Ecological community is the collection of individuals belonging to different species, occupying the same habitat, at the same time. The interaction between these individuals for their survival gives rise to various food chains, which ultimately give rise to various food webs. This ScienceStruck article does an analysis of food chain vs. food web by describing the different aspects surrounding it.
Did You Know?
Keystone species are those whose presence has a significant impact on the survival of the ecological community.
Food chains and food webs serve as important tools in understanding how every individual of the ecological community, no matter how big or small, plays a role in the maintenance of the community as a whole. It helps us to understand how the reduction in the population of one individual causes a reduction in the population of other individuals. We also get to learn certain concepts like natural selection and behavioral adaptations of different plants and animals for their survival.
The food chain can be defined as a simple representation of who-eats-who. It is a chain of interdependence between different individuals of an ecology for their food. In other words, it is the feeding relationship between different individuals.
In nature, no food chain operates on its own. Every food chain is connected to other food chains by the individuals belonging to it. This interconnected network of food chains is called a food web. Each food chain is just one part of the food web.
How Does This Interconnection Arise?
A prey has an equal chance of being predated by more than one predator. Similarly, a predator has an equal chance of hunting down more than one type of prey. In a terrestrial ecosystem, a rat can be eaten by a snake, or by an eagle. Similarly, a snake can either eat a rat or a frog.
Every food chain or food web is made of different stages called trophic levels.
1st Trophic Level
The first trophic level comprises producers. Producers are plants. These utilize energy from the Sun and convert inorganic substances into organic food material, through the process of photosynthesis. In a way, they lock solar energy into a form that is more readily usable by other individuals. As these produce their own food, they are called producers.
2nd Trophic Level
All individuals that do not produce their own food, but depend on producers for their own food directly or indirectly are called consumers. The second trophic level comprises primary consumers. All herbivores (individuals that eat plants only) belong to this trophic level.
3rd Trophic Level
This trophic level comprises secondary consumers. Secondary consumers are individuals that feed on herbivores.
4th Trophic Level
This trophic level comprises individuals that feed on the secondary consumers and are called tertiary consumers. Sometimes, the tertiary consumer may be consumed by a higher-level consumer. Individuals who do not have any natural predators are called apex predators.
Only 10% of the total energy passes from one trophic level to the next trophic level, as most of the energy is consumed by the individual to do work. Due to this, a food chain is mostly made of 4 – 5 trophic levels only.
Comparison Between Food Chain and Food Web
Although a food chain is a part of the food web, there are a few basic differences between the two.
1. Single Pathway Vs. Network
2. Single Isolated Food Chains Vs. Complex Food Webs
In complex food webs, an individual of a particular trophic level, carnivore C, depends on many other herbivores for its food. So, the scarcity of herbivore B will not be detrimental to the survival of carnivore C and thus, it will also not affect the survival of carnivore D.
3. One Individual-One Trophic Vs. One Individual-Many Trophic Levels
4. Less Fit Vs. More Fit
By understanding how a food chain and, thereby, how a food web works, we are trying to understand the fine balance that exists in nature, which is essential for our very own survival.