Factors That Affect Communities (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Revision Note
Exam code: 8465
Abiotic Factors
In Biology, ‘abiotic’ means non-living. An abiotic factor is a non-living factor
Some abiotic factors which can affect a community are shown in the table below:
Abiotic factors that affect a community
Effects of abiotic factors
You should be able to extract and interpret information from charts, graphs and tables relating to the effect of abiotic factors on organisms within a community
Worked Example
Example exam question
Plants of the same species were grown in tanks with different CO2 levels. Their height was measured after 3 weeks and an average taken:
Graph showing the effect of CO2 concentration on plant height
What conclusion can you draw from this graph about the effect of CO2 concentration on plant growth rate? Explain your answer.
Example exam answer
As CO2 concentration increases, average plant height also increases. For example, at 5% CO2, average plant height was 10cm, but at 30% CO2, average plant height was 60cm. This shows that the higher the CO2 concentration, the greater the plant growth rate. This is because CO2 is used by plants for photosynthesis, which allows the plant to produce glucose for energy to grow.
Examiner Tips and Tricks
When answering questions that refer to a chart, graph or table, remember to reference specific figures from the data to support your answer, as seen in the example above.
Biotic Factors
In Biology, ‘biotic’ means living. A biotic factor is a living factor
Biotic factors that can affect a community table
Effects of biotic factors
You should be able to extract and interpret information from charts, graphs and tables relating to the effect of biotic factors on organisms within a community
Worked Example
A study recorded the number of red and grey squirrels in a particular woodland habitat for 20 years. Grey squirrels were introduced to the habitat in year 6 of the study.
Graph showing the relationship between a grey squirrel population and a red squirrel population over time
What conclusion can you draw from this graph about the effect of introducing grey squirrels to a habitat that is occupied by red squirrels? Explain why this might have occurred.
Example exam answer
As the number of grey squirrels increases, the number of red squirrels decreases. This might have occurred because the two squirrel species are competing for one or more of the same resources. Grey squirrels are better adapted to use these resources and have outcompeted the red squirrels until eventually there are too few red squirrels left to breed successfully and there are none left in the habitat.
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