Abiotic & Biotic Factors (Edexcel GCSE Biology): Revision Note

Abiotic & Biotic Factors

• The environment in which communities of plants and animals live is changing all the time

• These changes are caused by abiotic (non-living) and biotic (living) factors

• These factors affect communities in different ways, for example:

  • For some species, certain factors may cause their population size to increase, whereas for other species their population size may decrease

  • For some species, certain factors may cause the distribution of their populations (i.e. where they live) to change

Abiotic factors

• In Biology, ‘abiotic’ means non-living

• An abiotic factor is a non-living factor within an environment such as temperature, light intensity and water availability

• The table below explains how these abiotic factors may affect a community of organisms

  • One abiotic factor not included in this table is the presence and levels of pollutants, which can change the size and distribution of populations of certain species

  • For example, lichen are very sensitive to air pollution and are not able to grow if the concentration of sulphur dioxide (an air pollutant) gets above a certain level

Abiotic Factors that Affect Communities Table

Biotic factors

• In Biology, ‘biotic’ means living

• A biotic factor is a living factor in the environment such as competition, predation and disease

Biotic Factors that Affect Communities Table