Summary
Biotic factors are living components; abiotic factors are non-living such as light, water and temperature.
In depth
Abiotic: temperature, light, water, pH, salinity, oxygen, soil type and fire. Biotic: competition, predation, parasitism, mutualism and disease. Both limit where species can live.
Organisms have tolerance ranges for each factor, with an optimum and limits.
Interactions between factors matter: temperature affects oxygen solubility in water. Measuring abiotic variables uses probes, light meters and soil kits.
Example: pH determines which plants grow on acid or limestone soils.
Abiotic factors set the limits for life: temperature affects enzyme rates, water availability affects structure and behaviour, light determines photosynthesis, and salinity or pH affects osmoregulation. Biotic factors act through interactions with other organisms, and the two often combine: a plant stressed by drought is more susceptible to herbivores.
Tolerance curves show an optimum range with zones of stress and limits beyond which a species cannot survive (Shelford's law of tolerance). Liebig's law of the minimum says that growth is limited by the scarcest essential resource. Measuring tools include thermometers, light meters, pH probes and dissolved oxygen meters.
Example: in a stream, dissolved oxygen (abiotic) falls as water warms, which affects trout (biotic).
Frequently asked questions
What is Biotic and Abiotic Factors?
Biotic factors are living components; abiotic factors are non-living such as light, water and temperature.
Which area of biology covers Biotic and Abiotic Factors, and how advanced is it?
Biotic and Abiotic Factors is one of the 54 topics in Ecology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Limiting Factors, Producers, Climate Change Ecology.
Can you give an example of Biotic and Abiotic Factors?
Coral reefs need warm, clear, shallow water of stable salinity.
What should I learn before Biotic and Abiotic Factors?
Biotic and Abiotic Factors is a Beginner topic, so no earlier topic is required. Other Beginner topics in Ecology that pair well with it include Ecology, Ecosystem, Habitat and Niche.
What topics are related to Biotic and Abiotic Factors?
The closest topics to Biotic and Abiotic Factors are Limiting Factors, Producers, Climate Change Ecology, Competition. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Biotic and Abiotic Factors?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Biotic and Abiotic Factors. To practise the whole of Ecology, use the Ecology quiz.
How is Biotic and Abiotic Factors different from Limiting Factors?
Biotic and Abiotic Factors: Biotic factors are living components; abiotic factors are non-living such as light, water and temperature. Limiting Factors: Resources or conditions that restrict population growth, either density-dependent or density-independent. Read both side by side and note what each one explains.
How should I study Biotic and Abiotic Factors step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Limiting Factors and explain the difference aloud. Finally, take the Ecology quiz and come back to this page for any question you miss.