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About Reproduction

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Reproduction is one of the characteristics of an organism. Organisms give rise to other organisms of the same kind in life time and then continues its generation. The process of reproduction may be of various types. Diversified reproductive processes are being observed. I shall try to discuss all reproduction of Human and flower reproduction here.

What is Reproduction? 

Reproduction is a biology process by which new organisms are generated. So it means that Reproduction is the process of producing babies or young animals and plants. It is the mechanism of species continuation.
The known methods of reproduction are broadly grouped into two main types:

1. Asexual Reproduction Process
2. Sexual Reproduction Process

1. Asexual Reproduction Process

In this system, an individual can reproduce without involvement with another individual of that species. The division of a bacterial cell into two daughter cells is an example of asexual reproduction. Asexual reproduction is not, however, limited to single-celled organisms. Asexual reproduction needs only one parent, unlike sexual reproduction, which needs two parents.


Since there is only one parent, there is no fusion of gametes and no mixing of genetic information. As a result, the offspring are genetically identical to the parent and to each other. They are clones. Asexual reproduction happens in lower animals. Asexual reproduction occurs in different ways.
Such as – budding, binary fission, fragmentation etc.

2. Sexual Reproduction Process

 

The process through which two animals of opposite sex (male and female) compete for their reproduction by means of producing male and female gametes, fertilizes and produce offspring is called reproduction. The process of sexual reproduction involves two parents. Both parents normally contribute one gamete or sex cell to the process. This process assures that the genetic information given to the offspring will be obtained equally from each parent. The female gamete is called the egg or the ovum and the male gamete is called a sperm. These gametes are formed in specialised reproductive structures called gonads.

 

Fertilization :

Fertilization is necessary for sexual reproduction. It is a universal biological process. Sexual reproduction takes place by producing dissimilar gamete that is male. Fertilization occurs by the fusion of that is called fertilization. During sexual reproduction active sperm penetrates into the ovum and the two nucleus fuse together. The is cell is formed by the fusion of nucleus is zygote. It requires sometime for fertilization. Each of the sperm and ovum contains haploid number of chromosome it signifies it carries (one set of chromosome). Due to fertilization zygote is produced, Zygote is a diploid new cell that means it carries two set chromosomes. Maturity of sperm and ovum is the precondition of fertilization. Fertilization is a particular process. It happens only with the matured / full grown sperm and ovum of some species. Generally fertilization is unchangeable. Once an ovum is fertilised it will not fertilize again. On the basis of the place of occurrence, fertilization is divided into two types.


Each of the sperm and ovum contains haploid number of chromosome it signifies it carries (one set of chromosome). Due to fertilization zygote is produced, Zygote is a diploid new cell that means it carries two set chromosomes. Maturity of sperm and ovum is the precondition of fertilization. Fertilization is a particular process. It happens only with the matured / full grown sperm and ovum of some species. Generally fertilization is unchangeable. Once an ovum is fertilised it will not fertilize again. On the basis of the place of occurrence, fertilization is divided into two types.

1. External reproduction
2. Internal reproduction.

 

1 External reproduction:

If the fertilization takes place outside the body of male and female animals, generally in water is known as external reproduction, example in fishes. But exception are there, such as sharks and different fishes.

2. Internal reproduction :

The fertilization which takes place inside the reproductive organ of the female is called internal reproduction. This fertilization occurs introducing sperms of the male into the female reproductive organ. It is one of the characteristics in most of the terrestrial animals.
 

Some basic significance of fertilization:


 

Restoration of diploid chromosomes within the embryo accumulates heriditory characters of both male and female, makes the ovum active for its development. Chromsomes carry the characteristics of both father and mother. These characteristics combine, determine the sex of the embryo. Block picture shows the stapes of gamete formation is give below. For the continuity and restoration of hereditary, reproduction is essential. This process includes formation of embryo and gives birth to offspring. Man is unisexual, so that male and female reproductive organs are present in different individuals.

Concept of reproduction in organisms and its significance


 

Death is inevitable for life if it is born. If only death would have been occurred, once organisms would be extinct. But actually, is not happening because in one hand organisms are dying on the other hand organisms are also reproducing. Reproduction is such a physiological activity through which organisms continue the existence of their offspring by producing their replicas. The process through which organisms produce their offspring is called reproduction.


Reproduction is of two types, such as, asexual and sexual. Generally, in lower organisms, sexual reproduction does not occur but some lower organisms reproduce sexually. Most of the higher plants and all higher animals produce their offspring through sexual reproduction.

In sexual reproduction, two reproductive cells of opposite characters are fused. In this case, one is called male



reproductive cell and the other is called female reproductive cell or egg. Two types of reproductive cells can be produced in the same flower or in the same body. In higher plants, there are two types of reproductive cells produced in the same bodies. They are monoecious plants. When two types of reproductive cells are produced in separate bodies, these plants are called dioecious plants. The precondition of developing of any reproductive cell is that germinal mother cell will have to divide through meiosis.
As a result, the number of chromosomes in a reproductive cell becomes half than that of the mother cell. Later, zygote being divided repeatedly through the process stages of mitosis five stages of mitosis and its significance develops the new body of the newly born organism. In this way, an organism gives birth of many organisms. An organism this way also maintains the flow of its future generations.


If reproduction would not occur in organisms, they would be extinct. From a virus or bacterium up to human beings, all organisms maintain the existence of their species by reproducing their new generations. Which way an organism will accomplish its reproduction depends on the characteristics of the organisms. This is why when a lower organism does its reproduction through cell division then an organism of higher level accomplishes its reproduction through the complex process of sexual reproduction.

Stages of mitosis , Five Stages of mitosis Significance

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Stages of mitosis, Five Stages of mitosis Significance
Stages of mitosis:
Here I shall discuess about the Stages of mitosis, Five Stages of mitosis Significance.  The cell division mitosis is a continuous process. During mitosis, karyokinesis is usually followed by cytokinesis. Karyokinesis and cytokinesis represent the division of nucleus and the division of cytoplasm respectively. Before the starting of the cell division, a cell has to prepare itself. This stage is called interpahse. For the ease of description, the process mitosis can be divided into five stages.

Kinds of Stages of mitosis:


(1) Pro-phase
(2) Prometaphase
(3) Metaphase
(4) Anaphase
(5) Telophase
Now lets we see the details:

(a) Prophase:

This is the first stage of mitosis. At the onset of the stage, nucleus becomes little larger and chromatin fibers start condensing into short, thick and tightly coiled structures called chromosomes. At this stage, chromosome can be seen under compound microscope. Though every chromosome then divides into two sister chromatids, at the centromere each one remains together. As the chromosomes are still in a mess from, it is little tough to count the number of chromosome easily in a cell.

