Ecosystem –the flow of matterr and the flow of energy
that in the ecosystem every organism that is eaten or eats is a part of a food chain;
that producers, consumers and decomposers constitute the subsequent trophic levels.
to explain what the process of circulation of matter and flow of energy in an ecosystem consists of;
to explain why energy loss takes place while the matter is moving through the food system.
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Nagranie dźwiękowe dotyczące ekosystemu - obiegu materii i przepływu energii
Energy flows through the ecosystem
The energy of the sunlight is the base of the functioning of nature. The plants transform barely 1% of the energy of the sunlight that reaches their surface into chemical energy. This fraction of energy is stored in organic compounds and is enough for the producers to produce 150 bilion tonnes (150x10Indeks górny 1212 kg) of biomass.
The majority of the energy stored in the organic compounds is used by the plant to satisfy its basic needs of life, mainly breathing, but also the synthesis of the necessary organic compounds, or the transport of substance. None of the processes that happen in the cell is 100% effective, so a huge part of this energy is dispersed in the form of warmth. As an effect, only a fraction of the energy of the sunlight, which is absorbed by a plant during photosynthesis, is stored in chemical bonds of organic compounds of which the body of a plant is build.
Herbivores don’t eat entire plants, moreover, most of them are unable to digest cellulose. Because of that, they receive only a part of the energy stored in the plant. They use it to maintain their own life processes, which also causes loss of the energy, just like it’s in the case of plants. To the last trophic level, which is the level of decomposers, goes the energy present in the remains of dead organisms and in faeces, especially in the indigestible body parts such as feathers, bones and horns.
On every level of the food chain, the majority of the absorbed energy is dispersed and lost. It is estimated that every subsequent trophic level disposes of circa 90% less energy than the previous level. That means that the energy flows through the ecosystem, in which it’s used and dispersed.
The matter circulates in nature
Plants (and other producers) are a bond between the world of inanimate and living matter. It forms organic compounds, which build the bodies of plants, using simple inorganic substances. It moves through the food chain in the form of aliment, and finally reaches the decomposers. Here takes place another important phase of circulation of matter: microorganisms decompose the organic substances to simple mineral compounds, which can again be absorbed by producers. Matter is never actually lost or dispersed in the ecosystem – it only changes the form. Natural ecosystems are self‑sufficient. Thanks to the continuous circulation the matter is constantly transformed and used again. No redundant substances are formed, and substances don’t have to be provided from external sources.
Analyse the illustration „Detritus used as manure (horse feaces and hay)” and describe circulation of matter in this example. Write down the research question and the hypothesis. Next note down your observations and, at the end, the conclusions.
In artificial ecosytems, eg. farmlands, the circulation of matter is distorted. Humans collect and export almost the entire crop. In case of wheat, there are fruits (grain) as well as stems (straw). This ecosystem cannot function without supplying mineral fertilizer to the soil.
Gardeners produce the natural fertilizer, which accelarates the natural processes, on their own. They gather the remains of plants in the composter, providing conditions necessary for their decomposition. The fertilizer that is produced, can be used to fertilize the soil already in the next year.
Indicate the effects of mowing the grass regularly while not using any fertilizers on it.
Justify that the sentence ‘Nothing is lost in nature’ illustrates the process of circulation of matter in the ecosystem.
Indicate the main source of energy which is used by producers to produce all of the biomass in nature.
- geotermal energy
- sunlight energy
- oxidation of simple organic compounds
- the warmth of underwater volcanos
Put the phases of the circulation of matter in nature in the correct order.
- sythesis of organic compounds from the inorganic compounds conducted by the producers
- absorption of the organic compounds produced, on lower trophic levels, by the consumers
- decomposition of organic compounds to simple inorganic compounds
- death of organisms and the beginning of their decomposition
Conclusions
The source of energy in natural ecosystems is the sunlight.
Energy flows through all of the levels of the food chain and is gradually dispersed in the environment. Its losses are compensated by the continuous energy supply from the Sun.
In the ecosystems, the matter circulates between the living and inanimate of the ecosystem.
Keywords
energy flow, biomass, circulation of matter
Glossary
ekosystem – umownie wydzielony fragment przyrody składający się z elementów ożywionych i nieożywionych powiązanych ze sobą zależnościami, utrzymujący się w dynamicznej równowadze