Measuring Abiotic Factors (SQA National 5 Biology): Revision Note

Exam code: X807 75

Naomi Holyoak

Last updated

Methods for measuring abiotic factors

  • When investigating the impact of an abiotic factor on species distribution, the relevant factor should be measured at all study sites

    • Abiotic factors can be measured using specialised equipment and techniques

  • Care should be taken during measurements to ensure that sources of error are minimised

Abiotic factor

How it is measured

Minimising error

Light intensity

Electronic light meter

Direct the meter towards the exact region being assessed

Do not shade the meter with the body and avoid creating reflected light

Ensure that the values have stabilised before recording

Ensure that all readings are taken at the same time of day / year

Soil moisture

Weigh a moist soil sample, dry it, then reweigh; the mass difference gives water content

Electronic moisture meter

Ensure that sample is taken at a standard depth

Ensure that any probes are cleaned between uses

Ensure that the values have stabilised before recording

pH

Indicator solution mixed with a soil or water sample

Electronic pH meter

Keep soil : water ratio constant

Stir/settle for the same length of time before reading

Take multiple soil samples from each site, mix, and test to reduce local variation

Temperature

Thermometer

Electronic temperature probe

Ensure that the values have stabilised before recording

Avoid direct sunlight on the sensor for air readings

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Naomi Holyoak

Author: Naomi Holyoak

Expertise: Biology Content Creator

Naomi graduated from the University of Oxford with a degree in Biological Sciences. She has 8 years of classroom experience teaching Key Stage 3 up to A-Level biology, and is currently a tutor and A-Level examiner. Naomi especially enjoys creating resources that enable students to build a solid understanding of subject content, while also connecting their knowledge with biology’s exciting, real-world applications.