The biological cycle. The role of living organisms in the biological cycle

In this paper, we suggest that you consider what a biological cycle is. What are its functions and significance for living organisms of our planet. We will also pay attention to the issue of the source of energy for its implementation.

What else you need to know before we consider the biological cycle is that our planet consists of three shells:

• Lithosphere (hard shell, roughly speaking, this is the land on which we walk);
• Hydrosphere (where you can include all the water, that is, the sea, rivers, oceans, etc.);
• Atmosphere (gaseous envelope, the air we breathe).

Between all layers there are clear boundaries, but they can penetrate each other without any difficulty.

Cycle of substances

All these layers constitute the biosphere. What is the biological cycle? This is when substances move through the entire biosphere, namely in soil, air, in living organisms. This is an infinite circulation and is called the biological cycle. It is important to know that everything starts and ends in plants.

Under the cycle of substances there is an incredibly complex process. Any substances from the soil and the atmosphere get into the plants, then into other living organisms. Then in the bodies that have absorbed them, they begin to actively develop other complex compounds, after which the latter are selected outward. We can say that this is a process in which the relationship of everything on our planet is expressed. Organisms interact with each other, only so we exist to this day.

The atmosphere was not always the way we know it. Earlier, our air shell was very different from the current one, namely it was saturated with carbon dioxide and ammonia. How, then, did people appear who use oxygen for breathing? We should thank the green plants that managed to bring the state of our atmosphere to the right kind for the person. Air and plants are absorbed by herbivores, they also enter the menu of predators. When animals die, their remains are processed by microorganisms. This is how humus is obtained, which is necessary for plant growth. As you can see, the circle is closed.

Power source

A biological cycle is impossible without energy. What or who is the source of energy for organizing this exchange? Of course, our source of thermal energy is the star of the Sun. The biological cycle is simply impossible without our source of heat and light. The sun heats up:

• air;
• Soil;
• vegetation.

During heating, evaporation of water occurs, which begins to accumulate in the atmosphere in the form of clouds. All the water will eventually return to the surface of the Earth in the form of rain or snow. After her return she impregnates the soil, and the roots of various trees suck in her. If the water has penetrated very deeply, it replenishes the reserves of groundwater, and some part and does return to rivers, lakes, seas and oceans.

As you know, when breathing, we absorb oxygen, and exhale carbon dioxide. So, solar energy is needed by trees and in order to process carbon dioxide and return to the atmosphere oxygen. This process is called photosynthesis.

Cycles of biological circulation

We begin this section with the concept of "biological process". It is a repetitive phenomenon. We can observe biological rhythms, which consist of biological processes that are constantly repeated at certain intervals.

Biological process can be seen everywhere, it is inherent in all organisms living on planet Earth. It is also part of all levels of the organization. That is, inside the cell, and in the biosphere, we can observe these processes. We can distinguish several types (cycles) of biological processes:

• Intra-daily;
• Daily allowances;
• Seasonal;
• Year;
• Perennial;
• Centuries-old.

The most pronounced are the annual cycles. We observe them always and everywhere, it is only necessary to think a little about this question.

Water

Now we suggest that you consider the biological cycle in nature using the example of water, the most common compound of our planet. It has many capabilities that allows it to participate in many processes both inside the body and outside it. The life of all living things depends on the cycle of H ₂ O in nature. Without water, we would not be, and the planet would be like a lifeless desert. It is able to participate in all vital processes. That is, we can draw the following conclusion: all living beings of the planet Earth simply need clean water.

But the water is always polluted as a result of any processes. How then can we ensure an inexhaustible supply of clean drinking water? Nature has been concerned about this, we should thank for this existence the very cycle of water in nature. We have already considered how this all happens. The water evaporates, collects into clouds and precipitates (rain or snow). This process is commonly called the "hydrological cycle". It is based on four processes:

• evaporation;
• condensation;
• precipitation;
• Water flow.

There are two types of water cycle: large and small.

Carbon

Now we will look at the biological cycle of carbon in nature. It is also important to know that it is only 16th in terms of the percentage content of substances. Can occur in the form of diamonds and graphite. And the percentage of it in the coal is more than ninety percent. Carbon even forms part of the atmosphere, but its content is very small, about 0.05 percent.

In the biosphere, thanks to carbon, just a mass of various organic compounds is created that are necessary for all life on our planet. Consider the process of photosynthesis: plants absorb carbon dioxide from the atmosphere and process it, as a result we have a variety of organic compounds.

Phosphorus

The importance of the biological cycle is large enough. Even if we take phosphorus, it is contained in large quantities in bones, it is necessary for plants. The main source is apatite. It can be found in igneous rock. Living organisms can extract it from:

• Soil;
• Water resources.

It is contained in the human body, namely it is part of:

• Proteins;
• Nucleic acid;
• Bone tissue;
• Lecithins;
• Fishes and so on.

It is phosphorus that is necessary for the accumulation of energy in the body. When the body dies, it returns to the soil or to the sea. This promotes the formation of rocks rich in phosphorus. This is of great importance in the biogenic cycle.

Nitrogen

Now we will look at the nitrogen cycle. Before that, we note that it is about 80% of the total volume of the atmosphere. Agree, this figure is quite impressive. In addition to being the basis of the composition of the atmosphere, nitrogen is found in plant and animal organisms. We can meet it in the form of proteins.

As for the nitrogen cycle, we can say this: nitrates are formed from atmospheric nitrogen, which are synthesized by plants. The process of creating nitrates is commonly called fixation of nitrogen. When the plant dies and rot, the nitrogen contained in it gets to the soil in the form of ammonia. The latter is processed (oxidized) by organisms living in soils, so nitric acid appears. It is able to react with carbonates, which are saturated with soil. In addition, it should be mentioned that nitrogen is released in pure form as a result of rotting plants or in the process of combustion.

Sulfur

Like many other elements, the sulfur cycle is very closely related to living organisms. Sulfur enters the atmosphere as a result of volcanic eruptions. Sulphide sulfur can be processed by microorganisms, so sulphates appear on the light. The latter are absorbed by plants, sulfur is a part of essential oils. As for the organism, we can meet sulfur in:

• Amino acids;
• Proteins.