In ecosystem The producer-consumer arrangement is one kind of structure which is known as trophic structure (trophic food) and each food (nutritional) level in the food chain is called trophic level or energy level.
- Producers or plants which constitute the first trophic level.
- Herbivores that constitute the second trophic level.
- Carnivores that feed on herbivores constitute the third trophic level.
- Decomposers form the last or detritus trophic level.
Example of trophic levels
Green plant → Herbivores → Carnivores → Top carnivore → Decomposer
Tropic Level T1 T2 T3 T4 T5
Other types of food chain
1. Grazing food chain - The consumers which consume the living plant parts as their food or energy source constitute the grazing food chain. It is the most common food chain in majority of the ecosystems,
Example -
Grass → Grasshopper → Birds → Hawks
2. Detritus food chain - Other animals and lower plants (bacteria and fungi) which get their energy (or food) from dead organic parts constitute the detritus food chain. Detritus food chain is the shortest.
example - Dead organic matter → Earthworms → Frog → Snakes → Hawks
3. Parasitic food chain - Chain goes from large to small parasitic organisms.
Limited Number of Trophic Levels in Food Chain
A large portion of energy is lost at each trophic level in a food chain. This results in lesser amount of energy being passed on by the organisms of one trophic level to the next trophic level. As the number of trophic levels in a food chain increases, the organisms at the extreme right side of the food chain receive least amount of energy. This limits the number of trophic levels or steps in a food chain to five or six.
Organisms of one trophic level have the same food habit but may have several food resources like leaves, seeds, fleshy, fruits, grasses, etc. Thus, a group of species belonging to a trophic level which is consumes a common resource base is known as guild, example- nectar feeding birds, grazing animals and frugivorous animals. Thus and ecosystem has a limited number of trophic levels because:
- There is loss of food energy at each number.
- Food is not completely utilized by the organisms of a trophic level.
- A large number of energy is used in respiration.
No comments:
Post a Comment