The living organisms are influenced by a large number of environmental factors. These environmental factors are known as ecological factors or eco-factors.
These factors may be biotic (living) or abiotic (non-living). All the environmental factors bring marked distributional, structural and functional changes in living organisms. To live, grow and carry out all its activities, the organisms require a harmonious relationship with their environment. The differences in vegetation of a desert and a rain forest, plants in a pond and grassland, animals in tropical countries and cold countries, clearly indicate the role of environmental factors in the distribution and survival of organisms in different eco-systems.
Major ecological factors can be classified into:
(a) light (b) temperature (c) rainfall (d) wind (e) humidity (f) pH. A variation in one or more of these factors affects the distribution and lifestyle of organisms.
(a) Altitude (b) slope and direction of mountain chain and valleys.
Structure, formation and characteristics of different types of soils.
These are derived from the interactions between different species of living organisims (intra-specific as well as inter-specific).