Each link or level in a food chain has a name. These names help us to know what the organism eats and what is its energy contribution in the food chain.
Producers: The organisms that can produce their own food or energy are called the producers. They are not dependent on any other organism for food. All plants are producers.
Consumers: The organisms that depend on other plants and animals for food or energy are consumers. They cannot make their food. All animals, including humans are the consumers.
Decomposers: The organisms that depend on the decaying plants and dead animals are called the decomposers.
Green plants are the producers in a food chain. They can transfer the sun's energy into food through photosynthesis.
Producers are usually the first part of a food chain.
Herbivores
The consumers come next. Consumers are divided into two groups. First are the animals that consume only plants called herbivores. These herbivores usually form the second part of the food chain and are called first-level consumers.After herbivores, the animals that eat other animals come next. These animals are either carnivores or omnivores.
Carnivores and Omnivores
Omnivores are animals that eat both plants and animals. Carnivores are the animals that eat only other animals. Both these groups of animals are called the second level consumers and then the third level consumers, and so on.
Decomposers
The last members of the food chain are the plants and animals that feed on dead animals and plants. They are called decomposers. Decomposers help to return nutrients back into the soil. These nutrients will be used later by the plants in the food chain. Insects, snails, mushrooms, bacteria, etc., are examples decomposers.
Energy is lost at each level
As the food chain gets longer, there is a decrease in the level of energy that passes from one animal to another.
Plants are the only organisms that make their own food. Plants introduce the energy in the food chain. All the others are consumers of the energy.
More organisms are required at lower levels on the food chain. Because more of them should supply the required energy to animals that are higher on the food chain. It means, the energy available decreases at each link, the number of animals also decreases as we move up a food chain.
Grass → Deer→ Lion
In the example given above, there is more energy in the grass than the deer and more energy in the deer than the lions. The deer and lion use up energy doing running, hunting, and breathing.
An energy pyramid is a graphical representation to show the energy used up at each level in a given ecosystem.