Chipko Movement

Dear friends today we are going to remember the movement which shook the minds of peoples regarding environmental protection.

Chipko movement was born in a small hilly village of the upper reaches of Himalayas. The illiterate tribal women commenced this unique moment in December 1972 that became famous as the Chipko Movement. The movement commenced in the Tehri Garhwal district of UP, that actually gathered Momentum in 1978 when the woman faced police firing. It looked as if the movement aimed at saving trees on the Himalayan slopes from the axes of greedy contractors but its objective were broad-based. It questioned the development based on the ruthless butchery of nature to achieve short term gain. It challenged the  old belief that forest mean only Timber, and emphasized their role in making soil, water and pure air which are the basis of life. it was this philosophy which popularised this Movement in many countries. The women of Advani village in Tehri Garhwal had tied the sacred thread around trees, actually hugged the trees, faced police firing in February 1978 and later courted arrest. The movement continued under the leadership of Shri Sunderlal Bahuguna in various villages like Advani and Budhekar of Tehri Garhwal. Mr Bahuguna presented the plan of this movement for protection of soil and water through ban on tree - felling in the Himalayas at the UNEP meeting held in London in June 1982.

" Every standing green tree in the forest is Sentry to protect us from avalanches and landslides, to save our soil and conserve our water. Important gift of tree to us is not Timber, but soil, water and oxygen."

           The Chipko's plan is infact a slogan of planting five Fs - food, fodder, fuel, fibre and fertiliser trees to make communities self sufficient in all their basic needs. It should generate a decentralized 

, self renewing and long-term prosperity. It will protect the environment and bring permanent peace, prosperity and happiness to mankind. Mr Bahuguna along with a team of dedicated workers later under two markers of 300 kilometre from Srinagar to Siliguri. This movement widely spread in different parts of country. Not only this, people from many other countries as France, Germany, Sweden, Switzerland etc. have visited Mr Bahuguna to have accounts and experience of his marches in different parts of the country. In an exhibition, organised on June 5 in Stockholm to mark the World Environment Day, following was written about Chipko Movement:

" A powerful environmental movement has grown up on the slopes of mountains of Himalayas. Villages have created an effective non-violent way to stop the devastation by forest industries. When the axemen comes, the people form ring around the trees - they embrace the trees. This has given the moment its name Chipko Aandolan - 2the tree hugging movement."

खासियत

रत्नापूर नगराचा राजपुत्र अमृत सेन याचं आपल्या प्रजेवर अतोनात प्रेम होतं. तो आपल्या प्रजाजनांच्या मताचा आदर करत असे, त्यामुळे तो अत्यंत लोकप्रिय होता. क्वचित कधीतरी रात्रीच्यावेळी वेषांतर करून तो आपल्या नगरातून फेरफटका मारीत असे. असाच एकदा तो वेषांतर करून फिरत असताना गावाच्या वेशीबाहेर त्याने तीन परक्या माणसांना आपापसात बोलत असताना पाहिलं.

अमृत सेन त्यांच्याजवळ जाऊन म्हणाला,  "तुम्ही कोण आहात?"

त्यावर ते म्हणाले, "आम्ही कश्यप ऋषींचे शिष्य आहोत. आम्ही 14 वर्षे त्यांच्याकडे राहून काही खास विद्या प्राप्त केल्या आहेत. आम्ही या राज्यात प्रथमच येत आहोत."

त्यानंतर पहिला म्हणाला, " मी जमिनीवर पाय आपटून जमिनीच्या पोटात काही दडलेलं असेल तर सांगू शकतो."

त्यावर दुसरा म्हणाला, " मी जमिनीच्या पोटातील खजिना नक्की कुठे दडलेला आहे हे सांगू शकतो."

तिसरा म्हणाला, " मी एखाद्या व्यक्तीला जर केवळ एकदा पाहिलं, तर नंतर ती व्यक्ती कोणताही वेश धारण करून माझ्या समोर आली, तरी मी तिला लगेच ओळखू शकतो."

मग त्या तिघांनी अमृतसरला विचारलं, "तू कोण आहेस?"

