Presentation on the theme of the nitrogen cycle. Presentation "Circulation of Nitrogen in Nature" on biology - project, report
Slide 1.
Clade 2.
With rotting organic substances A significant part of the nitrogen contained in them turns into ammonia, which under the influence of the trifling bacteria living in the soil is then oxidized in nitric acid. The latter, entering into the reaction with carbonates in soil, for example, with calcium carbonate SASOZ, forms nitrates: 2HN0Z + SASOZ \u003d CA (NOZ) 2 + SOS + N0N
Slide 3.
A continuous loss of mineral nitrogen compounds would have long to lead to a complete cessation of life on Earth, if there were processes that compensate for the loss of nitrogen. Such processes include electrical discharges occurring in the atmosphere, at which there is always a certain amount of nitrogen oxides; The latter with water give nitric acid that turns into the soil into nitrates.
Slide 4.
Another source of replenishment of soil nitrogen compounds is the vital activity of so-called nitotobacteria, capable of absorbing atmospheric nitrogen. Some of these bacteria settle on the roots of plants from the legumes family, causing the formation of characteristic bloats - "Nuberkov", why they got the name of the nodule bacteria. Absorbing atmospheric nitrogen, nodule bacteria recycle it in nitrogen compoundsAnd plants, in turn, turn the latter in proteins and other complex substances.
Slide 5.
Thus, in nature, a continuous circular mouth of nitrogen is performed. However, annually with harvest with fields are cleaned by the most rich in protein parts of plants, such as grain. Therefore, fertilizers must be made in the soil, rewarding decrease in the most important elements of plant nutrition.
Type of lesson - combined
Methods:partially search, pro-bleed presentation, reproductive, explained-illustrative.
Purpose:
Awareness of students' significance of all discussed issues, the ability to build their relations with nature and society based on respect for life, to the whole living as a unique and invaluable part of the biosphere;
Tasks:
Educational: show the multiplicity of factors acting on organisms in nature, the relativity of the concept of "harmful and useful factors", the diversity of life on the planet Earth and options for adaptations of living beings to the entire spectrum of habitat conditions.
Developing: develop communication skills, the ability to independently produce knowledge and stimulate their cognitive activity; The ability to analyze information, allocate the main thing in the material being studied.
Educational:
Briefing the culture of behavior in nature, the quality of the tolerant personality, instilling interest and love for wildlife, form a sustainable positive attitude towards each living organism on Earth, to form the ability to see excellent.
Personal: Cognitive interest in ecology .. Understanding the non-accuracy of obtaining knowledge about the variety of biotic bonds in natural co-societies to preserve natural biocenoses. The ability to choose targeted and semantic installations in their actions and actions in relation to wildlife. The need for a fair assessment of their work and work of classmates
Cognitive: skill to work with various sources of information, pre-form it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.
Regulatory: The ability to organize independently performing tasks, evaluate the correct operation of the work, the reflection of its activities.
Communicative: participate in dialogue in the lesson; Answer the teacher's questions, comrades in the class, to perform in front of the audience using multimedia equipment or other means of demonstration
Planned results
Subject:know - the concept of "habitat", "Ecology", " environmental factors"Their influence on living organisms," links of living and non-living ";. Be able to determine the concept " biotic factors"; characterize biotic factors, bring examples.
Personal:express judgments, search and select information; analyze communication, compare, find the answer to the problematic question
MetaPermet: links with such academic disciplines As biology, chemistry, physics, geography. Plan actions with the goal; find the necessary information in the textbook and reference literature; analyze objects of nature; draw conclusions; Formulate your own opinion.
Form of organization learning activities - Individual, group
Teaching methods: illustrative, explanatory, illustrative, partially search, independent work With additional literature and textbook, with the COR.
Receptions:analysis, synthesis, conclusion, translation of information from one species to another, generalization.
Studying a new material
Crack of Nitrogen
Nitrogen cycle is an example of a self-regulating cycle with a large reserve fund in the atmosphere. Air, 78% co-standing of nitrogen, is the largest "reservoir" and at the same time due to its small chemical activity - the "safety valve" system. Nitrogen is constantly entering the atmosphere due to the activities of denintrifying bactenes and is constantly extracted from the atmosphere as a result of the activity of nitrogen-fixing bacteria and some algae (bio-chemical fixation of nitrogen), as well as the actions of electrical discharges during thunderstorms. The nitrogen cycle is consisted of the following processes: fixation, assimilation, nitrification, denitrification, decomposition, leaching, removal, falling out of precipitation, etc.
A nitrogen cycle in the biosphere is very peculiar and slowed. The fixation of nitrogen in the living substance is carried out - the limited number of living beings. Separate microorganisms contained in the soil and upper layers of the peace ocean are capable of splitting molecular nitrogen (N2) and use its atoms to construct the amino groups of proteins (-1CHN) and other organic compounds. Atmospheric nitrogen is absorbed by nitrogen-cultivate bacteria, some species of blue-green algae. They synthesize nitrates that become available to other bio-sphere plants. Nitrogen biofythixation is carried out by some baptics in symbiosis with higher plants in the soils (for example, nodule bacteria living on the roots of legumes rasters). After its death, the plants and animals return nitrogen into the soil, from where it comes to the new generations of rashes and animals.
