studying biotic structure of various ecosystems, scientists have noticed that all organisms are built into the food chain.And in each of these chains such ecosystems can be traced back much.According to him the substance that is the source of energy and building material moves from one organism to another.That is one organism eats another, and it in turn consumes a third.Here is a simple example of such a chain: grass - cow - people.
And all these circuits are rarely isolated from each other - they are all combined into one food web.Relationships in this network is quite complicated.For example, herbivores feed on several species of plants.And predators also not very choosy in selecting meat for their diet.However, despite the fact that many such food chains and they are quite diverse - they can fit into a single scheme.But this circuit looks like this: green plant - primary consumers - secondary consumers - tertiary consuments - propagator.And propagator always stand at the end of the food chain and of consumers there may be several.All these units are called trophic levels.
That is, from a scientific point of view trophic level - is the totality of organisms that occupy a certain place the food web.In normal ecosystem can count no more than 3-4 of these levels.The first trophic level - this is certainly the plant.With all of them begin the food chain.The second trophic level is occupied phytophages that is herbivorous.It consuments first order and eat only flora.
third trophic level is occupied by consumers of 2nd order.They are predators that eat only herbivores.Also, there may be euryphages that is omnivorous.They may equally eat both plant and animal food.These include swine, foxes, rats, cockroaches and the like.Man inherently is also euryphages.Also on this level and may be consuments third order - are predators that feed only carnivores.
The last trophic level usually busy decomposers, ie the heterotrophic organisms.They destroy, mineralizing and destructuring waste ecosystems.After their "work" obtained by simple mineral compounds.But decomposers in turn are divided into two classes.This detritus - animals that directly feed on organic residues and dead organisms.They are vultures, vultures, jackals, hyenas, earthworms and other "scavengers".
also decomposers are and destructors.They decompose dead already "organic" on inorganic compounds.Simply put, they support the processes of decomposition and decay.These include bacteria and fungi.And all these trophic chains are arranged so that producers, consumers and decomposers through them closely together.They maintain the integrity and structure of ecological communities, coordinating with the flows of matter and energy.This contributes to the regulation of the environment.
Graphically, this trophic structure of the ecological system can be represented as a pyramid of energy flows.Its grounds are producers or 1st trophic level.And all subsequent levels are the floors and the top of the pyramid.And in each of these levels there is a stream of energy.The energy that goes from one level is the energy input for the next.And the main reason for such a small amount in each trophic level ecosystem is that a considerable part of the energy during such transitions is lost.There is a rule of 10%, and according to him only as much useful energy is transferred to the next level.And 10% - is the maximum figure.In some ecosystems, such efficiency is equal to just one percent.