अमृत सेन म्हणाला,  "मी आहे एक सामान्य नागरिक पण माझ्याकडे सुद्धा एक गुण आहे."

"तो कुठला?" तिघे एकदमच म्हणाले.

" कोणत्याही व्यक्तीची कोणत्याही संकटातून मी सुटका करू शकतो."

" पण ही विद्या तू शिकला तरी कुठे? तूझे गुरु तरी कोण?"

राजपुत्र म्हणाला, " मला ही विद्या जन्मजातच अवगत आहे मी ही कोणाकडूनही शिकलेलो नाही".

आता त्या तिघांच्या अंगच्या त्या खास गुणांची परीक्षा घेऊन पहायची राजपुत्र अमृत सेनला इच्छा झाली.

ते सर्वजण चालू लागले. चालता-चालता पहिला माणूस रस्त्यात थांबला आणि एका विशिष्ट जागी पाय आपटून म्हणाला, " या ठिकाणी भुयारी मार्ग आहे."

मग सर्वांनी मिळून तिथे जाण्यास सुरुवात केली. खरोखरच या ठिकाणी एक भुयार होतं.  या भुयारातून चालू लागले. भुयारी रस्ता राजाच्या राजवाड्यात जात होता. थोडे अंतर चालून गेल्यावर दुसऱ्याने अचानक एका कोपऱ्यात बोट दाखवले आणि म्हणाला या ठिकाणी गुप्त खजिना आहे.

हे ऐकून राजपुत्र अमृत सेन आश्चर्याने थक्क झाला. तो त्या तिघांकडे बघुन म्हणाला, " तुम्ही इथेच थांबा. मी जरा जाऊन येतो. कदाचित आपण सर्वजण चोर आहोत, असा कोणाचा तरी गैरसमज होऊन बसेल. मी बाहेर पडून पाहून येतो आणि लगेच तुम्हाला येऊन भेटतो."

त्यानंतर तो त्या भूयारा बाहेर पडला आणि त्याने आपल्या शिपायांना बोलावून घेऊन भुयारात उभ्या असलेल्या तिघा माणसांना अटक करण्याची आज्ञा केली. त्यानंतर तो आपल्या राजवाड्याकडे निघून गेला.

दुसर्‍या दिवशी सकाळी त्या तिघा माणसांना दरबारात हजर करण्यात आले. त्या तिघांनी समोर पाहिले तर राजाच्या शेजारच्या सिंहासनावर कालचा तो माणूस बसलेला होता. तो खुद्द राजपुत्र आहे हे पाहून त्यांना धक्का बसला.

हे तिघे अनोळखी वाटसरु राजवाड्याच्या गुप्त खजिन्याच्या जवळपास सापडले, त्यामुळे त्यांना कडक शिक्षा व्हावी अशी राजांनी आज्ञा केली. त्या तिघांनी चोरट्या मार्गाने राजवाड्यात शिरून खजिना लुटण्याचा प्रयत्न केल्याचा आरोप त्यांच्यावर ठेवण्यात आला. परंतु राजा त्यांना सजा ठोठावणार इतक्यात राजपुत्र अमृतसेन त्यांनी हस्तक्षेप केला. तो म्हणाला, "महाराज, हे तिघे चोर नाहीत. उलट खास विद्या अवगत असलेली ही माणसं आहेत. तेव्हा तुम्ही त्यांना सोडावं. त्यांच्या निरपराधी तत्त्वाची ग्वाही मी देतो."

अशाप्रकारे अत्यंत कठीण परिस्थितीतून त्या तिघांची यशस्वीरित्या सुटका करून राजपुत्र अमृत सेनेने आपल्या अंशी खासियत सिद्ध केली.

      (सुधा मूर्ती, अध्यक्षा, इन्फोसिस फाउंडेशन)

Metallurgy

✓physical properties of metals

✓chemical properties of metals

✓physical properties of nonmetals

✓chemical properties of nonmetals

✓reactivity series of metals

✓ ionic compounds and their physical properties

Earth was born about 4.5 billion years ago. Various formative processes have been taking place in the core of the earth and its surroundings since its creation till today. These have resulted in the formation of various ores liquids and gases.

