Abiotic factors

Ecology · Adaptations, interdependence and competition · note 2 of 4

Spec 4.7.1.2Download all Adaptations, interdependence and competition notes (PDF)Download all notes (PDF)6 pages

Abiotic factorsSpec 4.7.1.2

In short

Abiotic factors are the non-living factors that can affect a community. They include light intensity, temperature, moisture levels, soil pH and mineral content, wind intensity and direction, carbon dioxide levels for plants and oxygen levels for aquatic animals. A change affects the organisms that depend on that factor, and then the species that feed on or depend on those organisms.

Abiotic (non-living) factors can affect a community. If one of them changes, the organisms that depend on it are affected, and so are the species that feed on or depend on those organisms.

Abiotic factors and how a change might affect organisms
Abiotic factor	How a change could affect organisms
Light intensity	Less light means plants photosynthesise more slowly and grow less, so there is less food for the animals that eat them
Temperature	Changes the rate of enzyme-controlled reactions, so growth and reproduction speed up or slow down. Too hot or too cold and organisms may die or move away
Moisture levels	Plants and animals need water to survive. In drier conditions, fewer organisms can live there
Soil pH and mineral content	Plants only grow well in a suitable pH and need mineral ions for healthy growth. Poor soil means fewer plants
Wind intensity and direction	Strong wind can damage plants and increases water loss from them. It also affects how easily animals move and feed
Carbon dioxide levels for plants	Carbon dioxide is needed for photosynthesis. Lower levels slow the growth of plants
Oxygen levels for aquatic animals	Aquatic animals need oxygen for respiration. If levels fall, fewer animals can survive in the water

To explain the effect of a change, link three steps: what changed, how it affects the organism, and what happens to the community.

Exam tip:

Always finish the chain. Saying 'less light' is not enough. Say that there is less photosynthesis, so plants grow less and fewer herbivores can be supported.

Maths skill:

Questions often give a table or graph of an abiotic factor against the number of organisms. State where the number is highest or lowest, and quote values from the data.

Written and checked against the AQA GCSE Combined Science (8464) specification · Updated October 2026

Frequently asked questions

What is the difference between a population and a community?

A population is all the organisms of one species living in the same area, such as all the frogs in a pond. A community is all the populations of the different species living in that area, including the plants, animals and microorganisms. A community together with the non-living parts of its environment makes an ecosystem.

What is interdependence in ecology?

Interdependence means that within a community each species depends on other species for food, shelter, pollination, seed dispersal and so on. If one species is removed it can affect the whole community. For example, if a plant pollinated by one insect is removed, that insect loses its food, and so do the animals that eat it.

What is the difference between abiotic and biotic factors?

Abiotic factors are non-living parts of the environment, such as light intensity, temperature, moisture levels, soil pH and mineral content, wind, carbon dioxide and oxygen levels. Biotic factors are living, such as the availability of food, new predators, new pathogens and one species outcompeting another. A change in either kind can affect a whole community.

All 4 questions on Adaptations, interdependence and competition