Complete question:
A food web is a diagram that shows the interaction of organisms in an ecosystem. Which statement best describes the transfer of energy in a food web?
- The amount of energy transferred at each trophic level decreases because some is lost as heat.
- The amount of energy transferred at each trophic level is the same because energy is conserved in a system.
- The amount of energy transferred at each trophic level increases because the size of the organisms increases.
- The amount of energy transferred at each trophic level is different in land and marine ecosystems because the animals are different.
Answer:
The correct answer is
- The amount of energy transferred at each trophic level decreases because some is lost as heat.
Step-by-step explanation:
The trophic web is the process of energy transference through a series of organisms, in which every organism feeds on the preceding one and becomes food for the next one. The first link is an autotroph organism or producer, such as a vegetable, that can synthesize organic matter from inorganic matter. The next links are the consumers: herbivores are primary consumers and feed on producers. Carnivores are secondary consumers and feed on herbivores, and so on. The last links are the decomposers, microorganisms that act on dead animals degrading organic matter.
From the whole quantity of energy that reaches the earth's surface, only 0.1 or 1% is absorbed by autotroph organisms or producers.
From this input of solar energy, it begins a unidirectional energy flow through all the organisms in the ecosystem, from autotrophs to heterotrophs, until it is finally dissipated in the environment.
At each trophic level, it occurs an energy transfer from one level to the next, with only 10% being usable in each of them. This assessment is called "The 10% rule". This is, as a general rule, only about 10% of the energy stored as biomass at one trophic level, per unit time, ends up as biomass at the next trophic level, in the same unit of time.
The progressive reduction of energy determines the number of trophic levels (4 or 5). There are rarely more than four links, or five levels, in a trophic network. Over time, all the energy that flows through the trophic levels is lost as heat.