The transfer of food energy from the source in plants through a series of organisms with repeated eating and being eaten is referred to or called as food chain.
The green plants are the autotrophs or the producer of the ecosystem. With the help of chlorophyll, and by using CO2 and H2O from nature in presence of sunlight the plants can prepare their own food known as carbohydrates. The process is known as photosynthesis.
That’s why plants are called autotrophs (auto-self; troph-to nourish) Thus, plants are the first step in a food chain.
The heterotrophs (hetero= other; troph = to nourish) are the organisms who depends on the autotrophs for food and energy. Heterotrophs are two types – Herbivores and Carnivores.
- Herbivores are the herb/plant eaters. They can only eat the green plants/autotrophs. Ex. Grasshoppers, Rabbits, Goats etc.
- Carnivores are the meat eaters in an ecosystem. They cannot have the ability to eat herbs. For example, Frogs, Snakes, Hawks, Lions, Tigers.
Thus, in an ecosystem a chain like structure is found based on “-to eat and being eaten“ scheme, which is also called “Pray- Predator relationship” in an ecosystem.
Types of Food Chain
Two types of food chains are observed in different ecosystems, known as Grazing Food Chain and Detritus Food chains.
1. Grazing Food Chain
It is recognized by the starting level organisms of a food chain. They are the living green plants. Then if we see the examples, in a grassland ecosystem the chain will be starting with Greengrass, then Grasshoppers, then Frogs then Snakes then Hawks as shown in the above figure.
2. Detritus Food Chain
Here the starting point is dead plants or animals. This type of Food chain does not depend on the sunlight. Ex- Dead plants and animals, Scavengers, Micro organism
This should be noted that the Grazing and Detritus Food Chain perform independent to each other but different parts of a single ecosystem. More energy is transferred in a grazing food chain than in a detritus one. Combinedly the grazing and the detritus Food chain complete the nutrient cycle in an ecosystem.