Difference between Food Chain and Food Web
All living organisms are interdependent for their survival. Two major components of the ecosystem which allow the flow of nutrients and energy among different categories of organisms are the food web and the food chain. The geographical region in which all living organisms (feed, live, reproduce, interact and die) along with their non-living environmental components work together is termed as ecosystems.
A single straight pathway in which the transfer of energy occurs among different organisms is known as the food chain. Energy is neither created nor destroyed in this pathway but it keeps flowing via various organisms at different levels. Various organisms in an ecosystem like producers, consumers, and decomposers inter-connect via many food chains to form a food web.
Both pathways show that how energy and matter flow in different trophic levels. The trophic level consists of various stages of the food chain in sequences starting with producers from the bottom then comes primary, secondary and tertiary consumers. Each level in the food chain which dedicatedly performs its job is termed a trophic level. The feeding hierarchy of all trophic levels of an ecosystem has the following four major components:
· Sun (a major source of energy)
· Producers (include autotrophs, the first stage of the food chain)
· Consumers (include organisms which feed upon various other living organisms and is thought to be the largest part of the food web)
· Decomposers (include organisms which feed on detritus, last stage in the food chain)
Difference between food chain and food web occurs on basis of following points:
Food Chain
Food Web
Definition
The term food chain referred to a sequential pathway in which the flow of energy occurs from lower trophic levels towards higher trophic levels.
Numerous food chains combine together to form a food web that allows the flow of energy in the ecosystem.
Number of Chains
Single linear chain.
Many interconnected food chains.
Stability
Less stable, instability increases due to the increase in the number of confined and separate food chains.
More stable, stability increases due to complex food chains.
Disturbance’s cause
Disturbed easily by the removal of any group of organisms.
Does not disturbed by depletion of any group of organism.
Dependence
Higher trophic levels organisms rely upon a single kind of organism from the lower trophic level.
Higher trophic level’s organisms rely upon different kinds of lower trophic level’s organisms.
Trophic Levels
Few trophic levels (4–6) of different species.
Several trophic levels of different populations of species.
Types
Two types, detritus food chain and grazing food chain.
No type exists.
Adaptability
Organisms are less adaptable and less competitive.
Organisms are more adaptable and more competitive.
Food Chain
The flow of energy is a unidirectional process and the linear pathway in which energy transfer occurs from organisms of lower trophic level towards the organisms of higher trophic level is known as the food chain. Autotrophs (organisms that make their own food) are the primary organisms of the food chain. They usually comprise green plants but single-cell organisms are also present.
These are the organisms of the first trophic level in every food chain. Photosynthesis is the process by which these organisms can prepare their food by using sunlight as a glucose source, CO2, and water. Plants are most commonly known autotrophs but some unicellular organisms like algae and phytoplankton also have characteristics of autotrophs.
The food chain is less stable and usually got disturbed due to the elimination of a single group of organisms. Organisms in it are less adaptable and less competitive to changes that occur in their surroundings. Organisms from higher trophic levels have only a single type of species at the lower trophic level for their food needs.
Lower Trophic Level > Higher Trophic Level
Grass > Grasshopper (Primary Consumer) > Frog (Secondary Consumer) > Snake (Tertiary Consumer) > Hawk (Final Consumer)> Decomposer
The food chain is categorized into two types:
· Grazing food Chain
· Detritus food Chain
Grazing Food Chain
Autotrophs (green plants) are the major contributors to this food chain. It mainly consists of producers (green plants) > primary consumers (herbivores) > secondary consumers (carnivores). Primary consumers feed upon the producers, these primary consumers act as sources of food for various secondary consumers.
Detritus Food Chain
Detritus (dead organic matter) is the initiator of this food chain which was produced in the grazing food chain. Decomposers feed upon dead organic matter i.e. animal’s dead bodies and fallen leaves and ultimately predators decompose the organic matter. Carnivores (smaller ones) feed on detritivores which have consumed the energy after decomposing organic matter. The flow of energy is high in this category of the food chain. Various species of different organisms like bacteria, algae, protozoa, insects, fungi, etc. are present in this chain.
Food Web
The Foodweb is formed by the interconnection of various food chains. There exist similarities between the food web and food chain but the food web is much larger than the food chain. In the food web flow of energy occur precisely because more trophic levels are involved as compared to the food chain.
As it is a collection of different food chains if more cross relationships between food chains occur it will result in a more complex food web. The sustainability of the ecosystem is due to complex food webs. The interaction among different species in the food web is very clear. It plays an essential role in the study of community structure from top to bottom and vice versa.
It also shows energy flow from one community of organisms to another community e.g., from terrestrial to marine ecosystem or vice versa. It is more stable due presence of complex food chains and disturbance at any trophic level does not affect the efficiency of the whole food web. Organisms are more adaptable and competitive to changes that occur in their surroundings and feed upon various species of lower trophic levels.
Energy is a core requirement for the survival of all living entities. In an ecosystem, the unidirectional flow of solar energy continues within the communities and nutrients go through a constant process of cycling and recycling. The food chain is a process that allows the flow of energy and different nutrients in various living things while the food web is a natural linking of food chains. They both are necessary for balancing of energy level in the ecosystem.
References
· https://www.nationalgeographic.org/encyclopedia/food-chain/
· https://www.nature.com/scitable/knowledge/library/food-web-concept-and-applications-84077181/
