AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Abiotic factors: moisture levels
Moisture level is the amount of water held in soil or air in a habitat.
Checked against the AQA 8464 specification (opens in a new tab) on .
- Point 5 of 10
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Moisture level is the amount of water held in soil or air in a habitat. It is an abiotic factor because it is non-living. Water is needed for photosynthesis, transport, and cooling in plants, and for transport, excretion, temperature control, and as a solvent in animals. In dry conditions, plants may wilt and stomata close, slowing gas exchange; in waterlogged soil, roots can be starved of oxygen and decay. They should explain how moisture affects the distribution and abundance of organisms, such as woodlice preferring damp microhabitats.
What earns the marks
- Moisture level is an abiotic factor because it is a non-living physical condition of the environment.
- Water is required by plants for photosynthesis, support, transport of minerals, and cooling by transpiration.
- Animals need water for transport, excretion, temperature regulation, and as a solvent for chemical reactions.
- Low moisture can cause wilting, stomatal closure, and reduced growth in plants; waterlogging can reduce oxygen availability for roots.
- Moisture can be measured with a soil moisture meter or by drying a soil sample to constant mass and calculating percentage water loss.
Common mistakes and how to put them right
Calling moisture a biotic factor.
Put it right: Moisture is non-living, so it is abiotic; biotic factors are living, such as predators or competitors.
Stating that animals need water as a reactant for respiration.
Put it right: Water is a product of aerobic respiration, not a reactant; animals need it for transport and excretion.
Assuming all organisms prefer wet conditions.
Put it right: Some, such as certain lichens or desert plants, are adapted to dry conditions; distribution depends on the species.
Exam tips
- Link moisture to a named process, such as transpiration or excretion, rather than just saying 'plants/animals need water'.
- When describing a measurement, state the equipment and how you would calculate a result, for example, percentage water loss from mass before and after drying.
Try the lesson
The start of the Abiotic factors: moisture levels lesson, made from checked teaching notes for this specification point.
Have a go first
Which of these is an abiotic factor that includes moisture levels?
Listen
Moisture level is the amount of water held in soil or air in a habitat. It is an abiotic factor because it is non-living. Water is needed for photosynthesis, transport, and cooling in plants, and for transport, excretion, temperature control, and as a solvent in animals. In dry conditions, plants may wilt and stomata close, slowing gas exchange; in waterlogged soil, roots can be starved of oxygen and decay. They should explain how moisture affects the distribution and abundance of organisms, such as woodlice preferring damp microhabitats. A strong answer earns marks for these points. Moisture level is an abiotic factor because it is a non-living physical condition of the environment. Water is required by plants for photosynthesis, support, transport of minerals, and cooling by transpiration. Animals need water for transport, excretion, temperature regulation, and as a solvent for chemical reactions. Low moisture can cause wilting, stomatal closure, and reduced growth in plants; waterlogging can reduce oxygen availability for roots. A common slip: calling moisture a biotic factor. Instead, moisture is non-living, so it is abiotic; biotic factors are living, such as predators or competitors. Exam tip: Link moisture to a named process, such as transpiration or excretion, rather than just saying 'plants/animals need water'.
See it
Key words
Say what each word means before you turn the card.
Moisture level
Try answering aloud or in your head before turning the card.
Abiotic factor
Try answering aloud or in your head before turning the card.
Transpiration
Try answering aloud or in your head before turning the card.
Soil moisture meter
Try answering aloud or in your head before turning the card.
See every definition
- Moisture level
- The amount of water held in soil or air in a habitat, and an abiotic factor because it is non-living.
- Abiotic factor
- A non-living physical condition of the environment, such as moisture level.
- Transpiration
- A process by which plants are cooled, one of the reasons water is required by plants.
- Soil moisture meter
- Equipment used to measure moisture, alongside drying a soil sample to constant mass and calculating percentage water loss.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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