Tag: food chain and food web

A fish consuming phytoplanktons occupies primary consumer level while when consuming another small fish, it occupies secondary consumer level. So, a fish can occupy more than one trophic level in a pond ecosystem.

A trophic level is a group of organisms within an ecosystem which occupy the same level in a food chain. There are five main trophic levels within a food chain, each of which differs in its nutritional relationship with the primary energy source. The primary energy source in any ecosystem is the Sun. Primary producers are usually plants and algae, which perform photosynthesis in order to manufacture their own food source. Primary producers make up the first trophic level. The second trophic level consists of herbivores, these organisms gain energy by eating primary producers and are called primary consumers. Trophic levels three, four and five consists of carnivores and omnivores. Trophic level three consists of carnivores and omnivores (Example: Man) which eat herbivores; these are the secondary consumers. 

A man feeding on curd occupied the third trophic level. Here, the grasses are at the first trophic level, the cow/buffalo who feeds on grasses is at the second trophic level. The curd is prepared by the milk of cow/buffalo by the action of bacteria, but the energy of the milk is getting transferred to the man, so man is at the third trophic level.

Food web represents an interconnection of many food chains in an ecosystem and that is the reason in a food web, there can be organisms occupying different trophic level at the same time. For example, in a food web, a crow can be at the second trophic level or at the fourth trophic level.

The trophic level is the sequential arrangement of several organisms on the basis of the number, energy flow, and biomass present at the different level. Food chains start at trophic level 1 with primary producers, such as plants, move to herbivores at level 2, predators at level 3 and finish with carnivores or apex predators at level 4 or 5. Thus, the correct answer is option D.

Vultures are scavenging birds that feed on dead animals. Vultures do not kill their own prey, they feed on dead animals. As scavengers, vultures play an important role in the ecosystem by decomposing the dead animal matter, cleaning the environment and reducing the spread of diseases.