Current Affairs 9th Class

        Introduction   Health is one of the important aspects of human life. Health and diseases are interconnected with each other. Our body is made up of cells and tissues. Cells are made up of variety of chemical substance, such as, proteins, carbohydrate, fats and so on. There are various specialized activities in our bodies and all the activities are interconnected with each other. Whenever there is malfunctioning of any organ of the body, it affects the entire system of the body and our body start functioning abnormally. This situation is called the diseases. Thus, diseases can be defined as the abnormal functioning of the body.              Significance of Health Health is considered as the complete physical, mental, and social fitness of an individual. If we remain healthy we can lead happy life. There are many factors which affects our health. The diseases may be air born, water born or food born. Some of the diseases are infectious and are caused by microorganisms such as bacteria, protozoa, fungi, virus, etc. Thus, to prevent diseases we need to keep our environment and our surroundings clean and hygienic. The personal and community hygiene is equally important to keep ourself healthy. Since we live in a society, individual health is important to keep our society healthy. We must take care of the garbages, which should not be left open on the street and in the open areas. We should have closed drainage system so that germs are not allowed to breed in the contaminated water of the drain. The drainage system should have no blockage in it to keep the dirty water flowing and there should not be stagnation of water. Thus, the condition essential for good health are: better sanitation, clean drinking water, adequate nutritious food and social harmony. To keep ourself healthy we must take balance diet. The balanced diet promotes healthy growth of our mind and body. It keeps us mentally sharp and alert to fight any sort of problems.                 Causes of Diseases The abnormal functioning of the body is called the diseases. There, may be several reasons for causing diseases. The various factors causing the diseases have been divided into two factors as intrinsic factors and extrinsic factors. Here in this part we will discuss both of them separately and in details:              Intrinsic Factors The diseases causing factors that lies inside the human bodies is called intrinsic factors. The diseases like kidney failure, heart diseases, genetic disorder, hormonal imbalance, allergy etc are caused due to intrinsic factors. Such diseases are also called metabolic diseases. The diseases like kidney failure can occur due to acute or chronic problems. Acute problems may arise due to the injuries to the abdomen parts of the more...

       Biogeochemical cycles   There is continuous transfer of energy between the various components of the biosphere. Both living and non living components of the biosphere constantly interact with each other for this purpose. The living organisms derive its nutrients from the earth for their growth and development, known as biogeochemical. These biogeochemical are constantly recycled and used again and again. The different biogeochemical cycles are: water cycle. Nitrogen cycle. Carbon cycle, and oxygen cycle. We will discuss about all these cycles in details below:                Water Cycle Water is considered to be one of the most important liquid for the survival of life process on the earth surface. The water constantly circulates between land, air, sea and living organisms and this is known as water cycle.       The heat of the Sun evaporates water from the water bodies. These water vapours go up in the atmosphere, cool down and gets collected as a cloud. These clouds, on condensations, turn into the small droplets of water. On getting heavier they fall back on the earth in the form of rain, snow or hails.            Nitrogen Cycle Nitrogen is present in maximum quantity in the air. It is nearly 78% in the air. It is also present in all life forms in the form of proteins, amino acids and nucleic acids. In atmosphere it is in molecular form. The plant uses the atmospheric nitrogen in the form of nitrate and is converted in this form by nitrogen fixation.       The leguminous plant like pea plant contains nitrogen fixing bacteria such as azotobactor and rhizobium in its root nodules. These bacteria converts atmospheric nitrogen into nitrates. When animals consume the plants, it breaks down the nitrogenous compound. When the animals or the plants die, some bacteria carry out ammonification and produce ammonium ions \[NH_{4}^{^{+}}\]. This process of formation of ammonia is called ammonification. Some of the microorganisms convert this ammonia into nitrates, again reduced back to nitrogen and released back into the atmosphere. This process is known as denitrification.               Oxygen Cycle Oxygen is one of the important constituent of our atmosphere and is also the main components of water. It is nearly 21% in our atmosphere. The living organism uses the atmospheric oxygen for the process of respiration and releases carbon dioxide into the atmosphere. This carbon dioxide is used by the plant for the process of photosynthesis to pressure their own food and there after releases oxygen back into the atmosphere.                             more...

        Air Pollutions   Contamination of air by poisonous gases released by various means and many other chemicals is called air pollution. The main reason for air pollution is the rapid industrialization and urbanization. This rapid growth and development is reducing the area under the forest leading to the release of gases like sulphur dioxide, carbon dioxide, carbon monoxide, nitrogen oxide, hydrogen sulphide, lead oxide in the atmosphere. Many poisonous gases released by industries and factories, in the atmosphere. In today’s time the main reason for the air pollution is also the large number of vehicles on the roads. These air pollutants can cause respiratory problems, renal problems, high blood pressure, nervous problems and many other health hazards.                 The large scale release of gases like sulphur dioxide in the atmosphere cause acid rain which makes the soil very acidic and hence affects the plants and animals. It also leads to the reduction in production of food grains due to loss, that is, of fertility of the soil. The air pollution cause two major ecological problems, green house effect and ozone layer depletion. The green house effect is due to the increase in the concentration of carbon dioxide, which leads to the heating up of the atmosphere and hence cause global warming. The other is the ozone layer, which is a thick blanket of \[{{O}_{3}}\] molecules called the isotopes of oxygen that protects us from the harmful ultraviolet radiation. These harmful ultraviolet radiation can cause skin cancer, immune deficiency, cataracts and damages the plants and forest.                                   The main region for the hole in the ozone layer is the release of CFC gases. The CFC gas consists of chlorine, fluorine, and carbon. Thus, if we have to protect our atmosphere we have to stop the use of harmful gases like CFC that              Water Water is considered to be a wonderful liquid and all the life forms on the earth is possible due to the water only. About 75% of the earth surface is covered with water, but the concentration of fresh water i.e. potable water is very less and is nearly 2.5%. This entire water bodies is called hydrosphere. The fresh water are found in river, ponds, lakes, glacier of mountains, and underground. Water is essential for the survival of life forms on the earth.                                     Water is considered to be essential because all the reaction that takes place within our body and within the cells occurs in the liquid more...

         Introduction   The resources which are provided to us by the nature are called natural resources. Earth is the only planet where life exists. This is because of the fact that the conditions on the earth surface is favorable for the existence of life. The natural resources of the earth are land, water and air. Water covers 75% of the earth's surface and air forms the blanket over the surface of the earth called atmosphere. All the components atmosphere, lithosphere and hydrosphere together constitute biosphere. There are two components of ecosystem, biotic and abiotic components. The biotic components include living organisms like plants and animals where as abiotic components include air, water and land. The status of complexity and interdependence among the various components of the environment is due to the perfect and systematic cycling of various chemical that is water, oxygen, carbon and nitrogen. Our physical environment is formed by various nonliving things around us. They play very important role in the growth and development of the living components. For example, the plants prepare their food by the process of photosynthesis using sunlight, water and carbon dioxide and animals derive its food from plants in the process. There is change in temperature, pressure, humidity, rainfall etc of a particular place and these components constitutes the weather condition of a place. The average weather condition of an area constitute the climate. The most important factors of climate is temperature and seasonal variations of a region.           Role of Atmosphere in Climate Control Air is one of the important natural resources and no life will be possible without air. The atmosphere forms a blanket over the surface of earth and maintains the variation of temperature and pressure on the earth during days and nights. It helps to keep the temperature of earth at optimum for the survival of life. It do not allow the drastic variation of temperature during days and nights. If there would have been no atmosphere, then there would have been a drastic change in temperature during days and nights, as in the case of moon where temperature varies from - 190°C to 110°C.               Movement of Air (Winds) The movement of wind is due to the difference of pressure in the lower layer and upper layer of the atmosphere, on land and water bodies. Some time strong breeze and some time gentle breeze blow in the atmosphere. All these phenomenon is the result of change that takes place in the atmosphere due to pressure difference on land and water bodies.                          When solar radiation falls on the earth, some are absorbed. But most of them are reflected back into the atmosphere by the land more...

      Animal Husbandry   It is the branch of science which deals with the rearing and management of animals, for commercial purposes. Some of the common animals used for rearing are cow, goat, buffalo, fish, poultry, and bee keeping.

• Cattle Farming: Cattle farming is done for two purpose, that is, for milk and transportation. Cows are classified as drought breed, dairy breed, and dual purpose breed. Milk producing cows are called dairy breed. There are two high yielding breeds of cows such as indigenous breed and diary breed. Indigenous breed of cows include red shindhi, sahiwal, gir.

Some of the high yielding breeds of buffaloes are Murrah, Mehsana and Surti. The lactation period for these animals are different. For example, for red shindhi it is 321 to 345 days, for sahiwal it is 184 to 354 days, and for Gir it is 230 to 394 days. There are two methods of breeding animals, such as, natural method and artificial methods. In artificial methods semens of desired male bull is injected into the genital tract of female animal, during the deat period and fertilization takes places. It is known as artificial insemination. Now the cattle feed is also equally important. The animal feed includes two types of substance: Roughage and Concentrates. The roughage largely consists of fibres, silage, hay and legumes, while the concentrates includes the mixtures of substance which are rich in vitamins, minerals, and carbohydrates. The common diseases which are found in catties and buffalo are parasitic disease such as ticks and mites, and infectious disease includes foot and mouth disease, anthrax, hemorrhagic septicemia, black quarter etc.

• Poultry Farming: Rearing and management of hen for meat and eggs is called poultry farming. There are three types of poultry indigenous, exotic and cross breeds. The Indigenous breeds includes aseel, kadaknath, bursa. The indigenous breeds are hardy and possess natural immunity against some of the common diseases. They are smaller in size and grows very slowly and lay less number of eggs. The other one is exotic breeds which include white leghorn, rhode island red. They are larger in size and lay large number of eggs. They take less time to grow and produce more meat. The third is the cross breeds which includes HH260, IBL80, B77, and IIS82.

Some of the common traits of new variates of poultry are: it should be able to produce large number and large quantity of meats in less time and should be able to adjust in various climatic conditions. It should have law maintenance cost and product should be high nutrients. Some of the common diseases founded in the poultry are caused by virus, such as, bird flu, cholera, aspergillosis etc.

• Fish Production: The rearing and management of fish on large scale for commercial purposes is called pisciculture. There are two types of fisheries: marine water fisheries and fresh water fisheries. The marine fisheries includes fisheries of more...

        Crop Production Management   India is a large country with three fourth of the population depending on agriculture. Natural resources like forest, agriculture, and fisheries are the main stay for Indian economy. Due to the subtropical climate and lack of forest in most part of country, crop can be grown throughout the year. In India there are three types of farmer that is small farmers, marginal farmers, and progressive farmers. The extent to which farmer can grow crops depends on his financial condition and the resources he can have.

• Nutrient Management: Just as human being needs nutrient for his growth and development, the plants also requires nutrient for its proper growth and development. Plants get its nutrients from soil, water and air. There are sixteen nutrients required by the plants for its proper growth and development. These nutrients are divided into two groups as macronutrients and micronutrients. Out of these, carbon and oxygen are supplied by air, hydrogen is supplied by water and remaining thirteen nutrients are supplied by soil.
• Micronutrients: The nutrients which are required by the plants in small quantity are called the micronutrients. There are seven micronutrients such as chlorine, zinc, copper, iron, manganese, boron, and molybdenum.
• Macronutrients: The nutrients which are required by the plants in large quantity are called macronutrients. There are six macronutrients as nitrogen, phosphorous, potassium, calcium, sulphur and magnesium.

                                  Manure Manures are obtained from the natural materials, such as, decomposition of plant waste and animal waste. These manures include compost, green manures, vermicompost, and farmyard manure. These manures helps to improve the physical properties of soil, reduce the soil erosion, increase the moisture holding capacity of soil and are cheaper. It also do not cause environmental pollution. There are some disadvantages of using natural manure the nutrient content of manure is very low and hence required in large quantity. They are inconvenient to store and transport from one place to another. Further it is not nutrient specific and hence not useful when a particular nutrient is required by the plant or the soil is deficient in particular nutrient. Different types of manures are:   Compost: It is prepared by decomposition of plant waste, animal wastes and urins of animals. They are collected in a pit and allowed to decompose overa long period of time, by the microorganisms, in the presence of oxygen. It takes about three to four month to prepare the compost.        Green Manure: The green manure is prepared by growing the crop for six to eight week and then mulching it into the field by ploughing and mixing it with the soil. These crops are left buried into the field for about one to more...

       Introduction   We know that all the living orga  nisms need food for their survival. We use both plants and animals for our food, but most of our food is obtained from agriculture and animal husbandry. The population of our country is above one billion and still increasing at very fast rate. Hence the demand of food is also increasing day by day, but the land area under cultivation is not increasing and is almost fixed. We do not have enough space for expansion, but at the same time we have to meet the requirement of the food. Therefore, we have to increase the food production using advanced technique for agriculture. While our effort have increased the food production but at the same time it is using the natural resources extensively and is getting depleted very fast. As a result, we are causing more and more da mage to our environment and disturbing the natural balance. Therefore, the need of the hour is to follow sustainable use of resources. Simply increasing the food production cannot solve the problem of malnutrition and hunger. The food security depends on both availability of food and access to it. The scientific management practices should be undertaken to obtain high yields from agriculture and animal husbandry. The different methods we should follow to increase the food production are mixed farming, intercropping and integrated farming practices.            Improvement in Crop Production The successful management of natural resources for agriculture to satisfy the human needs, at the same time maintaining the quality of environment and conserving natural resources, is called sustainable agriculture. Agriculture can also be defined as the science dealing with the mass production of plants and animals, useful for human needs. Different crops require different climatic condition, temperature and photoperiod for the growth and development. In India there are two major crop season Rabi and kharif crop season.  

• Rabi Season Crops: The crops which grows during the month of October to March are called rabi crops. For example wheat, rice, grams, pea, mustard, etc.
• Kharif season crops: The crops which grow during summer season i.e. during the month of June to October are called kharif crops. For example paddy, soyabean, arhar, maize, barley etc.

  The crop yields can be increased by following methods as:

• Variety Improvement
• Production improvement
• Crop Protection Management

             Crop Variety Improvement We can improve the crop production by incorporating certain quality like high yields and disease resistant. Such traits can arise through mutation. We can improve the variety of seeds with an incorporation of the desirable character by hybridization, mutation, polyploid, and DNA recombinant technology. A gene of hybrid is inserted into the DNA of lowbrid plants and the plant express DNA of hybrid plant. It is called transgenic plants. Hybridization: The cross over more...

         Tissues   A group of cell performing similar function is called tissue. Both plants and animals contains tissues which are different in nature. In this part we will discuss about both plant and animal tissue.                Plant Tissue Plant tissue is divided into two types Meristematic tissue and Permanent tissue. First we will discuss about meristematic tissue.                Meristematic Tissue The meristematic tissues are the continuously dividing tissues, which are found in the growing region of the plant. It helps in growth and development of the plant. According to their position in the plant, it is of three types, such as, apical meristem, intercalary meristem, and lateral meristem. The apical meristem is found in the root tips or the shoot tips of the plant. It helps in longitudinal growth of the plant.   The lateral meristem is found in the bark and in vascular bundles of the dicot roots and stems of the plant, whereas the intercalary meristem is found at the base of the leaves or i.nternodes. The main function of the meristematic tissue is to form new cells and helps in the growth of the plant. The apical meristem helps in longitudinal growth, lateral meristem helps in diametrically growth and intercalary meristem increases the length of the organ of the plant.                Permanent Tissue These tissues develop from meristematic tissue. Actually these are the meristematic tissue which have lost the power of division. It is further subdivided into two groups as simple permanent tissue and complex permanent tissue. The simple permanent tissues are composed of similar cells. It is of three types: Parenchyma, Collenchyma, and Sclerenchyma.   Parenchyma Tissue: These cells are living and still possess the power of division. They are founded in different shapes such as round, oval, elongated etc. It has thin cell wall and small nucleus. It is founded in stem, roots, leaves and fruits of the plant. It helps in filling the space between the other tissues and provides turgidity and rigidity to the plants. It also stores and assimilates food for the plants.     Collenchyma: It is similar to that of parenchyma, except for deposition of extra cellulose at the corner of the cells. The intracellular space are generally absent and contain few chloroplast. They are located below epidermis and didribs of dicot leaves. The main function of the collenchymas tissue is to provide mechanical strength and elasticity to the plants. It also provides flexibility to the stems, which helps in bending of stems.    

• Sclerenchyma: These are basically dead cells and its walls are made up of thick deposition of more...

       Cell   All the cell possess the following three basic characteristics. First all the cell contain genes in the form of DNA and RNA which have coded information for the regulation of cellular function. Secondly, they contain plasma membrane made up of protein and lipids. This allows the exchange of material between the cells. Thirdly, they have a metabolic machinery called cytoplasm which contain various cell organelles. An organism may be of single celled or multicellular. The unicellular organism includes bacteria, amoeba, Euglena, paramecium and yeast. All the cell is capable of carrying out certain basic function such as nutrition, respiration, growth and reproduction. Thus, all the living organisms are divided into two forms, Prokaryotic and Eukaryotic cells.               Prokaryotic Cells The cell in which nuclear region is not surrounded by a nuclear membrane and nucleus and cytoplasm cannot be differentiated is called prokaryotic cell. These organisms have primitive and incomplete cells. It consists of a single chromosome which is in direct contact with cytoplasm. However, ribosomes are present in such cell. For example, cyanobacteria, archaebacteria.                    Eukaryotic cells In this cell nuclear region is bounded by nuclear membrane. The nucleus and cytoplasm can easily be differentiated. They also contain membrane bound organelles and more than one chromosomes are presents in the nucleus. Cell division occurs by miotic or meiotic cell division. It may be unicellular or multicellular organisms.                 Structure of Cell All the cell basically consists of three parts such as plasma membrane, nucleus and cytoplasm. All the metabolic activities within the cell is possible due to these features in the cell.                Plasma Membrane It is a thin layer of membrane which covers the outer most layer of the cell. It is present in microorganism, plant and animals. It is selectively permeable and can be seen only under the high power microscope. It is formed by phospholipids, proteins, cholesterol and polysaccharides. It has got fluid mosaic model.   According to this model plasma membrane is made up of a bilayer of phospholipids and two types of protein, that is intrinsic and extrinsic proteins. The protein presents in the membrane provides enzymes for catalyzing chemical reactions, transport protein for movement of water soluble ions, pumps for active transport and receptor proteins for endocytosis. Presence of lipids provides flexibility to the membrane. The function of plasma membrane is that it regulates the entry and exit of selected material in the cell, hence it is also called the selectively permeable. The movement of material takes place by diffusion and osmosis. Some substances like carbon dioxide, oxygen, water, etc. move by the more...