The idea
Every organism lives inside a set of limits. Too cold, too dry, too salty, too dark — and it cannot survive there. Those limits come from abiotic factors: the non-living conditions of a place.
Factors worth measuring
| Factor | Measured with | Why it matters |
|---|---|---|
| Temperature | Thermometer or probe | Sets the rate of every biological reaction |
| Light intensity | Light meter (or a phone app) | Drives photosynthesis |
| Soil moisture | Moisture probe, or mass before and after drying | Limits which plants take hold |
| pH | Test strips or a pH probe | Most freshwater life needs 6.5–8.2 |
| Dissolved oxygen | DO probe or a test kit | Cold, moving water holds more |
Range of tolerance
Plot the survival of a species against any abiotic factor and you tend to get the same shape: a comfortable middle, a stressful zone on each side, and lethal limits at the edges. That middle is the optimal range.
Biotic factors are the other organisms
Competition, predation, disease, cooperation. A sugar maple seedling is not only fighting the cold — it is also fighting for light with every other seedling around it.
You will measure some of these yourself in Measuring Abiotic Factors.
Curriculum connection
B2.1
investigate interactions between the biosphere, hydrosphere, lithosphere, and atmosphere, and explain why these interactions are important for ecosystem sustainability
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B2.4
investigate factors and processes, including biodiversity, air and water quality, soil health, and succession, and explain how they contribute to ecosystem sustainability
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