Energy is the capacity to work. Energy exists in two forms such as potential and kinetic. Potential energy is the energy at rest (stored energy). Kinetic energy is the energy of motion (free energy).
The source of required by all living organism is the chemical energy of their food. The chemical energy is obtained by the conversion of radiant energy of sun.
Energy flow in Ecosystem:
Living organism can use energy in several forms – radiant and fixed energy. Radiant energy is in the form of light. Fixed energy is potential chemical energy found in various organic substances which can be broken down to release their energy content.
All energy forms the sun, fixed by the plants during photosynthesis. It does three things such as-
- Be stored as chemical energy in plant or animal materials.
- Be passed through the ecosystem along food chains arid food web.
- Escape from the system as outputs of material or heat energy.
When light, energy fails on green plants a part of it transformed into chemical energy and stored in various organic products with plants. When the herbivores consume plants a food and convert chemical energy into kinetic energy. Herbivores are consumed by carnivores of the first order, further degradation will occur. When primary carnivores are consumed by top carnivores again energy will be degraded.
The producers and consumers in ecosystem can be arranged into several groups, each known as tropic level (feeding level). in any ecosystem , producers represent the first , tropic level, herbivores represent the second tropic level , primary carnivores represent the third tropic level and top carnivores represent the last level.
A food chain is an ecosystem is a chain of organisms through which one organism secures food by eating another organism. Herbivores gain energy by eating plants; carnivores in turn gain energy by consuming animals and the decomposers act upon the organic matter of dead herbivores and carnivores and derive energy. Thus food from one tropic level reaches to the other trophy level and in this way a chain is established. This is known as food chain.
Principles of energy flow in a food chain:
- Passage of energy along a food is unidirectional and non-cycle.
- The chemical energy available for life process constantly decreases through the food chain.
- Precisely the food chains begin with plants and end with animals.
Types of food chains:
- Grazing food chain
- Parasitic food chain and
- Saprophytic or detritus food chain
Grazing food chain:
This pattern of food chain is very common. It starts from plants and goes from smaller to larger grazing animals, cow or goat or rabbit. These are herbivores since plants form their sole diet and by eating them they gain energy. In the same way predating animals draw energy by consuming other animals. At every step in a grazing food chain significant amount of organic matter is passed by the process like death decay and excretion of I by organism to the second type of food chain called the detritus food chain.
1. Autotrophy – 2.Herbivores – 3.Primary carnivores – 4.Secondary carnivores etc.
The classification of grazing food chain:
Terrestrial food chain:
Plant (Producer consumer) – Hare (Primary Consumer) – Fox (Secondary Consumer)
Plant (Producer consumer) – Deer (Primary Consumer) – Tiger (Secondary Consumer)
Aquatic food chain:
Phytoplankton – Insect – Fish – Man
Parasitic food chain:
This food chain is executed through parasites and scavengers. It is not as predominating as the other two food chains. However, some of the parasitic food chain may be complex enough with organisms to ones without killing as in the case of predator.
The detritus food chain:
All the non-living organic matter in the ecosystem is collectively called detritus food chain begins with dead organic matter and passed to micro-organisms and then to detritivores and their predators. They chiefly depend on the inflow of organic matter produced by another system. In detritus food chain the energy flow remains as a continuous passage rather than as a stepwise flow between discrete entities. A prodigious quantity of organic matter is subscribed by the death of plants and animals and their execration products.
Detritus food chain is inter-connected with grazing food chain through some specific organisms having over lapping roles and which facilitates energy flow and material cycle between the two types of food chains. Overlapping organisms that form linkages and by which energy passes from detritus food chain back to grating food chain is especially crucial for ecosystem that depend on import of energy.