Ecology the study of interrelationships of organisms

Ecology is derived from two words ECO or oikos which means house or place to live in and logos which means study of. Therefore ecology is the study of the interrelationships of organisms to each other and to their environment. To bring out this let us look at this illustration. For a cabbage to grow it requires light, rainfall among other factors. Worms rely on cabbages for survival. Therefore there exist a relationship between a cabbage, worm and the weather.

Ecology is subdivided in to two main branches, that is, synecology and autecology.

Synecology is the study of different species living and interacting in the same ecosystem e.g. wild beasts, warthogs, zebras and termites living in the same ecosystem.

Terms used in ecology

Some of the terms that are used in ecology include: - Biosphere, habitat, niche, population, community, ecosystem and carrying capacity.

Biosphere (Ecosphere) - It is the part of the earth and atmosphere inhabited by living organisms.


This is the physical location that an organism lives in with a particular set of conditions. Examples are a fish living in a pond, a grasshopper in a field, and monkeys in a forest. The pond, the field and forest are habitats. Some habitats are formed of land therefore referred to as terrestrial or can be formed of water therefore referred to as aquatic.


Describes where an organism lives and how it lives. This includes the position that an organism occupies in a habitat such as physical space and the role the organism plays in the habitat in terms of feeding relationships and interactions with other species.

For example, buffaloes, zebras and egrets can live in the same habitat but each organism is playing a different role. Giraffes are browsers, zebras, buffaloes and gazelles are grazers, while the egrets are commensals.


-Refers to the total number of a particular species of organisms living in a particular habitat at a particular time.

For example: The number of flamingos at Lake Nakuru is approximately 250,000.


-An ecosystem is a unit comprised of several habitats and their communities of organisms living together in a self sustaining environment. Play the video clip below to see an example of an ecosystem.

Carrying capacity

This is the maximum population of a species that a particular habitat can support indefinitely under a given set of environmental conditions without depletion of resources in that habitat.

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