Producers are organisms like the green plants which manufacture their own food in the form of organic nutrients from inorganic substances abiotic substances. Green plants produce food by the process of photosynthesis, the sun provides energy - this solar energy is converted into chemical energy in the green part of the plant - the chloroplasts. The chloroplasts contain the green pigment chlorophyll which traps energy from the sun for the process of photosynthesis. Producers are also known as autotrophs. Autotrophs are the basic of any biotic factor in an ecosystem. In a terrestrial ecosystem the producers or autotrophs are rooted green plants; on aquatic ecosystem, producers or autotrophs are floating plants called phytoplankton and shallow water rooted plants known as macrophytes.
Consumers are the organisms that cannot make their own food from inorganic compounds. The consumers are dependent on autotrophic organisms or producers or other primary consumer or heterotrophic organisms in an ecosystem. The consumers are subdivided into herbivores, carnivores and omnivores according to their diet. In the trophic level they are known as primary consumers, secondary consumers and tertiary consumers.
- Herbivores are organisms that feed on plants. They are known as primary consumers. Example: Cows, giraffes, elephants, etc.
- Carnivores are animals that feed on herbivores and are meat eater. They are known as secondary consumers. Example: Crow, snakes, etc.
- Tertiary consumers are animals that feed on secondary consumers and in turn are not preyed upon by any other organism. Example: Lion, tiger, etc.
- Omnivores are organisms that feed both on plants and on animal matter, these organisms may be primary, secondary and tertiary consumers simultaneously. Example: Human being.
Decomposers are usually saprophytes. These are saprophytic organisms like bacteria and fungi that obtain their nutrition by decomposing dead matter of other organisms. These organisms break down the organic matter of the producers and consumers into inorganic material that are released into the soil or water which are then reused by the producers.