         In the beginning, elements were classified in accordance with their chemical and physical properties into the types of metals, nonmetals and metalloids. This classification of elements is used even today. We are going to get more information about them.

Physical properties of metals

1. Metals are generally found in solid state ( except Mercury and gallium which exist in liquid state at room temperature)

2. Metals have a luster.

3. Metals are good conductors of heat and electricity.

4. Metals have high melting and boiling points.

5. Metals can be beaten into a thin sheet. This property is called as malleability.

6. Metals can be drawn into their thin wires. This property is called as ductility.

7. Metals are sonorous.

Physical properties of nonmetals

1. Under ordinary conditions, non-metals may be solids or gases. (exception bromine is in liquid state)

2. Non metals do not have metallic lustre.  (exception iodine and diamond)

3. Non metals are not ductile and malleable.

4. Non metals are bad conductor of heat and electricity. (Graphite is a good conductor of electricity though it is non metal)

5. The melting and boiling points of nonmetals are low.

Chemical properties of metals

Metals are reactive. They have one, two or three electrons in their valence shell so they easily lose electrons and become positively charged ions. That's why metals are called electropositive elements.

Reactions of metals

a. Reaction of metals with oxygen

                          Metals combine with oxygen on heating in air and metal oxides are formed.

Metal + Oxygen =>  Metal oxide

1. When sodium metal is exposed to air it readily combines to form sodium oxide.

              Na + O2       =>        Na2O

2. when magnesium is burnt in air forms magnesium oxide.

               Mg + O2     =>         MgO

b. Reaction of metals with water

1. Reaction with Na and K

Sodium and potassium metal react rapidly and vigorously with water and liberate hydrogen gas. This is an exothermic reaction.

2Na + H2O  =>  2NaOH +  H2  +  Heat

2K + H2O   =>    2KOH   +   H2 + Heat

2. Reaction with calcium

Calcium reacts with water slowly and less vigorously.

2Ca + 2H2O  => 2Ca(OH)2 + HEAT

3. Aluminium, iron and Zinc do not react with cold or hot water but they react with steam to form their corresponding oxide. Hydrogen gas is liberated in the reaction.

2Al + 3H2O    =>  Al2O3 + 3H2

3Fe + 4H2O      =>   Fe3O4 + 4H2

Zn + H2O        =>    ZnO + H2

c.  Reaction of metals with acids 

Most of the metals react with acids to form their corresponding salt and hydrogen gas is liberated.

When the metals like aluminium, magnesium, iron or zinc are reacted with dilute sulphuric acid or hydrochloric acid, sulphate or chloride salt of metals are formed. Hydrogen gas is liberated in this reaction. The reactivity of metal can be represented as follows

         Mg > Al > Zn > Fe

Mg + 2HCl     =>     MgCl2 + H2

2Al + 6HCl     =>   2AlCl3 + 3H2

Fe  + 2HCl      =>    FeCl3 + H2

Zn + 2HCl.     =>     ZnCl2 + H2

d. Reaction of metals with nitric acid

When copper is treated with concentrated and dilute nitric acid gives different products.

Nitric acid reacts with copper according to the reaction: ...

 4 HNO₃(l) + Cu(s) ==> Cu(NO₃)₂(s) + 2 NO₂(g) + 2 H₂O(l) The copper nitrate salt that forms is a deep blue color. The nitrogen dioxide is a maroon vapor.

e. Reaction of metals with salt of other metals

When iron is reacted with copper sulphate solution iron displaces copper from copper sulphate solution. 

       Fe + CuSO4 ==> FeSO4 + Cu

In this reaction the deep blue colour of copper sulphate solution turns green due to formation of ferrous sulphate.

Reactivity series of metals

The reactivity of all the metals is not same. the arrangement of metals in the increasing or decreasing order of reactivity is called the reactivity series of metals.

According to the reactivity, metals are divided into the following groups.

1. Highly reactive metals

(Potassium, sodium, lithium, calcium)

2. Moderately reactive metals

(Magnesium, aluminium, iron, lead)

3. Less reactive metals

(Copper, Mercury, silver)

f) Reaction of metals with nonmetals

When metal is reacted with non metal the ionic compound is formed.

