Biotic factors are the living components—that is, the plants, animals and other organisms—that constitute an ecosystem. These factors are dependent on one another for sustenance. They interact with the abiotic factors in which they subsist, such as air, water, temperature and soil, thereby functioning together as a unit. Biotic factors are variously classified as primary producers, primary consumers, secondary consumers, tertiary consumers, and detritivores or decomposers, depending on their respective feeding positions within an ecosystem.
Primary producers are also known as autotrophs, or self-feeders, as they make their own food by using abiotic ingredients such as sunlight. They provide food for other living things in an ecosystem either directly or indirectly. Primary producers are mainly green plants, algae or other organisms that can create energy from the sun through photosynthesis. Some primary producers, such as specialized bacteria, can create organic nutrients out of inorganic compounds in the absence of sunlight by chemosynthesis.
Primary consumers are living things that consume primary producers. Also known as herbivores, they obtain energy from a diet of plants. An example of a primary consumer is an orangutan, which thrives on grass, figs and leaves.
Secondary consumers derive energy from other consumers. They are either carnivores (meat-eating animals) or omnivores (animals that feed on both plants and animals). Carnivores hunt and consume other animals for their survival; for this reason, they are known as predators. Wolves, bobcats and cougars are carnivores whose sharp claws and powerful jaws help them capture and eat animals such as deer. Grizzly bears and birds such as crows and woodpeckers are examples of omnivores. Grizzly bears eat grasses, roots, fish and small mammals.
Tertiary consumers are carnivores that feed on other carnivores. These animals are at the top of the ecosystem. An owl, to take one example, is a tertiary consumer that eats snakes.
Detritivores or Decomposers
Detritivores or decomposers play a vital role in maintaining the ecological balance. They ensure the survival of plants, the primary producers within an ecosystem, by recycling nutrients back to the plants. Earthworms, fungi and bacteria are examples of detritivores that break down dead material and waste into basic ingredients and release inorganic elements into the environment by decomposition. These ingredients can be recycled through the system.