Question

Taking into consideration both the size and number of organisms at each trophic level, explain the relationship between biomass and trophic levels. What are the advantages of measuring trophic levels by the number of individuals? What are the advantages of measuring trophic levels by the amount of biomass? While studying a terrestrial ecosystem, be clear, thorough, and scientifically accurate.

Answer 1

Ans. As we go through various trophic levels of a food chain, we find that the lowest trophic level is comprised of autotrophs. As we rise higher above to higher trophic levels, the complexity of organisms increases from herbivores to carnivores to omnivores. The energy flow in a food chain,occurs from the autotrophs, to primary consumers, to secondary consumers. So, as the energy flows, more of it is wasted and less amount of it is transferred from one trophic level to another. As less amount of energy is available with increasing hierarchy of trophic levels, so the number of organisms decreases with progress across the food chain. Therefore, biomass decreases with increasing trophic levels of food chain.

Each and every trophic level is associated with utilisation of ceratin amount of resources and energy. As we count the number of individuals in a particular trophic level, we can have an estimate of how much resources are consumed by a certain trophic level. We can also get an idea of biomass produced and energy utilised by that trophic level.

Biomass represents the amount of material obtained from plants or animals, that can be used for energy production. We know that energy can neither be created nor destroyed, it can only be converted from one form to another. Also the amount of net energy flow decreases from lower to higher trophic levels. So, when we take into account biomass with respect to each trophic level of a food chain, we can find out that how much energy is used by the living organism, and how much is wasted as heat or other forms.