Example: 

When sodium is reacted with chlorine forms sodium chloride.

2Na + Cl2.    ==> 2NaCl

In this example, sodium chloride ( ionic compound) is formed because sodium loses one electron while chlorine accept one electron.

Chemical properties of nonmetals

Non metals are called as electronegative elements because they form negatively charged ions by accepting electrons.

1. Reaction of non metals with             oxygen

Non metals combine with oxygen to form their corresponding oxides. Generally oxides of nonmetals are acidic in nature but in some cases neutral oxides are also formed.

C + O2 ==> CO2 (acidic)

S + O2 ==> SO2 (acidic)

2C + O2 ==> 2CO (neutral)

2. Reaction of non metals with water

Generally non metals do not react with water (exception halogens).

Chlorine dissolves in water to give hypochlorous acid (HOCl)

Cl2 + H2O ==> HOCl +HCl

3. Reaction of dilute acid with non metals

Generally non metals do not react with dilute acids (exception halogens).

Chlorine reacts with dilute hydrochloric acid to form bromine and HCl

Cl2 + 2HBr ===> 2HCl + Br2

4. Reaction of non metals with hydrogen

Non metals react with hydrogen under certain conditions like temperature pressure and use of catalyst.

S + H2 ==> H2S (hydrogen sulphide)

N2 + 3H2 ===> NH3 (ammonia)

Ionic compounds :

        Compounds formed from cation and anion are called as ionic compounds.

The cation and anion being  positively charged, there is an electrostatic force of attraction between them. This force of attraction between cation and anion is called as the ionic bond.

General properties of ionic compounds

1. Ionic compounds are crystalline solids have a definite shape.

2. They exist in solid state and are hard.

3. they are brittle and can be broken into pieces by applying pressure.

4. They have high melting and boiling points.

5. They are soluble in water but insoluble in organic solvents like kerosene and petrol.

6. They conduct electricity in the molten state and also in an aqueous solution.

[ Generally the ionic compounds have high melting point due to following reasons:-

 1. Ionic compounds are hard due to strong electrostatic force of attraction between oppositely charged ions.

2. Due to very strong electrostatic force of attraction the cations and anions are held tightly together.

3. So large amount of energy is required to overcome this strong electrostatic force of attraction.]

3. Life processes in living organisms part 2

 

  

         Growth, nutrients, respiration, reproduction are essential for living organisms for their survival.

        Reproduction :-

        Formation of new organism of same species by earlier existing organism is called as reproduction. 

                                                                                    OR

 A life process in which a living organism produces another living organism like itself is called 

 as  reproduction.

 

                                Importance of reproduction

         1) It helps to maintain the continuity of the species of organisms.

          2)  It helps to maintain the population of that particular species.

 

                                Types of reproduction

               There are two methods of reproduction in living organisms as follows :

1) Asexual reproduction

2) sexual reproduction

 

          1) Asexual reproduction

The process of formation of new organism by an organism of same species

 without   involvement of gametes is called as asexual reproduction.

OR

 The reproduction which involves only one parent is called as a sexual 

reproduction.This is a fast mode of reproduction. it does not involve two 

parents or two different gametes. The new organism has exact genetic 

similarity with the parent.

 

          2) Sexual reproduction

                 Reproduction with the help of male and female gametes is called sexual reproduction.

 

          A) Asexual reproduction in unicellular organisms :-

 

   1) Binary fission:-

The process in which the parent cell divides to form two similar daughter cells is 

called as binary fission.

1) Binary fission takes place by mitosis or mitosis.

2) It takes place when there are favorable conditions and abundant food supply.

3) Prokaryotes, protest, mitochondria and chlorella perform binary fission.

 Ex- amoeba, paramecium, euglena, chlorella etc.

 

            Based on Axis of fission there are three subtypes of binary fission

            a) Simple binary fission :- The plane of division can be in any direction due to lack of specific 

                                                           shape.  

      Example:- Amoeba

b) Transverse binary fission :- The plane of division is a transverse.    