(b) Prometaphase:


At the very early of the stage, spindle apparatus having two poles is developed in plant cells from fiber protein. The middle plane of the spindle apparatus is called equator. Spindle fibers are stretched from one pole to the other. They are called spindle fibers. At this stage kinetochores in centromeres of chromosomes get
attached with some fibers of spindle apparatus.

Kinetochores are protein structures assembled on centromeres and link the chromosomes with mitotic spindles. These fibers are generally called traction fibers. They are also called chromosomal fiber as chromosomes are attached with them. Chromosomes then start assembling on the equatorial plane. The nuclear membrane and nucleolus being disintegrated begin to disappear. In animal cells spindle apparatus is developed from centrioles, and the centrioles remain in two poles with astral rays spreading round from them.

(c) Metaphase:


At the onset of the stage, all the chromosomes complete their assembling at the equator, middle plane from the two poles. The centromere of each chromosome remains on the equator but the two arms take position towards the poles. In this stage, chromosomes look most short and thick. Attraction between chromatids decline and repulsion increases. At the late of the stage, division of centromere starts. Nuclear membrane and nucleolus disappear completely
The significance of mitosis in the living body of organisms is immense. The balance in between the nucleus and cytoplasm of a cell in terms of volume and amount is maintained by the process of cell division mitosis. Through mitosis, the growth in the body multicellular organisms occurs. All the multicellular organisms start their life from a single cell zygote. The repeated division of this single cell produces innumerable cells and thus an organism grows to its complete level. As the number and feature of chromosome remain unchanged in the cells produced through mitosis, growth in organisms takes place systematically. Mitosis plays a role in

Mitosis plays a role in the maintenance of normal size, shape and volume of cells. Unicellular organisms reproduce through mitosis. Mitosis plays an important role in the vegetative reproduction of organisms and increasing the number of reproductive cells. Mitosis is essential in the body of living organisms to form new cells continuously for growth and healing of injuries. The life span of some cells is specific and they are, accordingly, replaced through the process of mitosis. As identical cells are produced through mitosis, qualitative features in the living world remain unchanged. Mitotic errors may result in abnormal mass of cells called tumours, with or without cancer cells.
The question is why meiosis occurs. In process mitosis, the number of chromosomes in the daughter cells remains the same as that of their mother cell. Mitosis is essential for the growth and asexual reproduction of organisms.

In sexual reproduction, the union of male and female gametes is required. If the number of chromosomes in the reproductive cells would be the same as the vegetative cells, the zygote would contain twice number of chromosomes than that of the vegetative cell. Supposing the number of chromosomes in a vegetative and a reproductive cell of an organism is 4. In zygote the number of chromosome would be 8, and so the new organisms will have the body cells with chromosome number 8 and that is twice that of its mother organism. If every life cycle of an organism continues that way, the number of

If every life cycle of an organism continues that way, the number of chromosome would be doubled again and again. In the second chapter, we have learn that chromosomes bear the genes controlling the features of organisms. If the number of chromosome is increased life cycle after life cycle, the offspring will be basically different.
In sexual reproduction, even through the union of male and female gametes, the number of chromosomes remains the same generation after generation as the number of chromosomes becomes half in the reproductive cells than that of the mother cell. When at the time of the development of reproductive cells and in any stage of the life cycle of plants in lower groups, the process meiosis occurs, then the feature of possessing half number of chromosome is called haploid. When the haploid cells are fused, the state of

When the haploid cells are fused, the state of cell having two sets of chromosome is called diploid. As the meiosis cell division occurs, the features in the species of living organisms keep on the same more or less, generation after generation. Meiosis mainly occurs in the primordial germinal cells during the development of gametes. In the anthers and ovules of flowering plants, and in the testes and ovaries of animals meiosis occurs. During the development of pollens from diploid pollen mother cells in mosses and ferns, meiosis occurs in their zygotes.
Two consecutive divisions occur with a cell in the process meiosis. The first and the second division are called meiosis-1 and meiosis-II respectively. In the first division meiosis I, the number of chromosome in a daughter cell becomes half than that of its mother cell, and the second division is simply a mitosis. Because of meiosis, the chromosome number in organisms remains constant.
So generation after generation, the number of chromosomes remains the same in the cells of the body of offspring. Besides, genetic diversity is also found in species of organisms as the exchange of genes occurs during meiosis.
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Cell Division and Types of Cell Division

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Different types of cell division occur in all the types of the organism from unicellular to multi-cellular. Because of a kind of cell division, bodily size of organisms increases and in other type of cell division, reproductive cells are developed and in some other cases organisms multiplies through binary fission. In this chapter, you will know how the different types of cell division occur.


 



Every living body is a cell or cells. Life of every organism starts with a single cell. In fact, every cell is originated from a pre-existing one. The increase of cells in number through division is a very natural and important feature. The body of some organism is composed of a single cell. They are called unicellular organisms, such as bacteria, amoebas, plasmodium etc. These organisms multiply themselves from the division of a single cell. Other organisms are composed of more than one cell.

They are called multicellular organisms. Humans, Mango and Banyan trees etc. are composed of crores of cells. A giant Banyan tree also initiates its structure after the formation of a single cell (zygote by the union of two gametes). After the fertilization of an egg, the structure of a man is accomplish with the crores of cells dividing through the process of cell division. Again, male and female gametes are produced for the emergence of new generations. Cells divide through the process of cell division for the growth and reproduction of organisms

Kinds of cell division:

Three types of cell division take place in living body, such as,
1. Amitosis,
2. Mitosis
3. stages of mitosis five stages of mitosis and its significance

1. Amitosis:


In this division, the nucleus of a cell divides directly into two parts. At the beginning of division, the nucleus elongates with two larger rounded ends and little narrower middle part. The middle part of the nucleus narrowing continuously once splits into two daughter nuclei. By this time cell wall of the cell pinching inward divides the cytoplasm of it into two parts and, ultimately, two daughter cells are produced. This type of cell division is found in bacteria, blue-green algae, yeast etc.

2. Mitosis:


Through this process of cell division, an eukaryotic cell, stage by stage, divides into two identical daughter cells. In this process, nucleus and chromosomes are divided only once and two identical daughter cells are produced with the same type of chromosomes in number, physical and structural features as their mother cell contains.
Mitosis occurs in somatic cells and through this division, as the number of cells increases, the plants and animals grow in length and breadth. The process usually takes place in the body cells of animals and in the meristems of the plant parts growing, such as the tip of stems and roots, plumule and radicle, developing leaves, buds etc.