A certain part of nitrogen in the form of molecules is returned to the atmosphere. In the soils, the process of nitrification occurs, which consists of a chain of reactions when the ammonium ion (in ^) is oxidized to nitrite (N02 ") or nitrite to nitrate (IOS-). Restoration of nitrite and nitrith-rates to a gaseous molecular nitrogen compound (N2) or nitrogen oxides (their) constitute the essence of the denitphi-kation process.
Prepared: Safronova Maria 9 "in" class
Nitrogen cycle - circulation by closed interconnected paths in the biosphere. Various microorganisms extract nitrogen from decomposing materials and translate it into the molecules necessary for them for metabolism. In this case, the remaining nitrogen is released in the form of ammonia (NH3) or ammonium ions (NH4 +). The other microorganisms are then associated with this nitrogen, translating it into the form of nitrates (NO3-). Entering plants, nitrogen is involved in the formation of biological molecules. After the death of the body, nitrogen returns to the soil, and the cycle begins again.
The main supplier of the associated nitrogen in nature is bacteria (from 90 to 140 million tons of nitrogen), for example, those that are in the magnets of leguminous plants.
Some nitrogen is translated into the associated state during a thunderstorm. The electrical discharge heats the atmosphere around itself, nitrogen is connected to oxygen (combustion reaction) with the formation of various nitrogen oxides (covers 10 million nitrogen per year).
In the course of human activity, nitrogen is also taking place and transfer it to the biosphere. Approximately 20 million tons of nitrogen per year binds when burning natural fuel.
Eutrophication (pollution of water bodies by algae) Lakes is the most unpleasant environmental problem associated with nitrogen. Nitrogen fertures lake algae, and they grow up, crowding out all other forms of life in this lake.
No nitrogen no protein, there is no life without protein. An animal body contains from 1 to 10%, in wool and horns - 15%, and animal protein substances are obtained from plants.
Nitrogen is one of the vital elements. Nitrogen is not fixed in the body in free form. Therefore, bacteria help in nature a nitrogen in nature.
general description
Nitrogen - the seventh element of the periodic table of Mendeleev. There are two valence - III and V. In nature, it is a dioxide gas (N 2), poorly soluble in water. Due to the durable triple bond between nitrogen atoms is a low-active substance that reacts only when heated or under the action of the catalyst.
Fig. 1. The structure of the nitrogen molecule.
The element is present in the soil, water, living organisms in the composition complex substances. Free nitrogen is relatively stable in the atmosphere, its content is 78% of the total volume of gases. Nitrogen can take liquid and solid forms.
The element is part of amino acids and proteins, nucleic acids. Without nitrogen it is impossible to build DNA.
Crooked
The circuit of the nitrogen cycle in nature can be divided into two parts - ground and atmospheric. A nitrogen cycle through the soil is carried out as follows:
- as a result of rotting organic substances (plants, animals), nitrogen turns into ammonia (NH 3);
- under the action of Bacteria ammonia is oxidized to nitric acid (HNO 3);
- nitric acid reacts with soil elements, forming acidic salts (nitrates) - CASSO 3, Ca (NO 3) 2;
- nitrates absorb plants.
The atmosphere of nitrogen also falls as a result of rotting or when burning organic substances, such as wood or peat. Under the action of lightning discharges, nitrogen is connected to oxygen, forming nitrogen oxide (II) - NO, and then nitrogen oxide (IV) - NO 2.
Oxides react with water, forming nitric acid. It falls into the soil along with rains, where nitrates are formed.
In addition, free nitrogen is capable of absorbing nitrogen-fixing bacteria and some types of blue-green algae. Nitrogen intimidating bacteria (nitrogen) are in symbiosis with plants. For example, the nodule bacteria live on the roots of leguminous plants. Azotfixators can absorb nitrogen in the presence or in the absence of oxygen, i.e. May be aerobs or anaerobes. They also synthesize nitrates.
Fig. 2. Nitrogen-fixing bacteria on the tubers.
Plants can absorb nitrogen only in the composition of nitric acid salts. Together with the leaves of nitrogen falls first in the body of herbivores (Considers of the first order), and then - predatory animals (second-order consversions). Nitrogen returns during rotting and as part of urea (CH 4 N 2 O).
Fig. 3. Scheme of nitrogen cycle in nature.
Some nitrates are oxidized by special denitrifying bacteria to free nitrogen, which is returned to the atmosphere. The process of restoring free nitrogen from complex compounds is called denitrification.
What did we know?
The description of the nitrogen cycle in nature. Nitrogen is an important element needed by living organisms for the construction of tissues and DNA synthesis. Free nitrogen is poorly in reaction due to durable triple ties. Therefore, bacteria, synthesizing ammonia, nitric acid, nitrates help in the absorption of nitrogen. The azot salts fall into plants and further on the food chain in the organisms of herbivores and predatory animals. The new cycle begins when moving and decomposition of living organisms.
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