     Example:- Paramecium

c) Longitudinal binary fission :- The plane of division is in length wise direction.    

    Example :- Euglena

 

          2) Multiple fission

During unfavourable conditions amoeba undergoes multiple fission. Amoeba takes its shadow 

body in  and forms cyst around it. Cyst is a protective covering around plasma membrane. 

Inside the cyst amoeba undergoes repeated nuclear divisions. It is followed by cytoplasmic 

division and manyamoebulae are formed. When favourable conditions appears the cyst breaks

 and many amoebulae are released.

         3) Budding in yeast

1) Yeast is unicellular fungus that performs budding.

2) The parent cell produces two daughter nuclei by mitotic division.

3) This results in a small bulging bud on the surface of parent cell.

4) The daughter nucleus enters the bud. Bud grows and upon becoming big it separates from the  

     parent cell to have independent life as a new Yeast cell.

 

        B) Asexual reproduction in multicellular organisms

 

      1) Fragmentation

Fragmentation is one of the type of a sexual reproduction in multicellular organisms. In this 

type, the body of parent organism breaks up into many fragments and each fragment starts to

 live as an independent new organism. Spirogyra grow up very fast and break up into many 

small fragments when there are favourable conditions. Each newly formed fragment live 

independently as a new spirogyra.

Examples:- spirogyra and sycon.

 

        2) Regeneration

Regeneration is the sexual reproduction in planaria in which the body is broken up into two 

parts and resulting each part regenerates remaining part of the body.

             Example:- Planaria.

 3) Budding in hydra

1)      In case of hydra, there is development of bud on the specific parts  of its body.

2) The bud formation that takes place only under favourable conditions.

3) The bird is formed due to repeated division of regenerative cells of  body wall.

4) Bud grows up progressively and finally forms  a small hydra.

5) Nascent hydrogen gets all the nutrition from parent hydra.

6) When the budding hydra grows sufficiently it separates from parent hydra and grows   

     independently.

 

    4) Vegetative propagation

 

1)      Reproduction in plants with the help of roots stem and leaves and bud is called as vegetative     

propagation.

2) This method of reproduction is only found in plants.

3) Plants like bryophyllum reproduces with the help of buds present on leaf margin.

4) Potato, elephant foot & colocasia propagates with the help of eyes.

5) Carrot and radish perform vegetative propagation with the help of roots.

6) Sugarcane grasses ginger and turmeric vegetative propagation by the bud present on nodes.

 

    5)  Spore formation

1) Mucor reproduces asexually by spore formation.

2) It has a filamentous body having sporangium.

3) The spores are formed in sporangium.

4) When sporangium bursts the sports are released in the air.

5) Spore germinates in moist and warm place and new fungal colony is formed.

     Example:- Mucor, Agaricus, Rhizopus etc.

 

                                                  Sexual reproduction

                    The reproduction which involves male gametes and female gametes is called as sexual

                   reproduction.     OR

                      The reproduction which involves male and female parents is called as sexual         

                    reproduction.

 

 Sexual reproduction involves two main processes that means gamete formation and fertilization.

           1) Gametes formation:-

Gametes are formed by the process of meiosis. In meiosis, the chromosome 

number is reduced to half and diploid (2n) germ cells forms haploid gametes (n).

 

      2) Fertilization:-

                              The union between male gamete and female gamete to form a diploid zygote is 

                            called as  fertilization. The zygote divides mitotically to form embryo. The embryo

                             develops to form new individual.

 

                                                Significance of sexual reproduction

1) In sexual reproduction the recombined DNA is formed.

2) The diversity in living organisms occurs due to genetic variation.

3) Genetic variation helps the organism to adjust with the surrounding environment.

 

                                 Sexual reproduction in plants

 

                                                      Structure of a flower

                                

              1)      Flower is a unit of sexual reproduction in plants. It consists of four floral whorls as calyx, 

                    Corolla,  androecium and gynoecium.

2) The calyx and Corolla are accessory whorls. They are protective in nature.

3) Each part of calyx is called as Petal while each part of corolla is called as sepal.

4) Androecium and gynoecium are necessary whorls because they  participate in sexual 

reproduction.