Stages of mitosis:

The cell division mitosis is a continuous process. During mitosis, karyokinesis is usually followed by cytokinesis. Karyokinesis and cytokinesis represent the division of nucleus and the division of cytoplasm respectively. Before the starting of the cell division, a cell has to prepare itself. This stage is called interpahse. For the ease of description, the process mitosis can be divided into five stages.

4. stages of mitosis five stages of mitosis and its significance

Concept of Biology

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Before reading Concept of Biology, you must know about biology, the branches of Biology and the classification system of Biology. If you know about biology and interested to know the  Concept of Biology, then read this article.

Concept of Biology




In nature, we generally find two types of objects, nonliving things and living organisms. The characteristics of nonliving things are usually discussed in Physics and Chemistry. Biology is a branch of scientific knowledge concerning life and characteristics of organisms. It is one of the oldest branches of natural science. Its background was even created before the origin of life on the earth, and you will learn more about it at your higher classes.


By studying biology, one can acquire interesting knowledge of different plants and animals and human life. In the realm of living creation, the presence of life in a living cell is remarkable. This is why a good command of biology plays an important role in knowing more about the different parts and organ structure of organisms, different chemical activities in them, their adaptation to their environment, their intake of nutrition and reproduction.
The roles of a cell or cells in all steps of life are indisputable. Science has a great contribution in our everyday activities and developing our experience. For our living survival, the fundamental base of biology is inherent in the components of our environment. At the time of walking, our muscles conduct our legs, our nerves move our muscles and the blood circulation in our muscles provides them with oxygen, nutrition and strength.
A single-celled organism also survives, in the same way, using oxygen, nutrition and energy. For the maintenance of biological existence, all living organisms require oxygen and energy. An animal derives this energy from food produced by plants themselves and other sources.
Biology is one of the fundamental branches of science. The term biology is derived from the Greek word, bios, "life" and the suffix -, -logia, "study of." Greek philosopher Aristotle (384BC – 322BC) is called the father of biology. As Biology is the branch of science concerned with the study of life and living organisms, including their structure, function, growth, reproduction, classification, origin and evolution.
The biological species concept defines a species as members of populations that actually or potentially interbreed in nature, not according to the similarity of appearance. Although appearance is helpful in identifying species, it does not define species. To get more idea about biology, read Classification system of biology.

Branches of Biology

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In the previous lesson, I have discussed on biology if you didn't read yet then click here to read - what is biology. Now I shall discuss Branches of Biology which is very important for you. For this, I will say you to read this article attentively. Concept of Biology is another important lesson for you, you can read it.

Based on the type of organism, Biology is divided into two branches
1. Botany.
2. Zoology.

Grounded on the aspect of consideration, there are also two other divisions of biology - as-
1. physical biology.
2. applied biology.

Physical Biology: In the field of physical biology, theoretical concepts are usually discussed. The following subjects are the general fields of its concern.


1. Morphology: The field deals with the form and structure of organisms. It is usually divided into two branches – external and internal morphology. The external description of the body is called external morphology and the internal description of the body is called internal morphology.
2. Taxonomy: Classification of organisms and the principles related to this task are discussed in the field.
3. Physiology: This branch of biology deals with the biochemical activities of different organs of organisms. Besides, detailed description of all the physiological process of organisms is found in it.
4. Histology: The microscopic structure, arrangement and function of plant and animal tissues are studied in this subject.
5. Embryology: The branch of biology discusses the development of embryo of organisms.
6. Cytology: The structure, function and division of an individual cell in a body of organisms are studied in this field of biology.
7. Genetics: The branch of biology deals with genes and heredity.
8. Evolution: The gradual development of life and organisms over successive generations on earth is studied in this subject.
9. Ecology: It is the science of reciprocal relationship between organisms and their environment.
10. Endocrinology: The field of science deals with the study of endocrine glands and hormones secreted by them in a body of organisms.
11. Biogeography: The branch of biology studies the geographical distribution of organisms, past and present, throughout the landscape of planet earth including the knowledge of classifying bio-geographical patterns.
Applied Biology:
Applied subjects related to life are included in this category, and some of them are mentioned below:
1. Palaeontology: Science of the prehistoric life forms and fossils;
2. Biostatistics: Science of statistics of organisms;
3. Parasitology: Science related to parasitism, life process of parasitic organisms and diseases caused by them;
4. Fisheries: Science dealing with fish, harvesting of fish, management and conservation of fish assets;
5. Entomology: Science related to the study of life, merit, demerit, and control of insects including the losses caused by them;
6. Microbiology: Science related to virus, bacteria, fungi and other microorganisms;
7. Agriculture: Science concerning agriculture;
8. Medical Science: Science related to human life, disease, treatment etc.;
9. Genetic Engineering: Science associated with gene technology and its utilities;
10. Biochemistry: Science connected to biochemical process and diseases of organisms;
11. Soil science: Science related to soil, soil structure and soil environment;
12. Environmental Science: Science related to environment;
13. Oceanography: Science related to ocean and its resources;
14. Forestry: Science related to forest, management and conservation of its resources;
15. Biotechnology: Science associated with the technology of utilising of organisms for the benefit of mankind;
16. Pharmacy: Science dealing with technology and industry of medicine;
17. Wildlife: Science related to wild animals;
18. Bioinformatics: Biological information based on computer technology, information on the analysis of cancer, for example.

Hope you have got the clear idea on the Branches of Biology. If you find this is helpful for you then share this lesson on facebook, twitter, and google plus.
Thanks.

Classification System of Biology

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Classification System of Biology To know the Biology classificatio System is very important for every science student for better understanding the subject. About four million of different plant species and thirteen million of animal species have been named and described till today. The number is not yet final because the description of more and more new species is being added to it almost every day.

Classification System of Biology


It is assumed that the number will reach a crore in future when the description of all the organisms will be ended. A large number of organisms are needed to be grouped systematically for the convenience to know, understand and learn them. Many years back natural scientists felt the necessity to classify living world following a natural system. From this very necessity, a distinct branch of biology, taxonomy had emerged.
The aim of classification is only one to know the vast and diverse living world accurately and classify them with little effort in a short period of time. The contribution of Swedish botanist, physician and zoologist Carolus Linnaeus (1707-1778) in the field of taxonomy is more worth mentioning. In 1735 at the age of 28, he took his doctoral degree in medicine at the University of Harderwijk, and in 1741 he was appointed Professor of Medicine at Uppsala University.

