| Feature | Biotic Factors | Abiotic Factors |
|---|---|---|
| Nature | Living or once-living | Non-living physical/chemical |
| Examples | Predation, Disease, Competition | Temperature, pH, Light, Oxygen |
| Interaction | Often density-dependent | Often density-independent |
| Role | Biological community structure | Environmental tolerance limits |
Identify the Limiting Factor: In exam scenarios, look for the variable that, when changed, causes the most significant shift in population size. This is often the 'limiting factor' for that specific ecosystem.
Distinguish Niche vs. Habitat: Remember that a habitat is the 'address' (where it lives), while the niche is the 'profession' (how it lives). Biotic and abiotic factors define the niche.
Check for Indirect Effects: A change in an abiotic factor (like temperature) often leads to a change in a biotic factor (like food availability). Always trace the full chain of cause and effect in your answers.
Precision in Terminology: Use terms like 'interspecific' and 'intraspecific' correctly. Misusing these terms is a common way to lose marks in comparative ecology questions.
Static Environment Fallacy: Students often assume abiotic factors are constant. In reality, factors like oxygen concentration in water or soil moisture fluctuate daily and seasonally.
Ignoring Microclimates: Large-scale abiotic data (like regional temperature) may not reflect the actual conditions experienced by an organism in a microhabitat, such as under a fallen log.
Confusing Correlation with Causation: Just because a species distribution matches a pH gradient doesn't mean pH is the direct cause; it might be that pH affects a specific competitor instead.