5) Androecium is a male reproductive part while gynoecium is a female reproductive part.

6) Androecium consists of stamen and filament. Pollen grains are produced due to meiosis in 

anthers.

7) Gynoecium consists of stigma, style and ovary. There are one or more ovules inside the

 ovary.

 

                                                                             Some useful terms

1) Bisexual flower:-

                  A flower in which androecium and gynoecium are present is called as bisexual flower.

                  Examples:- Rose, Hibiscus, Bottle brush plant etc.

 

2) Unisexual flower:-

               A flower in which either androecium or gynoecium is present is called as unisexual flower.

              Examples:- Bitter gourd, papaya etc.

             3) Male flower:-

                                   The flower in which only androecium is present is called as male flower.

             4) Female flower:-

                                        The flower in which only gynoecium is present is called as female flower.

 

       Pollination:

                      The process of transfer of pollen grains from anther to stigma is called as pollination.

                 The pollination is carried out with the help of wind, water, butterfly, bees, animals etc.

 

                                                      Types of pollination

1) self pollination :-

The transfer of pollen grains from the anther to the stigma within the same flower is 

called as self  pollination.

 

2) Cross pollination :-

The transfer of pollen grains from the anther to the stigma of another

 flower borne on two different plants of same species is called as cross 

pollination.

 Fertilization in plants

1.      The pollen grains from the anther are transferred to the stigma of flower by pollination.

2. The pollen grains germinates on the stigma.

3. As a result of germination long pollen tube and two male  gametes are formed.

4. The pollen tube travels through the style to the ovary.

5. Upon reaching there, the tip of the pollen tube bursts & two male gametes are released in

 embryo.

6. One male gamete fuses with the egg cell to form zygote.

7. While other male gamete fuse with polar nuclei forming th endosperm.

8. As two nuclei participate in this process therefore it is called double fertilization.

 

                        Give reasons

             1) Flower is the structural unit of sexual reproduction in plants.

                 * Flower produces male and female gametes in androecium and gynoecium respectively.

                 * The double fertilization also takes place in flower.

                 * Therefore, flower is called the structural unit of sexual reproduction in plants.

 

           2) Fertilization in plants is called double fertilization.

                 * Pollen grain on germination produces two male gametes in pollen tube.

                 * one male gamete fuses with the egg cell to form zygote while the second male gamete 

                    fuses with two polar nuclei forming endosperm.

                 * In this way, two nuclei participate in fertilization process so it is called double fertilization.

 

              Seed germination :-

                                  Seed germination is the process in which the seed develops into a new plantlet.

               In the plants after fertilization the ovary develops into seed and ovary turns into fruit. Seeds 

             fallen on the ground due to bursting of the fruits start germinating. Only under favourable

              conditions in the soil, this germination takes place. The zygote present inside the seed uses 

        food stored in  endosperm of seed and hence develops from further to produce a new plantlet.

 

                                       Sexual reproduction in human being

               Men have XY sex-chromosomes and women have XX sex - chromosomes. Reproductive

              system with specific organs develops in the body of men and women due to these sex 

            chromosomes X chromosomes is present in men and women whereas Y chromosome is present

             in men only.

 

                                         Figure: Human male & female reproductive system

                                                      Human male reproductive system

1) Male reproductive system of humans consists of testes, various ducts and glands.

2) Testes are in pair. Each testis lies in the scrotum which lies outside the abdominal cavity.

3) Testis consists of numerous seminiferous tubules. The germinal epithelium of seminiferous 

    tubules forms sperms by undergoing meiosis.

4) These immature sperms are sent forward through various tubules.

5) This sequence is as follow Rete testis Vas efferentia. Epididymis Vasa deferentia ejaculatory

 duct urethra

6) During travelling sperms becomes mature. They are made capable to perform process of  

    fertilization.

7) Seminal vesicles, single prostate gland and a pair of Cowper's gland secrete their secretions. 

       The secretions and the sperms together form semen.

8) This semen is deposited in the vagina with the help of penis.

 

                        

                                  Human female reproductive system

       1)      All the organs of female reproductive system are located in lower abdomen.

