The power-supply circuit represents the sequence of living organisms which transfer energy, eating each other. There are two types of food chains: some begin with remains of organisms and come to an end with microbes and bacteria, and others originate from plants. Explanation for this fact simple: plants only of all living beings who receive energy from inorganic substances.
Power-supply circuit
The nature is arranged in such a way that some organisms are a power source, to be exact – food, for others. Herbivorous eat plants, predators hunt herbivorous or other predators, deathbirds eat remains of living beings. All these relations become isolated in chains, on the first place which producers are, and consumers – konsument of different orders follow then. The majority of chains is limited to 3-5 links. Example of a food chain: a grass – a hare – a tiger.
Actually many power-supply circuits are arranged much more difficult, they branch, become isolated, form complex networks which is called trophic.
The majority of power-supply circuits begin with plants – they are called pasturable. But there are also other chains: they originate from the decayed remains of animals and plants, excrement and other waste, and the microorganisms, small animals and other beings eating such food follow further.
Plants at the beginning of a power-supply circuit
On a power-supply circuit all organisms transfer energy which consists in food. There are two types of food: autotrophic and heterotrophic. The first consists in receiving nutrients from inorganic raw materials, and heterotrophs use organic chemistry for life.
The clear boundary between two types of food does not exist: some organisms can receive energy in both ways.
It is logical to assume that at the beginning of a food chain there have to be autotrophs which will transform inorganic substances to organic chemistry and can be food for other organisms. Heterotrophs cannot begin power-supply circuits as they need to receive energy from organic compounds – that is, one link has to precede them at least. The most widespread autotrophs are plants, but there are also other organisms which eat the same way, for example, some bacteria or phytoplankton. Therefore not all power-supply circuits begin with plants, but nevertheless vegetable organisms are the cornerstone of most of them: on the land it is any representatives of the higher plants, in the seas – seaweed. In a power-supply circuit before autotrophic plants there cannot be other links: they receive energy from the soil, waters, air, light. But there are also plants heterotrophs, they have no chlorophyll, they live at the expense of other plants or hunt animals (generally on insects). Such organisms can combine two types of food and stand both at the beginning, and in the middle of a power-supply circuit.