Though he was first responsible for medicine-related matters, soon he changed his position with the other Professor of Medicine to become responsible for the Botanical Garden, botany and natural history instead. He thoroughly reconstructed and expanded the Botanical Garden. It was the main field of his intense interest to classify organisms from his botanical and zoological observations that he assembled from his many expeditions.
He classified living world into two kingdoms – Plant and Animal. In 1953 Linnaeus published his book Species Plantarum which is internationally accepted as the starting point of modern botanical nomenclature and in 1958 he released the tenth edition of his book Systema Naturae which established itself as the starting point for zoological nomenclature. He first defined the term genus and species in his book. Based on the observations of size, structure and characteristic, plants and animals are named. On the basis of each other’s similarity and dissimilarity, grouping organisms is called classification.

Aim of Biology Classification System

The aim of classification is to acquire knowledge of every group and subgroup of each organism. To document the accumulated information systematically focusing on the diversity of living organisms, introduce the total knowledge concisely and take proper steps after identifying organisms to conserve them or increase the number of species for the well-being of human beings and the living world are the objectives of classification.
Q: Why classify?
A: Because, it helps to understand things under the complexity of biological diversity One and half million types of organism have been discovered on this planet and it has been estimated that there may be 10-100 million kinds of organisms.
Q: How Classification Began?
A: Classification began By ancient people that observed nature and had a desire to organize the knowledge gained. Classification- the grouping of objects based on similarities ex:: baseball cards, coins, shoes, etc Ancient Chinese classification of dogs Stray Dogs Those have broken flower vase Resemble flies at a distance.

See more at: Branches of Science 

About Biotechnology (General Idea)

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Here I will discuss a short description about biotechnology. Actually, Biotechnology is an applied branch of biology. It has opened new horizons in solving many real problems in different branches of science. To improve human health care, to develop advanced type or crops, to increase the quality and amount of crops, to protect the environment, this technology has opened up doors of immense potentials. In this chapter, we will try to know the facts about this technology briefly.

What is Biotechnology?




The word biotechnology is derived from two words biology and technology. The word biology means special knowledge about organisms and technology means a manner of accomplishing a task specially using technical processes, methods or knowledge. The interrelation between biology and technology is biotechnology. In 1919 Hungarian engineer Karl Ereky first coined the word biotechnology. Through the application of this technology, from a cell of an organism, microorganism or a part of it, any new organism (plant or animal) with new characters is developed or any processed or by-product substance is produced from this organism.

In 1919 Hungarian engineer Karl Ereky first coined the word biotechnology. Through the application of this technology, from a cell of an organism, microorganism or a part of it, any new organism (plant or animal) with new characters is developed or any processed or by-product substance is produced from this organism.

In the advancement of science, biotechnology is not only a new addition. From the dawn of human civilization, man started to apply biotechnology. Man acquired the knowledge of fermentation and brewing about 8000 years ago. In nineteenth century after the discovery of Gregor Johan Mendel’s laws of heredity in the field of genetics, biotechnology started its new advancement. With the continuity of the invention of double helix model of DNA by Watson and Crick in 1953, today’s biotechnology has emerged.

Now a days, tissue culture and genetic engineering from many methods of biotechnology are being used in multidimensional aspects in agriculture and other fields. In order to live well in a healthy and beautiful environment in the present world by ignoring the huge pressure of increasing population, there is no alternative to biotechnology. So the use of biotechnology in every field of life is widespread and massive. By using this technology amount of protein has been increased a lot more than the past. By eating super rice, which is recently invented in this process and rich in iron and beta carotene, we can meet up the want of Vitamin A and iron. Through tissue culture the species of potato, tobacco and banana resistant to virus have been invented. Through biotechnology salinity tolerant and drought resistant species of plants have been invented. Microbes such as bacteria, blue green algae and fungus are being used in producing compost.

By using this technology amount of protein has been increased a lot more than the past. By eating super rice, which is recently invented in this process and rich in iron and beta carotene, we can meet up the want of Vitamin A and iron. Through tissue culture the species of potato, tobacco and banana resistant to virus have been invented. Through biotechnology salinity tolerant and drought resistant species of plants have been invented. Microbes such as bacteria, blue green algae and fungus are being used in producing compost.

By eating super rice, which is recently invented in this process and rich in iron and beta carotene, we can meet up the want of Vitamin A and iron. Through tissue culture the species of potato, tobacco and banana resistant to virus have been invented. Through biotechnology salinity tolerant and drought resistant species of plants have been invented. Microbes such as bacteria, blue green algae and fungus are being used in producing compost.

In order to protect crops from the attack of pests, insecticides bacteria, virus and weeds, microbes and biological agents are being used instead of chemicals and pesticides. An eon making invention is the insulin made by adding human insulin gene to bacteria plasmid and entering them into e-coli bacteria. Interferon is a very precious protein compound which is produced in a very little amount in human body. But this protein is produced so little in human body that it cannot prevent cancer.

Russian scientists have been able to produce interferon by using this technology with the help of e-coli bacteria. With the help of this technology, interferon is now being produced commercially and its price is lower than the past. Alexander Fleming when in 1929 invented antibiotic named penicillin, its productivity was quite low. But through this technology, its production has quite gone up. Each cell in human body carries upto 100000 cells. If error is found in any of these cells, disease can attack human body. So far 3500 such disorders in human body have been known. It is hoped that these disorders will be removed through this technology. Besides, identification of viral diseases, cancer detection, production of antibiotic and vaccine are being done through this Russian scientists have been able to produce interferon by using this technology with the help of e-coli bacteria. With the help of this technology, interferon is now being produced commercially and its price is lower than the past. Alexander Fleming when in 1929 invented antibiotic named penicillin, its productivity was quite low. But through this technology, its production has quite gone up. Each cell in human body carries upto 100000 cells. If error is found in any of these cells, disease can attack human body. So far 3500 such disorders in human body have been known. It is hoped that these disorders will be removed through this technology. Besides, identification of viral diseases, cancer detection, production of antibiotic and vaccine are being done through this

Russian scientists have been able to produce interferon by using this technology with the help of e-coli bacteria. With the help of this technology, interferon is now being produced commercially and its price is lower than the past. Alexander Fleming when in 1929 invented antibiotic named penicillin, its productivity was quite low. But through this technology, its production has quite gone up. Each cell in human body carries upto 100000 cells. If error is found in any of these cells, disease can attack human body. So far 3500 such disorders in human body have been known. It is hoped that these disorders will be removed through this technology. Besides, identification of viral diseases, cancer detection, production of antibiotic and vaccine are being done through this technology.
Some microbes improve the colour, flavour, nutrition of different crops through their effect on them. This technology is used for producing fermented foods in different industries. Besides there are certain microbes turn certain carbohydrates into alcohol through fermentation. By applying the knowledge of biotechnology, enzymes, extracted from microbes, are being used in different industries such as dairy industries, detergent industries and carbohydrate industries. For enhancing the quantity and quality of different medicines, this technology is applied. By using different microbes, energy is produced from biomass and 60% rich methane gas. Daily waste matters, industrial discharges are being degraded by microbes for the improvement of environment.

Rapid afforestation is done by producing large number of saplings of different plants through tissue culture. If bio diversity of any area is destroyed, it has a serious bad effect on the environment of that area. So biotechnology is being used for preservation of biodiversity. For example efforts are being made for rapid propagation of almost extinct plants through tissue culture in order to maintain ecological balance. Different microbes specially bacteria is being used for extracting different elements from the minerals.

For example different bacteria are being used for extracting copper and uranium. Some bacteria keep the environment free from pollution by degrading oil and hydrocarbon from the environment. At present for controlling different pests and insecticides, organic pest control system is being used instead of different chemicals. In organic pest control system different microbes are being used with the help of bio technology which plays an important role in preserving the environment.
For example efforts are being made for rapid propagation of almost extinct plants through tissue culture in order to maintain ecological balance. Different microbes specially bacteria is being used for extracting different elements from the minerals. For example different bacteria are being used for extracting copper and uranium. Some bacteria keep the environment free from pollution by degrading oil and hydrocarbon from the environment. At present for controlling different pests and insecticides, organic pest control system is being used instead of different chemicals. In organic pest control system different microbes are being used with the help of bio technology which plays an important role in preserving the environment.

For enhancing the quantity and quality of different medicines, this technology is applied. By using different microbes, energy is produced from biomass and 60% rich methane gas. Daily waste matters, industrial discharges are being degraded by microbes for the improvement of environment. Rapid afforestation is done by producing large number of saplings of different plants through tissue culture. If bio diversity of any area is destroyed, it has a serious bad effect on the environment of that area.

So biotechnology is being used for preservation of biodiversity. For example efforts are being made for rapid propagation of almost extinct plants through tissue culture in order to maintain ecological balance. Different microbes specially bacteria is being used for extracting different elements from the minerals. For example different bacteria are being used for extracting copper and uranium. Some bacteria keep the environment free from pollution by degrading oil and hydrocarbon from the environment. At present for controlling different pests and insecticides, organic pest control system is being used instead of different chemicals. In organic pest control system different microbes are being used with the help of bio technology which plays an important role in preserving the environment.
So biotechnology is being used for preservation of biodiversity. For example efforts are being made for rapid propagation of almost extinct plants through tissue culture in order to maintain ecological balance. Different microbes specially bacteria is being used for extracting different elements from the minerals. For example different bacteria are being used for extracting copper and uranium. Some bacteria keep the environment free from pollution by degrading oil and hydrocarbon from the environment. At present for controlling different pests and insecticides, organic pest control system is being used instead of different chemicals. In organic pest control system different microbes are being used with the help of bio technology which plays an important role in preserving the environment.
For example efforts are being made for rapid propagation of almost extinct plants through tissue culture in order to maintain ecological balance. Different microbes specially bacteria is being used for extracting different elements from the minerals. For example different bacteria are being used for extracting copper and uranium. Some bacteria keep the environment free from pollution by degrading oil and hydrocarbon from the environment. At present for controlling different pests and insecticides, organic pest control system is being used instead of different chemicals. In organic pest control system different microbes are being used with the help of bio technology which plays an important role in preserving the environment.

Tissue culture: Generally, one or a group of cells of the same type is called tissue. The process of growing a tissue on a nourishing and sterilized medium is tissue culture. Tissue culture is comparatively a new branch of botany. In plant tissue culture, any separate part or part of a part like pollen, apical or lateral bud, node, root is cultured on or in any nourishing and sterilized medium. All the elements for the nutrition and growth of tissue are supplied with the sterilized medium. The part of a plant, being separate with the view of using it in tissue culture, is called ‘explants’. Steps of tissue culture

1. Selection of mother plant:


The healthy, disease resistant plant with high quality is selected for plant tissue culture. 196 Biology

2. Preparation of culture medium:


For the growth of the plant culture, culture media are made by mixing proper amount of essential mineral nutrients, vitamins, phytohormones, sucrose and condensing substance agar to bring the medium to a semisolid state.

3. Establishment of sterilized medium:


Taking the culture medium in a glass container (test tube, conical flask), its opening is usually closed with a cotton plaque. Later in an autoclave machine, keeping it at the temperature of 1210C under 15-lb/sq.-inch pressure for 20 minutes, the medium is sterilized. After the turning of the medium into a cold and semi-solid state, explants are inoculated on it. Then again after closing the mouth or opening the glass container, it is kept in a room with the controlling of light and temperature (25+20 C) for the growth of the explants. In this stage, the tissue placed on the medium through repeated cell division turns directly into a plantlet or callus or a cluster of cells without differentiation.

4. Transfer in root developing medium:


If no root is developed in the plantlets by this time, then after attaining a definite height, shoots are cut and again placed in the root developing medium.

5. Transfer to natural environment or to field level:


After washing with water and putting them outside the room on the tubs, the plantlets are allowed to adapt with the external environment. When the grown up plantlets become fresh and strong, they are once planted in soil in natural environment. Use of tissue culture: By utilizing the tissue culture, now a days in the reproduction of plants and in field of developing new variety, much achievement has been obtained and new horizons have evolved with the vast hopes. From the plant part in a short period of time, innumerable plantlets can be produced with the same characters.

Easily disease free and especially free from viruses, plantlets can be produced. It can be free from the limitation of producing plantlets in the specific season. As the facility of producing plantlets in a short period of time in a very conspicuous place, sufficient number of plantlets can be produced and the problem of storing of seeds can be avoided. The attainment of plantlets of those plants which do not reproduce by seeds and they can be speedily transferred in a short period of time in fresh condition.

Tissue culture technology is well accredited for the production and conservation of the species about to be extinct. The plants, which do not produce endosperm, can be developed directly by culturing their embryo. The rapid multiplication of the plants, which do not reproduce through sexual reproduction or of which rate of natural reproduction is low, can be done by culturing their embryo. Tissue culture technology is being used for the development of the plants of new characters.

French scientist George Morel (1964) proved that it is possible to obtain 40 thousand plantlets from a meristem of the orchid plant named Cymbidium in a year. In natural way, only a limited number of Cymbidium plantlets are produced in a year. In Thailand 50 million plantlets, which are mostly orchids, are produced through tissue culture method in a year. By exporting flowers, the countries like Thailand, Singapore, Malaysia etc. earn every year crores of foreign currency.

In 1952 the scientist named Martin obtained disease free Dalia and Potato plant by culturing meristems of them. Nowadays, it has become a regular practice to make some plants free from viral diseases by culturing their meristems, such as potato tubers. In Malaysia the reproduction of palm oil is done through tissue culture. It is possible to Biology 197 obtain 88 crores of plantlets of Garland of Chrysanthemum from a vegetative part of it through tissue culture. By the hybridization in between different species and varieties of Iris, it has become possible to grow more plantlets of it in a year instead of 2/3 years. Commercially the perfume atar is being produced from the suspension of Jasminum using this technology in many different countries. For the operation of

For the operation of heavy engine such as airplane, rocket etc. a kind of oil from sperm whale is required. This sperm whale is gradually becoming extinct. In an alternative way, this oil is being derived only from a plant named jojoba but this plant does not grow anywhere except in a special desert environment (such as, in Arizona, California), and their reproduction is also time consuming. Through tissue culture, not only the reproduction of this plant has become possible but also it has been changed to a level to adapt to the climate of India. In Bangladesh by this time much more successes have been made through tissue culture, such as it has become possible to produce the plantlets of different orchids grown in the country and in other countries.

Disease resistant and high yielding plantlets of banana, wood apple, jackfruit have been produced. Garland chrysanthemum, gladiolus, lily, garden carnation etc. flower producing plantlets also have been produced. Cadamba, Jarul, epil epil, bakul, teak, nim etc. timber producing plantlets have been produced. Plantlets of different types of pulses, groundnut, jute have also been produced. It has become possible to produce disease free plantlets and seed microtuber of potato applying tissue culture.

Genetic engineering With the view of changing the body of organism in quality by special technique of biotechnology, changing of gene particle in the centre of a cell is called genetic engineering. In other way it can be said, to develop new characters, changing in DNA of any organism is genetic engineering. Genetic engineering is also called recombinant DNA technology. With this technology, the transfer of the desired part of DNA from bacteria to human being, from plant to animal and from animal to plant have become possible. The organism with the new characters is called GMO (genetically modified organism) or GE (genetically engineered) or transgenic.

Stages of the preparation of DNA or GMO
(a) Selection of targetted DNA.
(b) Selection of a carrier so that the transfer of desired segment of DNA becomes possible.
(c) Selection of necessary restriction enzyme (special type of enzyme to cut DNA) to chop the DNA molecule at a particular locus.
(d) Selection of DNA ligase enzyme to join the segments of DNA chopped.
(e) Selection of a host for the replication of the carrier DNA with the segment of desired DNA.
(f) Evaluation of the expression of recombinant DNA prepared with the desired DNA segment.

This technology is being more significantly used by related innovators or investors because in a short period of time very accurately desired characteristic can be transferred by transferring gene through the process of modern biotechnology or genetic engineering.
Genetic engineering is more effective for the development of new crops in comparison with traditional ways of reproduction because transfer of gene is similar or limited to the nearest species through traditional reproduction.

But it is possible to transfer directly one or more genes to nearer or distant species through genetic engineering. Moreover, it requires long time to achieve the desired result through traditional way of reproduction. It is possible to obtain plants or animals or microorganisms with desired characteristics in a very short period of time. In case of traditional reproduction, unexpected genes may be transferred with the desired gene and the transfer of desired gene also remains uncertain. In genetic engineering, there is no possibility of transferring unexpected gene and the transfer of

In genetic engineering, there is no possibility of transferring unexpected gene and the transfer of desired gene is certain. Traditional reproduction is not controlled by any rules and methods of bio-safety, but in case of genetic engineering it is controlled by internationally accredited rules and methods of bio-safety. Toxicity is not tested in traditional reproduction but test of toxicity is done in genetic engineering. Genetic engineering in developing crops: Genetic engineering or recombinant DNA technology is the most modern biotechnology. The main objective of the technology is to develop organisms with new and advanced characters and by which human beings can be benefited surpassingly. By this time notable successes have already been achieved through this technology.

Toxicity is not tested in traditional reproduction but test of toxicity is done in genetic engineering. Genetic engineering in developing crops: Genetic engineering or recombinant DNA technology is the most modern biotechnology. The main objective of the technology is to develop organisms with new and advanced characters and by which human beings can be benefited surpassingly. By this time notable successes have already been achieved through this technology.

Harmful insects resistant varieties of crops have been developed, such as Bt corn, Bt cotton, Bt rice (developed in China) etc. These fruits are resistant to the harmful insects under Lepidoptera and Coleoptera orders. For the insertion of bacterial genes named Bacillus thuringiansis into the crops, these genetically modified crops are designated as Bt corn. Using this technology, virus resistant varieties of crop have been developed, for instance

by transferring gene, tomato mosaic virus (ToMV), tobacco mosaic virus (TMV) and tobacco mild green virus (TMGMV) resistant varieties of crop have been developed. The variety of papaya resistant to ring spot virus (PRSV) has also been developed.

The research is being carried out for the development of late blight resistant variety of potato by transferring late blight fungus resistant gene. Varieties of corn and cotton tolerant to herbicides have been produced by genetic modification. Scientists have become able to develop herbicides tolerant variety of tomato by transferring herbicides tolerant genes into the tomato from a kind of bacteria. This way herbicides tolerant varieties of soybean, corn, cotton, canola etc. have been produced.
The variety of papaya resistant to ring spot virus (PRSV) has also been developed. The research is being carried out for the development of late blight resistant variety of potato by transferring late blight fungus resistant gene. Varieties of corn and cotton tolerant to herbicides have been produced by genetic modification. Scientists have become able to develop herbicides tolerant variety of tomato by transferring herbicides tolerant genes into the tomato from a kind of bacteria. This way herbicides tolerant varieties of soybean, corn, cotton, canola etc. have been produced.

Through genetic engineering more than one trait can be inserted in the same plant. Nowadays, with no trouble this type of transgenic plants is commercially available. For instance, side by side both herbicides tolerant and insect resistant characters have been inserted in corn and cotton. Through genetic change, nutrition value of some crops has been improved. For example, vitamin i.e. beta-carotene gene has been transferred into rice. Taking efforts to add iron in rice is being continued. The attempts are also being made to develop salinity and drought resistant varieties of different crops through genetic modification.

In animals: In livestock, for example transfer of protein C gene has been done to increase protein in cow-milk though still it is in research level. Through genetic modification, genetic changes have been accomplished with the sheep by transferring the growth hormone producing gene from human being to it with the view of increasing its size and meat production. To improve the amount and quality of sheep’s fur, 2 bacterial genes, such as CysE and CysM have been transferred to the genome of sheep.

In healthcare: Hepatitis b-virus vaccine is being produced from yeast through genetic modification. From genetically modified E.coli bacteria and yeast, insulin is being commercially produced for the treatment of the diabetes disease by using the gene, which produces insulin in human body. Human growth hormone and components of the stimulant for accelerated growth of granulocytes macrophage colony are being produced from
genetically modified E.coli bacteria and yeast, and these are respectively being used for dwarfism, viral disease, cancer, AIDS etc.

In improvement of fishing: The areas of petroleum industry and refinery and coal mining are free from pollution because this technology is being used with a view to making the environmental management easy and fast, such as management of industrial wastes and sewage. Dr. M.K. Chakraborty, by performing research on genetic engineering, has developed a variety of Pseudomonas bacteria which is able to disintegrate immediately oil and hydrocarbon in any environment.

If you have about this topics, ask here. https://www.answersmode.com

Special tips for viva voce only for the student and job seekers

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My special tips for viva voce only for the student and job seekers


Viva voce is very important for any kind of jobs it may any company jobs or govt. service. This is the final steps for the examinees. So do not neglect. Viva voce is a bug-bear to the majority of students and interviewers. There are many reasons for deeming it so. But don't be fair because it is not at all an object of fair. It is true that the questions to be asked are uncertain.
Related: Daily writing tips

The examiners have the right to ask you any question. It is impossible to answer every question asked by them. But remember that, they are a human being not a machine and most of them have genuine feelings or sympathy for you. They are not appointed to terrify you by terrible questions. They simply judge your awareness of the subject and want to know how you are fitted to acquire the degree.
The main purpose of viva vice is to test you how you can express what you have learned in the passing years, whether you are acquired with your subject or not, whether you have learned properly or partly, what experienced you have, you are qualified for this job or not, they simply judge your awareness of the subject, want to know how you are fitted to acquired the degree and your expression qualities. Suppose you know, but you can not express it.

If you fail to answer any question, you need not lose heart. Your promptness and preparation will be judged, no matter if you chance to miss answer any question. You should have the courage to say something and express it clearly. If you feel bored with timidity heart, you will forget what you know.

Always remember that- “Nervousness is the worth enemy of your power and expressing your idea.” So leave nervous and be courageous.”
You should also remember that viva board is not a tiger that eats you. They are open heated experienced men. So don’t be fear. Be smart but never smarter. Be courageous but mot audacious. You should have confidence in you. But above all, the questions preparation is of utmost importance. You should go to face viva with a blank head.
We have noticed that most of the students and interviewers blame the examiner for allotting poor marks. If you justify this, you will see that they haven’t well prepared and they can not answer any questions of the examiners. So it should not just or right to blame your examiner because they are not injustice. Remember that they are very experienced person. Remember that, if you really deserve good marks, they will nor, I hope and believe that you will take preparation for the viva voice well and you also get a good mark.
Related: Learn English Grammar
A few words more, when you appear before the board, you should be well dressed. But you need not be snob but a young man with a taste makes a man. Behalf of a man showing your status as a student.



Here is an example of viva voce for the student of honors how you should behave before the interview board:
Student: (Salute them as you deem fit.) may I come in, sir?
Teacher: Yes, sit down. Take your sit. Sign here.
NB: Do not take your sit until their request.
Student: Thanks.
Teacher: Are you adequately prepared to answer the questions?
Student: Yes, sir. I shall try to answer your questions as far as I can do.
Teacher: Which subject do you prefer Mohi Uddin?
Student: As You Like It.
Teacher: Who is William Shakespeare?
Student: William Shakespeare is a great dramatist and poet of English literature. He was born on the 23rd April 1564 in Stratford on Avon, a prosperous town in England.
Teacher: When was “As You Like It” was published?
Student: ‘As You Like It’ was published in 1599 A.D.
Teacher: Who is your favorite poet?
Student: William Wordsworth.
Teacher: Why do you like him?
Student: I like him because he has brought a dynamic change in English poetry.
Teacher: Do know what is mean by dynamic?

NB: if you know the answer, Say “yes sir.” But don’t say : “yea”
If you don’t know the answer, Say “I’m sorry sir.”
If you do not the questions of the examiner say “Pardon me sir” but don’t say “Please repeat again, sir”

Student: I’m sorry, sir, I don’t know the answer to this question. You can ask me another question, please. (You can ask me next question please)
When your test will be over, leave the room politely. But be very particular about your first impression because remember that “The first impression is test long term”

Dear reader, Remember that this is an example of viva board. Take preparation well in your subject and go to viva board with confidence.
Wish you best of luck

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Importance of learning chemistry

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We have understood from our reading of the scope of chemistry that, Now I shall try to discuss Importance of learning chemistry. chemistry is always involved in providing basic human needs like- food, clothing, housing, medication and material of education. It is worth mentioning here that, the belief held by people of different sectors of the society that chemical substance means something hazardous, it is not correct.



Whatever we are eating, such as, rice, pulses, oil, sugar, salt and what we are using like soap, shampoo, detergent powder, medicine etc. are all chemical substances. Aren’t they?

Importance of learning chemistry

The fertilizers and insecticides used in agriculture are all chemical substance. Insects are prevented from destroying the crops by using nsecticides. We are using coil or aerosol to prevent mosquitoes. Soaps, shampoo, detergents are used in cleaning. We take medicines, antibiotics and vitamins to maintain our health. Various types of natural substances like turmeric, henna and artificial cosmetics and colors are used in beautification.





In addition to that we are taking various types of herbal medicines and other materials to protect our health and for beautification. Sometimes inexperienced and dishonest people or farms produce and distribute these materials. Banned chemicals are being used unconsciously or dishonestly to prevent fish and meat from being rotten and to get fruit ripen quickly without considering the damage they cause to human health. Similarly illegal and non-food graded dyes are being using to make foods attractive.

To preserve processed foods for a long time preservatives are used specially in juice, sauce, cake, biscuit etc. Processed food without preservative may be harmful for life, but unfortunately, in most cases, in processing these foods excess amounts of forbidden and non food graded preservatives are uses. On the other hand the heat used in burner for cooking is created by burning of wood or natural gas, where heat, carbon dioxide and other substance are produced from the reaction of oxygen in the air, wood or natural gas.

It is worth mentioning that if wood and natural gas is burnt in presence of insufficient air, a gas called carbon-mono-oxide, which is very harmful for human health may be produced. Besides, on burning of wood or coal harmful carbon particles are produced, we call it soot (kali), when they settle on the wall of the container. In the same way carbon dioxide gas is being produced from industries and automobile engines, which is very harmful to the environment.

Excess fertilizer, pesticide, soap, detergent, shampoo, etc. are polluting the soil and water of rivers and canals. We take the smoke of mosquito coil and aerosols with our inhalation. We use the artificial cosmetics, colours and herbals which reach to the different parts of our body with blood circulation. On the other hand, the roduced carbon dioxide on production of heat or energy go to air and contribute to the increase of the temperature in our atmosphere.

We know, excess use of chemical fertilizer causes harm to the plants even may cause them to die. Similarly, carbon-mono-oxide gas which is very harmful for human is produced on burning of wood or coal with limited supply of air. Excess doses of medicines may even cause people to die. Therefore, it is clear that for good results, the recommended uses of chemical substances are necessary and that can be ensured only by thorough understanding of chemistry.

On the other hand, one can be aware of the risk factors and hazards of various chemical substances from studying chemistry which can build up us as conscious citizens. Along with this we, the users and manufacturers of various products can play important roles in protecting our society and environment by ensuring the proper uses of such products through quality assessment. Therefore, it is clear that, it is very important for everyone to have some knowledge of chemistry. So read chemistry attentively.

Green House

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Green house is a wonderful house invented by modern science. It is very useful for us but it is harmful for our environment and our environmental ecological balance. Now lets we know details about green house , wonderful house of modern science.

What is green house?

Many of you may know what green house is. Green house is a house made of glass. Greenhouse is a building with glass or plastic roof and walls, used for cultivation and protection of tender plants and of plants grown out of season. Greenhouses are designed to control the balance of temperature, moisture, and light to suit the growth requirements for plants as diverse as orchids, cacti, tomatoes, and citrus trees. This house is used for planting trees in it. In cold countries, many plants die due to severe cold. To save and grow necessary plants in severe




cold green house is built. You know that glass is non-conductor of heat. Heat cannot pass through glass easily but light can pass through glass very easily. As the walls and the roof of green house are made of glass, light ray can easily enter the house through the glass. As a result the plants can easily grow inside the green house. On the other hand, outside cold cannot enter into it or the heat inside the house cannot come out. As a result inner side of a green house remains hot. The history of green house is very ancient.

Effect of Green house:

You know that sunlight and heat keep the earth hot. This light and heat come through the atmosphere and warm up the earth's surface. Again it re-radiates some of this heat back into space. For this the earth is not heated too much. Surrounding atmosphere of the earth absorbs some heat and as such the earth can not be very cold by radiating heat. If the quantity of carbon dioxide in the atmosphere is increased, the situation will not remain like this. At the time of radiation of earth's heat much quantity of it is absorbed by the atmospheric carbon dioxide. As a result of increase in atmospheric temperature, the heat of the earth also increases.

The inner heat of the green house can not come out through the glass and it remains hot. Similarly earth's heat can not pass through the carbon dioxide of the atmosphere. As a result the earth becomes warmer. The greenhouse effect has warmed Earth for over 4 billion years. Now scientists are growing increasingly concerned that human activities may be modifying this natural process, with potentially dangerous consequences. Since the advent of the Industrial Revolution in the 1700s, humans have devised many inventions that burn fossil fuels such as coal, oil, and natural gas. These atmospheric gases have risen to levels higher than at any time in at least the last 650,000 years. As these gases build up in the atmosphere, they trap more heat near Earth’s surface, causing Earth’s climate to become warmer than it would naturally.

In harmony with green house the scientists call this natural phenomenon greenhouse effect. The impact of greenhouse effect on human habitation is very dangerous. You know that vast ice is accumulated at the two poles of the earth all the time. If the atmospheric temperature increases, the polar ice will begin to melt and as a result the water level of the seas will increase. Most of the low-laying areas of the earth will go under water though at present these are dry. Moreover many islands, many coastal countries and cities will go under sea water. Most of the areas of Bangladesh will go under deep water of the Bay of Bengal. Lives and habitation will be endangered. But man is responsible for the greenhouse effect. You already know that enhancement of atmospheric carbon dioxide causes green house effect yet men are increasing atmospheric carbon dioxide in various ways.

We generally use firewood, coal, kerosene, petrol, natural gas etc as fuel. We get heat and energy by burning fuel but simultaneously burning fuel also produces huge amount of carbon dioxide. With the increase of population the use of fuel is also increasing. We are destroying forests by cutting down trees to meet the demand of fire wood and timber for various purposes. You know that the vegetation and forests play a very important role for maintaining the ecological balance of nature. Plants use huge quantity of carbon dioxide from the atmosphere for their food preparation and release oxygen into the atmosphere. Due to this plant activity neither oxygen is decreased nor carbon dioxide is increased in the atmosphere. The balance of oxygen and carbon dioxide in nature is maintained.

 


According to the environmental scientists, 25 percent of the total area of a country must be forest, otherwise, it would be difficult to maintain the natural balance. In Bangladesh only about 9 percent land area is forests. In 1974 the forest area was 16.7 percent but this forest is not sufficient for maintaining environmental balance. With the increase of population, this very small amount of forests is also decreasing day by day. Certainly the government has undertaken projects for extensive expansion of new forest areas. The expansion of forest areas cannot cope with the galloping growth of population.

If this situation prevails there will be no forest area in Bangladesh in near future. Scientists call this unnatural heating effect global warming and blame it for an increase in Earth’s surface temperature of about 0.6°C (about 1°F) over the last 100 years. Scientists project global temperatures to continue rising during the 21st century. Warmer temperatures could melt parts of polar ice caps and most mountain glaciers, causing a rise in sea level that would flood coastal regions. Global warming could also affect weather patterns causing, among other problems, prolonged drought or increased flooding in some of the world’s leading agricultural regions.

We use kerosene, petrol, diesel etc. as fuel of vehicles. Coal is used as fuel for running industries and production of electricity. These fuels are derived from fossils and hence these are called fossil fuels. As a result of burning of fossil fuels huge quantity of carbon dioxide is produced. Increase of population increases the number of vehicles and industries for which the quantity of carbon dioxide in the atmosphere also increases.
From this above discussion, you can surely understand that men are polluting the environment in various ways to fulfill their demands. If there is further population growth, more environmental pollution will occur. We all want to live in a pollution free environment. So we all have to be more active to check the environmental pollution. If we can control population growth, it is possible to check environmental pollution to a large extent.

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