Botany · Ch 6 — Principles of Ecology
Ecological Factors
Ecological Factors
Every organism exists inside a surrounding environment made up of physical, chemical and biological components. The moment one of those surrounding components actually affects the life of the organism — its growth, survival or reproduction — it earns the label ecological factor (or environmental factor). Taken all together, these factors can first be split into two broad categories: biotic factors (living — other organisms) and abiotic factors (non-living — soil, climate, physical terrain). For teaching purposes, ecologists further group all ecological factors into four meaningful classes: (i) climatic factors (light, temperature, water, wind, fire), (ii) edaphic factors (soil properties), (iii) topographic factors (surface relief — latitude, altitude, slope, aspect), and (iv) biotic factors (the effects of other living organisms). Every plant, at any moment, is simultaneously being shaped by factors from all four classes at once — which is why the diagram of a single plant surrounded by sunlight, soil, …
What this figure shows. A composite diagram placing a plant at the centre and radiating out the four factor classes around it — climatic factors (sunlight, precipitation, wind, carbon dioxide and water vapour), edaphic factors (soil slope, soil water, soil air, minerals, physical nature of the soil), and biotic factors (birds, insects, grazing animals, rodents, man, plant pathogens, epiphytes) — showing how a single plant sits at the intersection of all these inf …