In this paper, we invite you to consider what the biological cycle is. What are its functions and significance for the living organisms of our planet. We will also pay attention to the issue of the energy source for its implementation.
What else you need to know before considering the biological cycle is that our planet consists of three shells:
- lithosphere (hard shell, roughly speaking, this is the earth we walk on);
- hydrosphere (where all water can be attributed, that is, seas, rivers, oceans, and so on);
- atmosphere (gaseous shell, the air we breathe).
There are clear boundaries between all layers, but they are able to penetrate each other without any difficulty.
Cycle of matter
All these layers make up the biosphere. What is the biological cycle? This is when substances move throughout the biosphere, namely in the soil, air, in living organisms. This endless circulation is called the biological cycle. It is also important to know that everything begins and ends in plants.
Under the cycle of substances lies an incredibly complex process. Any substances from the soil andatmospheres get into plants, then into other living organisms. Then, in the bodies that absorbed them, they begin to actively produce other complex compounds, after which the latter get out. We can say that this is a process in which the interconnection of everything on our planet is expressed. Organisms interact with each other, the only way we exist to this day.
The atmosphere has not always been as we know it. Previously, our air envelope 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 were able to bring the state of our atmosphere into the form that humans need. Air and plants are absorbed by herbivores, they are also included in the menu of predators. When animals die, their remains are processed by microorganisms. This is how the humus necessary for plant growth is obtained. As you can see, the circle is complete.
Power source
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:
- air;
- soil;
- vegetation.
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 is sucked up by the roots of various trees. If the water managed to penetrate very deep, then it replenishes groundwater reserves, and some of it even returns to rivers, lakes, seas and oceans.
As you know, when we breathe we take in oxygen and exhale carbon dioxide. So, trees need solar energy in order to process carbon dioxide and return oxygen to the atmosphere. This process is called photosynthesis.
Cycles of the biological cycle
Let's start this section with the concept of "biological process". It is a recurring phenomenon. We can observe biological rhythms, which consist of biological processes constantly repeating themselves 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 the 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 diems;
- seasonal;
- annual;
- perennial;
- centuries old.
The most pronounced annual cycles. We observe them always and everywhere, you just need to think a little about this issue.
Water
Now we offer you to consider the biological cycle in nature using the example of water, the most common compound on our planet. She has many capabilities, which allows her to participate in many processes asinside the body as well as outside it. The life of all living things depends on the cycle H2O in nature. Without water, we would not exist, and the planet would be like a lifeless desert. She is able to participate in all vital processes. That is, we can draw the following conclusion: all living beings on planet Earth simply need clean water.
But water is always polluted as a result of any processes. How, then, to provide yourself with an inexhaustible supply of clean drinking water? Nature took care of this, we should thank for this existence of that very water cycle in nature. We have already discussed how this all happens. Water evaporates, collects in clouds and falls as precipitation (rain or snow). This process is called the "hydrological cycle". It is based on four processes:
- evaporation;
- condensation;
- rainfall;
- water runoff.
There are two types of water cycle: large and small.
Carbon
Now we will look at how the biological cycle of carbon occurs in nature. It is also important to know that it occupies only 16th place in terms of the percentage of substances. It can be found in the form of diamonds and graphite. And its percentage in coal exceeds ninety percent. Carbon is even present in 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 neededto 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, it is found in large quantities in the 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:
- soil;
- water resources.
It is also found in the human body, namely, it is part of:
- proteins;
- nucleic acid;
- bone tissue;
- lecithins;
- fitins and so on.
It is phosphorus that is necessary for the accumulation of energy in the body. When an organism 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 nutrient cycle.
Nitrogen
Now we will look at the nitrogen cycle. Before that, we note that it makes up 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 called nitrogen fixation. When a plant dies and rots, the nitrogen it contains enters 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 in the soil. In addition, it should be mentioned that nitrogen is also released in its pure form as a result of plant decay 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. Sulfide sulfur can be processed by microorganisms, so sulfates are born. The latter are absorbed by plants, sulfur is part of the essential oils. As for the body, we can meet sulfur in:
- amino acids;
- proteins.
