In this paper, we suggest you consider what the biological cycle is. What are its functions and significance for living organisms of our planet. We will also pay attention to the issue of energy source for its implementation.
What else you need to know before we consider the biological cycle is that our planet consists of three shells:
- lithosphere (a hard shell, roughly speaking, is the earth we walk on);
- hydrosphere (where all water can be attributed, that is, seas, rivers, oceans, and so on);
- atmosphere (gaseous shell, air that we breathe).
There are clear boundaries between all layers, but they can penetrate each other without any difficulty.
Substance cycle
All these layers make up the biosphere. What is a biological cycle? This is when substances move throughout the biosphere, namely in soil, air, in living organisms. This endless circulation is called the biological cycle. It is important to know that everything begins and ends in plants.
An incredibly complex process is hidden under the cycle of substances . Any substances from the soil and the atmosphere enter the plants, then into other living organisms. Then, in the bodies that absorbed them, they begin to actively develop other complex compounds, after which the latter get out. We can say that this is a process in which the interconnectedness of everything on our planet is expressed. Organisms interact with each other, the only way we exist to this day.
The atmosphere was not always as we know it. Previously, our air shell was very different from the current one, namely it was saturated with carbon dioxide and ammonia. How then did people who use oxygen to breathe appear? We should thank the green plants, which were able to bring the state of our atmosphere into the form necessary for a person. Air and plants are absorbed by herbivores, they also enter the menu of predators. When animals die, their remnants process microorganisms. This is how humus is obtained, which is necessary for plant growth. As you can see, the circle is closed.
Source of energy
The biological cycle is impossible without energy. What or who is the source of energy for organizing this interchange? Of course, our source of thermal energy is the star Sun. The biological cycle is simply impossible without our source of heat and light. The sun heats up:
During heating, water evaporates, which begins to accumulate in the atmosphere in the form of clouds. All water will eventually return to the Earth's surface in the form of rain or snow. After her return, she soaks the soil, and the roots of various trees suck her in. If the water managed to penetrate very deeply, then it replenishes the reserves of groundwater, and some part even returns to rivers, lakes, seas and oceans.
As you know, when we breathe, we absorb oxygen, and exhale carbon dioxide. So, trees also need solar energy in order to process carbon dioxide and return oxygen to the atmosphere. This process is called photosynthesis.
Biological Cycle Cycles
We begin this section with the concept of "biological process." It is a recurring phenomenon. We can observe biological rhythms, which consist of biological processes that are constantly repeating at certain intervals.
The biological process can be seen everywhere, it is inherent in all organisms living on planet Earth. It is also part of all levels of organization. That is, both inside the cell and in the biosphere, we can observe these processes. We can distinguish several types (cycles) of biological processes:
- intraday
- per diem;
- Seasonal
- annual;
- perennial;
- centuries-old.
The most pronounced annual cycles. We observe them always and everywhere, it is only worth a little thought on this issue.
Water
Now we suggest that you consider the biological cycle in nature by the example of water, the most widespread compound of our planet. She has many capabilities, which allows her to participate in many processes both inside the body and beyond. The life of all living things depends on the H 2 O cycle in nature. Without water we would not have been, and the planet would have been like a lifeless desert. She is able to participate in all vital processes. That is, we can draw the following conclusion: all living creatures of the planet Earth simply need clean water.
But water is always contaminated as a result of any processes. How then to provide yourself with an inexhaustible supply of clean drinking water? Nature worried about this, we should thank for this existence of the very water cycle in nature. We already examined how this all happens. Water evaporates, collects in clouds and precipitates (rain or snow). This process is called the "hydrological cycle." It is based on four processes:
- evaporation;
- condensation;
- precipitation;
- water runoff.
Two types of water cycle can be distinguished: large and small.
Carbon
Now we will consider how the biological carbon cycle occurs in nature. It is important to know that it takes only 16th place in terms of percentage of substances. It can be found in the form of diamonds and graphite. And its percentage in hard coal exceeds ninety percent. Carbon is even 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 are created that are needed by all living things 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 value of the biological cycle is quite large. Even if we take phosphorus, then 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 are able to get it from:
It is contained in the human body, namely it is part of:
- proteins;
- nucleic acid;
- bone tissue;
- lecithins;
- phytins 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 contributes to the formation of rocks rich in phosphorus. This is of great importance in the biogenic cycle.
Nitrogen
Now we will consider the nitrogen cycle. Before this, we note that it makes up about 80% of the total atmosphere. Agree, this figure is quite impressive. Besides the fact that it is the basis of the composition of the atmosphere, nitrogen is found in plant and animal organisms. We can meet him in the form of proteins.
As for the nitrogen cycle, we can say this: nitrates are synthesized from atmospheric nitrogen, which are synthesized by plants. The process of creating nitrates is called nitrogen fixation. When a plant dies and rots, the nitrogen contained in it enters the soil in the form of ammonia. The latter is processed (oxidized) by organisms living in the soil, so nitric acid appears. It is able to react with carbonates, which are saturated with soil. In addition, it is necessary to mention the fact that nitrogen is released in its pure form as a result of rotting plants or during combustion.
Sulfur
Like many other elements, the sulfur cycle is very closely associated with living organisms. Sulfur enters the atmosphere as a result of volcanic eruptions. Microorganisms can process sulfide sulfur, so sulfates appear in the light. The latter are absorbed by plants, sulfur is part of the essential oils. As for the body, we can find sulfur in: