Teaching Documents by Tapan Dutta
Energy can have many forms-kinetic, potential, light, sound, gravitational, elastic, electromagne... more Energy can have many forms-kinetic, potential, light, sound, gravitational, elastic, electromagnetic or nuclear. According to the law of conservation of energy, any form of energy can be converted into another form and the total energy will remain the same. For eg: a laborer when pushes the pile of bags, his potential energy stored inside him is converted into the kinetic energy from the movement of matter or when you burn the wood it's chemical energy is converted into the heat energy or when you charge your mobile phone the electrical energy is converted into the chemical energy which gets stored inside the battery's molecules. The many different natural and renewable energy technologies highlighted throughout the website are by no means breakthrough. Many of the renewable energy technologies have been around for years, and as time goes by, are increasing in efficiency. What are the sources of energy? Energy are broadly classifies into two main groups: renewable and Non-renewable. Renewable Energy Renewable energy is energy which is generated from natural sources i.e. sun, wind, rain, tides and can be generated again and again as and when required. They are available in plenty and by far most the cleanest sources of energy available on this planet. For eg: Energy that we receive from the sun can be used to generate electricity. Similarly, energy from wind, geothermal, biomass from plants, tides can be used this form of energy to another form. Non-Renewable Energy A non-renewable resource is a natural resource which cannot be produced, grown, generated, or used on a scale which can sustain its consumption rate. These resources often exist in a fixed amount, or are consumed much faster than nature can create them. Fossil fuels (such as coal, petroleum and natural gas) and nuclear power (uranium) are examples. In contrast, resources such as timber (when harvested sustainably) or metals (which can be recycled) are considered renewable resources. Why should we conserve energy? Energy needs to be conserved to protect our environment from drastic changes, to save the depleting resources for our future generations. The rate at which the energy is being produced and consumed can damage our world in many ways. In other words, it helps us to save the environment. We can reduce those impacts by consuming less energy. The cost of energy is rising every year. It is important for us to realize how energy is useful to us and how can we avoid it getting wasted. To start saving energy is not a big thing at all. We can start saving the energy from our home itself, just by turning off the lights during day hours, washing clothes in cold water or using public transport instead of using our own vehicle and later can implement these things on much wider scale at society level, then at city level then district level and finally at country level. You might notice a small change in your monthly bills
Evolution Diversity of Life
The Tiger, Panthera tigris
Mechanism of Hormone Action
1 TOXIC CHEMICALS IN THE ENVIRONMENT There are a number of chemicals in the environment. Some of ... more 1 TOXIC CHEMICALS IN THE ENVIRONMENT There are a number of chemicals in the environment. Some of these are toxic and the rest non-toxic. The toxic chemicals are discharged by industries into air, water and soil. They get into the human food chain from the environment. Once they enter our biological system they disturb the biochemical processes, leading in some cases to fatal results. Chemical toxicology is the science of the study of toxic chemicals and their modes of action. The list of toxic chemicals is very long. It is intriguing that even now there are many cases where one is not sure whether a particular chemical compound is toxic or not. Some useful and important chemicals are being controlled rigorously as their non-toxicity has not been proved. There are valid confusions in respect of elements; where will the line be drawn between the 'essential limit' and 'toxic limit'? Such subdivision (toxic essential) is artificial and can be misleading. Many metals listed as environmental hazards are essential dietary trace elements required for normal growth and development of animals and human beings.
Culture or cultivation of bacteria under artificial conditions
viz. optimum temperature or under... more Culture or cultivation of bacteria under artificial conditions
viz. optimum temperature or under optimum gaseous atmosphere & by providing appropriate metabolic substrates in the form of ‘media’.
Taxonomy and Diversity Purpose of taxonomy is to provide useful ways for identifying and compar... more Taxonomy and Diversity Purpose of taxonomy is to provide useful ways for identifying and comparing organisms. Another goal is to assess the extent of diversity of different types of organisms. There are two very different ways to construct a taxonomy: 1. Phenetic system: groups organisms based on mutual similarity of phenotypic characteristics. May or may not correctly match evolutionary grouping. Example: group (motile) organisms in one group, non-motile organisms in another group. This is useful, but does it reflect underlying evolutionary ancestry? o Numerical Taxonomy: a common approach to phenetic taxonomy o Use a variety of characteristics: e.g., Gram stain, cell shape, motility, size, aerobic/anaerobic capacity, nutritional capabilities, cell wall chemistry, immunological characteristics, etc. o Relies on similarity coefficients o If use 10 characteristics, then match organisms. o Ex. A and B share 8 characters out of 10: similarity coefficient Sab is 8/10 = 0.8 o Can use many such values to establish similarity matrix o Dendrograms help display this information clearly. Note: dendrogram is just a graphical display of similarity coefficients; but one often assumes that these are representative of a deeper evolutionary relationship. This may or may not be legitimate conclusion, depending on the traits used. 2. Phylogenetic system: groups organisms based on shared evolutionary heritage. Example: Mycoplasma (no wall) and Bacillus (walled Gram+ rods) are not obviously similar, would not be grouped together phenetically. But evolutionarily they are similar, more so than either to Gram-organisms. o The diagram below is a hypothetical evolutionary diagram, superficially similar to a dendrogram but actually quite different, since it seeks to portray an accurate picture of how and when organisms diverged from common ancestors over time.
SDS-PAGE Procedure Prepare the separating gel
Air-pollution and its control
Fertilization Q. What are the cortical reaction? What are the role play by ZP3 and IP3 in activat... more Fertilization Q. What are the cortical reaction? What are the role play by ZP3 and IP3 in activation of ovum during the fertilization? Describe in brief the acrosomal reaction of spermatozoa during fertilization? Role of Ca 2+ in the fertilization. What are the fast block to polyspermy and slow block to polyspermy? β-catenin and its role in fertilization. What are the molecular changes in capacitation? Major Events of Fertilization 1. Recognition events between sperm and egg: species specificity 2. Regulation of sperm entry into egg: block to polyspermy. 3. Fusion of sperm and egg genetic material 4. Activation of developmental process within the egg The main function of fertilization is to combine the haploid sets of chromosomes from two individuals into a single diploid cell, the zygote. In addition, fertilization activates the egg. Egg activation blocks entry by additional sperm, stimulates the final meiotic division, and triggers the onset of embryonic development. The sea urchin is one of the several model organisms that has been used to decipher the basic cellular and molecular biology of animal fertilization. More is known about fertilization in sea urchins than is known about fertilization in most vertebrates. In animals in general, fertilization is the direct interaction and fusion of two germinal cells (one "egg" and one spermatozoan), resulting in the initiation of cleavage, gastrulation and the species-specific developmental program that characterizes each organism. In sea urchins, a discrete series of steps characterizes fertilization (Vacquier, 1998). Each of these steps is discussed below in detail and many may be visualized in the electron microscopical study of Anderson (1968), in the video essay provided by Mark Terasaki (1998) or the web site of Epel, 1991).
Eutrophication What is eutrophication? How many types of eutrophication? How it is differ from ea... more Eutrophication What is eutrophication? How many types of eutrophication? How it is differ from each other? What are the factors responsible for eutrophication? What are the environmental impacts of eutrophication? What are the event taken place during the process of eutrophication? Add a short notes on eutrophication of lake & river or eutrophication of marine system. Are eutrophication both beneficial and detrimental? – Justify. How can Eutrophication be Avoided? The term eutrophication was introduced by German hydrologist C.A. Weber (1907) to describe nutrient rich condition. Eutrophication is the process by which lakes. Rivers and Coastal waters become increasingly rich in plant biomass as a result of the enhanced input of essential plant nutrients. This contrasts with oligotrophic water which is unproductive because restricted available of nutrients and mesotrophic water which is intermediate between these two states (Wetzel, 1975). The term eutrophication has also been used to describe the slow, natural process by which a geologically young and unproductive water body gradually increases in productivity as nutrients accumulated over time and as the water basin become shallow due to sedimentation (Wetzel, 1975). According to Urban waste water treatment Directive (1991) eutrophication may be defined as the enrichment of water by nutrients especially compounds of nitrogen and phosphorus causing an accelerated growth of algae and higher farms of plant life to produce an undesirable disturbance to the balance of organism and the quality of water concerned. Types of eutrophication :-Eutrophication are of two types — The gradual accumulation for nutrients and organic biomass accompanied by increased level of production and a decrease in the average depth of the water column caused by sediment accumulation constitute the natural eutrophication process. Cultural eutrophication is simply the anthropogenic acceleration of eutrophication. Cultural eutrophication may be beneficial to many aquatic systems Controlled fertilization of ponds or similar enclosed aquatic systems is a basic technique used in aquaculture to produce large crops of finishes and shellfishes. Cultural eutrophication may create problems if the system of interest is not properly managed.
Any locus with allele frequencies in equilibrium is not evolving, because there is no genetic cha... more Any locus with allele frequencies in equilibrium is not evolving, because there is no genetic change over time. Changes in gene frequencies indicate evolution in progress, but changes may take place at some gene loci and not at other in any population at any time. We will now see how the Hardy Weinberg theorem can be used to obtain quantitative information on evolutionary processes and how different factors influence the nature and pace of genetic modification in evolving population. Mutation and Gene frequencies One of the causes responsible for a change in gene frequency is the frequency of mutation itself. Recurrent forward mutation, A a, reduce the frequency of A and increase that of a in the gene pool and the reverse mutation a A have the opposite effect. The rate of forward mutation, u and the rate of reverse mutation v, are expressed as proportions of alleles mutating per generation. The actual value of total alleles of a gene changing from A to a in one generation is p0; from a to A, it is vq0 (when allelic frequency for A = p0 and for a = q0). The extent of the mutation effect depends on the initial frequencies of the alleles as well as the mutation rates, which is implicit in the terms up and vq. The net change in the frequency of A or p is – p = vq – up. The new frequency of allele A or p1 is the sum of initial frequency plus the change in frequency of A or P1= P0+p (when both forward and backward mutation occur). For example, if P0 = 0.8 and q0=0.2 and the mutation rate =10-5 and v = 10 –8 ; then net change in gene frequency for p (i.e.p) is p = (10 – 8 x 0.2) (10 5 x 0.8) = (2 x 10 9) (8 x 10 6) = 7.998 x 10 6 = ~ 8 x 10 6 (rounded off from 7.998 x 10 6). The new frequency of allele A (p1) is now P1 = 0.8 + (8 x 10 6) = 0.799992 and, q1 = 0.200008 The net effect of mutation in one generation in this case is only eight more a alleles (and eight fewer A) per million gametes making up the gene pool for the new generation. The allele frequency ultimately reach an equilibrium when no further changes occurs as the result of mutation alone. This is expressed as p = up vq = 0 or u p ˆ = v q ˆ (where p ˆ and q ˆ are the equilibrium frequencies of A and a respectively).
Oil Pollution of Water Bodies
Definition: Chromatography is a laboratory technique that is used to separates and to identify co... more Definition: Chromatography is a laboratory technique that is used to separates and to identify components within a mixture by using the differential affinities of the components for a mobile medium and for a stationary adsorbing medium through which they pass. Principle: Chromatography is based on differential migration. The solutes in a mobile phase go through a stationary phase. Solutes with a greater affinity for the mobile phase will spend more time in this phase than the solutes that prefer the stationary phase. As the solutes move through the stationary phase they separate. This is mainly based on the following properties: • Capillary Action – the movement of liquid within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension. The liquid is able to move up the filter paper because its attraction to itself is stronger than the force of gravity. • Solubility – the degree to which a material (solute) dissolves into a solvent. Solutes dissolve into solvents that have similar properties. (Like dissolves like) This allows different solutes to be separated by different combinations of solvents. Separation of components depends on both their solubility in the mobile phase and their differential affinity to the mobile phase and the stationary phase.
At one time, the success of a fishing trip often depended on a fisherman's keen sense of sight, s... more At one time, the success of a fishing trip often depended on a fisherman's keen sense of sight, smell and hearing. To that end the value of a high vantage point, the crow's nest, to scan for fish was appreciated. Modern aircraft and satellites have raised mankind's vantage point to a level undreamed of by earlier generations; at the sametime, devices have been developed which have expanded man's perceptions far beyond the limits of the human senses. The combination of these technologies has resulted in the modern science known as remote sensing which may be defined as the acquisition of information about an object or event without being in physical contact. We are just starting to discover some of the ways in which remote sensing can be applied to man's centuries-old quest to harvest food from the sea. This manual is intended to be an introduction to the field of remote sensing for persons involved in the study, management or utilization of fisheries resources, particularly in developing countries. Although some forms of remote sensing have been in existence for many years and are generally well understood, extraordinary advances have taken place during the past two or three decades, both in the technology and in its application. The sheer volume of literature now available in this field and of technical knowledge needed to understand it makes an introductory manual of this kind essential. It is beyond the scope of this text to attempt a complete or comprehensive description of modern remote sensing or even to document all of the ongoing research programs and their application to the locating and capture of fish. Rather it is intended to provide the reader with a basic understanding of some of the terms, concepts and specific systems used in remote sensing and, through case studies, to illustrate some applications of importance to fisheries personnel. Basic Terms and Concepts Remote sensing may be defined as the acquisition of information about an object or event on the basis of measurements taken at some distance from it. In practice the term is normally used to describe the collection and analysis of data made by instruments carried in or above the earth's atmosphere. A sensor is a device which detects and measures a physical parameter, such as radiation, and converts it into a form which can be stored or transmitted. In other words, it is the device which " sees " the objects or terrain towards which it is pointed. While devices which sense gravity, magnetic fields or sound waves can properly be classified as remote sensors, many authors restrict their use of the term remote sensing to describe measurements of electromagnetic radiation. That convention will be followed in this manual although a brief section is included on underwater acoustic devices such as sonars and echo sounders because of their importance to the fishing industry. Electromagnetic radiation (EMR) is a type of energy which appears in such forms as X-rays, visible light, microwaves and radio waves. While these forms of EMR may initially seem to be separate phenomena, they are in fact part of a continuous spectrum. This can be understood best by considering how a prism separates white light into different colours; each colour represents a different wavelength of light. Visible light is the only segment of EMR which human vision can detect. A given sensor can detect EMR only over a limited range of wavelengths: this range is referred to as a spectral band. The width of the spectral band, i.e. the extent of the limited range of wavelengths detected, is referred to as spectral resolution. Some sensors are comprised of a number of detectors, each of which is sensitive to a different spectral band. These are called multispectral or multiband sensors. By our looking at the earth in two or more bands simultaneously, it is possible to discriminate a wider range of features. The combination of typical responses coming from a specific target seen by a sensor in various spectral bands is called the spectral signature of that target.
Growth is very complex biological process involving cell division, enlargement of new cells and t... more Growth is very complex biological process involving cell division, enlargement of new cells and their differentiation in different types of tissues. Though the fate of growth is different in plants and animals but the principle of growth are quite same in the both cases. Definition: Apart from the cell division and enlargement of new cells, growth is also associated with an increase in the dry weight of the growing parts, so it can be defined as the change in the size (length and weight) over time or energetically change in calories and stored in so matic abd reoroductive tissue. The energetic definition of the growth is particularly useful for understanding the factors that affect growth in fishes become injected food energy, measured in calories must emerge either as energy expanded for metabolism or growth or as energy execrated. The metabolic energy expenditure can include calories expanded for: 1) Body maintenance and repair. 2) For digesting food, respiration and least beat (BMR). 3) Movement. The excreated energy can take the form of : 1) Facces 2) Ammonia 3) Area and a small quantities of mucaus and slought epidermal scalls of fish. The remaining factors in the energetic equation of growth is I = M + G + E Where, I = injected food energy, M = expanded for metabolism; G = growth ; E = excreation. Phases of Growth: Growth occurs in three phases: 1) The phase of cell formation in which the new cells are formed and number of cells is increased in the organism. 2) The phase of cell maturation in which individual cells become matured and expand and more efficient at that time. 3) The phases of cell enlongalion in which maximum elongatia and specialization of cells occurs. Course of Growth: Growth is not a gradual process rather it is dynamic and varies in course of life even under constant environmental conditions. If the change in dry weight is plotted against time, and 'S'-shaped or sigmoid curve, called the grand-period curve, is obtained. It is seen from the curve that growth is slow at the initial stage (Lag phase); at the next phase (Log phase) the growth rate increase until it reaches a phase of steady state. The total period of this course of growth is called the grand period of Growth. After the steady state the organisms or its parts undergoes Senescence and death. Factors which affect on the Growth in fish:-Growth is positive, i.e. increase the weight over time, so energy balance in metabolism is indicated. Metabolism is the sum of catabolism and anabolism, thus rate of anabolism is the principle factors controlling process of growth are growth hormones secreted
(The transport of deeper water to shallow levels and vice versa) Since the wind varies from place... more (The transport of deeper water to shallow levels and vice versa) Since the wind varies from place to place, so does the Ekman transport, forming convergence and divergence zones of surface water. A region of convergence forces surface water downward in a process called downwelling, while a region of divergence draws water from below into the surface Ekman layer in a process known as upwelling. Upwelling and downwelling also occur where the wind blows parallel to a coastline. The principal upwelling regions of the world are along the eastern boundary of the subtropical ocean waters, as, for example, the coastal region of Peru and northwestern Africa and west coast of India. Upwelling in these regions cools the surface water and brings nutrient-rich subsurface water into the sunlit layer of the ocean, resulting in a biologically productive region. Upwelling and high productivity also are found along divergence zones at the equator and around Antarctica. Nutrient-rich water rises from deeper levels to replace the surface water that has drifted away and these nutrients are responsible for supporting the large fish population commonly found in these areas. The effectiveness of upwelling and its ability to support abundant sea life is greatly dependent upon the depth of the thermocline. While the primary downwelling regions are in the subtropical ocean waters—e.g., the Sargasso Sea in the North Atlantic. Such areas are devoid of nutrients and are poor in marine life. Fig1 Due to Ekman transport, coast-parallel winds drives the surface layer of water almost directly offshore. Removing the surface layer causes deeper water, usually colder and more nutrient-rich, to upwell along the coast. Because of the frictional stresses that exist between ocean layers, surface water is transported at a 90 degree angle to the left of the winds in the southern hemisphere, 90 degrees to the right of the winds in the northern hemisphere. The vertical movements of ocean waters into or out of the base of the Ekman layer amount to less than one metre per day, but they are important since they extend the wind-driven effects into deeper waters. Within an upwelling region, the water column below the Ekman layer is drawn upward. This process, with conservation of angular momentum on the rotating Earth, induces the water column to drift toward the poles. This is why winds blowing northward parallel to the coastline "drag" surface water westward away from shore. Conversely, downwelling forces water into the water column below the Ekman layer, inducing drift toward the equator. An additional consequence of upwelling and downwelling for stratified waters is to create a baroclinic field of mass (see above). Surface water is less dense than deeper water. Ekman convergences have the effect of accumulating less dense surface water. This water floats above the surrounding water, forming a hill in sea level and driving an anticyclonic geostrophic current that extends well below the Ekman layer. Divergences do the opposite; they remove the less dense surface water, replacing it with denser, deeper water. This induces a depression in sea level with a cyclonic geostrophic current.
In the course of development of the different farming systems of fishes, it has been found that f... more In the course of development of the different farming systems of fishes, it has been found that fish culture can also be integrated with crop and livestock farming which is known as integrated fish farming. These mutually reinforcing aquatic and terrestrial production systems totally recycle the entire farm produce. This farming system holds great promise ad potential for augmenting the production of animal protein, betterment of rural economy and generation of employment. Although the technology of composite fish culture is a high yielding one, its high input requirements, especially on artificial feed and fertilizers acts as major constraint in the adoption of the technology by rural people. The cost on inputs can be reduced considerably by recycling available enormous organic cuaster, both from plant and animal origin. Fish-Cum-Livestock farming: Livestock waster such as cattle dung, pig dung, chicken and duck droppings provide all the raw materials required for the food chain in a fishpond. On decomposition they enrich the soil and water with nutrients thereby sustaining the fertility of the pond. Livestock wastes decompose at a slower rate and thus nutrients are released gradually. In livestock-cum-fish farming, the feed given to the animals is used three times over. Once by the livestock, then by the fish by directly feeding on the animal excreta and lastly through production of natural fish food by recycling of dung. The pig dung contains 70% digestible food for fish. Fish-Cum-Pig farming: A 0.1 ha pond was stocked at the stocking density of 8500 fingerlings /ha in the species ratio of Catla 2.0; Rohu 2.0; Mrigal 2.0; Silver carp 1.5; Grass carp 2.0; and common carp 0.5. The pond was maured by pig dung collected from adjacent pig-sites. No supplementary feed or fertilizer was applied. Grass carp was fed on chopped green cattle fodders such as maize leaves and hybrid napier grass. Lime was applied four times during the course of experiment @200 kg/ha each time. Simultaneously intensive rearing of two lots of piglets was done during the experimental period. The first lot of 8 piglets attained average weight of 95.4 kg from their initial average weight of 22.5 kg in 8 months. The second lot of 5 piglets grew to 65.5 kg from their initial average weight of 25.0 kg in 4 month. To overcome any mineral deficiency sodium was provided once a week. After twelve months, the pond yielded 730 kg of fish which corresponds to a production rate of 7300 kg/ha/year and through rearing of two lots of piglets in 12 months a total of 1095.7kg of pig flesh was produced. About 2000kg pig flesh was dung recycled in 0.1 ha pond during the experiment. In India, fish-cum-pig farming has a special significance in improving the socioeconomic status of section of weaker rural community. Fish-Cum-Duck Farming: The experiment was conducted in a 1.48 ha pond by the Operational Research Project at Krishnanagar, West Bengal. The average depth of the pond was 1.5m. The ducks moved in the pond during day time but during night they were housed in a floating duck house made of bamboo mating over empty oil drums in the pond. The pond was initially stocked with fingerlings of Indian and Chinese carps at a stocking density of 6340 fingerlings/ha, in the species ratio C 1.0; R 1.8; M 2.8; SC 1.5; GC 1.0 and CC 1.9. After 9 months partial harvesting was done and a second stock of Catla fingerlings was added to the existing stock and the species ratio accordingly changed to C1.2; R 1.3; M 2.7; Sc1.2; GC and CC 2.5. During day time the experiments of the ducks were automatically recycled as the ducks moved over the whole pond surface. Night droppings collected from the duck houses were added to the pond. No supplementary feed pond fertilizer was used in the pond. Lime was applied twice during the course of the experiment @ 250 kg/ha. 100 ducklings (a cross between khaki Campbell and Bengal runner) were reared in the pond. The ducks initially depended upon natural food presorts in the pond, but later on balanced poultry feed was given. The feed was supplemented with chopped aquatic areas and molluscs. Aster 12 months, the pond yielded a total of 6,397.3 kg of fish, which corresponds to a production rate of 4,323 kg/ha/year. The ducks laid 1,835 eggs and a total of 2,500 kg of duck flesh was produced in one year. The states of Tamil Nadu, Kerala, Asam, Orissa, West Bengal and Bihar abound in duck population which are mainly used for egg production. These states have great potential for fish culture where duck-cum fish farming can be fruitfully adopted. Fish-cum-poultry farming : The work on integration of fish culture with poultry farming has been initiated in India recently and full results are not available to present. However, it has been reported that poultry manure is a self contained organic manure having characteristics of both organic as well as inorganic manure.
Q. What are the properties of water of lotic water bodies? What are the main zones of any lotic s... more Q. What are the properties of water of lotic water bodies? What are the main zones of any lotic system? Describe in brief about adaptive modification of organisms of lotic system 2+3+7=12 Moving water or lotic systems includes rivers, streams and related environment and which is differ from the lentic habitat in following respects :
Inland water bodies their Physicochemical characters
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Teaching Documents by Tapan Dutta
viz. optimum temperature or under optimum gaseous atmosphere & by providing appropriate metabolic substrates in the form of ‘media’.
viz. optimum temperature or under optimum gaseous atmosphere & by providing appropriate metabolic substrates in the form of ‘media’.
latitabilis was found to be dominant. The water body under investigation was considered moderately polluted. On the basis of Diversity index, Evenness value and Dominance value indicated the equitability and heterogeneity of the aquatic system. While Coleoptera and Odonata exhibited a peak in July and May respectively but no distinct peak could be seen for Hemiptera. Correlation between the abiotic factors and insect species revealed that abiotic factors had some regulatory effects on aquatic insect population.