       2)      It includes a pair of ovaries, a pair of fallopian tubes, single uterus and vagina.

      3)   The uterus open out by vagina. In vaginal walls there are Bartholin's glands.

      4)   The free end of fallopian duct is funny like having an opening in the centre.

      5)   The oocyte released from the ovary due to ovulation is picked up by this funnel.

     6)   The other end of fallopian duct opens into uterus. There are cilia on inner surface of oviduct.

     7)   These cilia pushes the oocyte to the uterus through the fallopian duct.

     8)   The fertilization of oocyte can take place only in the middle part of the fallopian duct.

     9)   The lower end of uterus opens into vagina. The contractions of uterus help in the process of  

           parturition.

   10)  Vagina is the birth canal as well as copulatory passage. It is also a passage l for menstrual 

           flow.

 

                                                       Formation of gametes

1)      Sperms and ovum are formed by meiosis

2)      Sperms are produced in testis while ovum is produced in ovaries.

3)      Man can produce sperms from puberty till death.

4)      In case of female, at the time of birth there are 2 to 4 million oocytes in the ovary of 

     female foetus.

5)      From puberty, one mature oocyte is released from ovary every month till the age of 45

       to 50 years.

6)      Menopause is the stop age of function of female reproductive system.

7)      At the age of about 45 to 50 years due to less secretion of female hormones the 

       reproductive system  functions completely stops.

 

                                                        Fertilization in human being

 

                           Union of sperm and ovum to form zygote is called fertilization.

1) Fertilization in humans is internal. The semen is ejaculated in vagina during copulation.

2) In the semen there are few millions of sperms. They swim from vagina through uterus and reach       

     fallopian ducts.

3)      Only one sperm is required for fertilizing a single ovum that female produces.

 

                                                       Development and birth

 

v  The fertilization takes place in fallopian duct.

v  The zygote formed undergoes rapid and repeated mitotic divisions to develop embryo.

v  Embryo is pushed towards uterus. In uterus, it gets implanted &  grows for next 40 weeks

v  The nutrition during this period is provided by placenta which is an organ developed in pregnant mother.

v  After completion of embryonic development, the pregnant mother gives birth to a baby.

 

                                                               Menstrual cycle

 

        Menstrual cycle is the events of cyclic changes that takes place with the interval of 28 to30

        days in  mature women.

 

v  Menstrual cycle is a natural process which is controlled by four hormones.

v  These four hormones are follicle stimulating hormone (FSH), luteinizing hormone (LH), 

    estrogen and progesterone.

v  Under the influence of FSH, one of the several follicles in the ovary starts to develop along with 

    the oocyte present in it.

v  This developing follicle secrets estrogen.

v  Under the influence of estrogen, endometrium (uterine inner layer) grows or regenerates. Mean 

    while developing follicle completes its development.

v  Under the influence of LH, ovarian follicle burst and releases the mature oocyte out of the 

    follicle. This process is called ovulation.

v  The empty ovarian follicle after the ovulation becomes Corpus luteum. Corpus luteum produces 

    hormone progesterone.

v  Endometrial glands secrete their secretion under the effect of progesterone.

v  The oocyte if fertilized is implanted over this endometrium.

v  If it is not fertilized the Corpus luteum become degenerate body called Corpus albicans. The 

    Corpus albicans cannot secret estrogen and progesterone.

v  Due to lack of these hormones, the endometrial layer of the uterus collapses.

v  The tissue debris, along with unfertilized egg is given out through the vagina as menstrual flow.

     This results in bleeding for about five days.

* If women is not pregnant, then this menstrual cycle keeps on repeating with regularity.

 

 

Reproduction and modern technology

          Some couples cannot have children due to various reasons. In women if there are problems 

like irregularity in menstrual cycle, difficulties in oocyte production or implantation in uterus, 

obstacles in the oviduct, etc then she cannot have childrens. Absence of sperms in the semen, slow

 movement of sperms, anomolies in the sperm are the reasons in case of males.

 

Modern technology in reproduction

 

1) In vitro fertilization (IVF) :-

                                                                IVF technique is done when there are problems like less 

sperm count, obstacles in oviduct. In IVF, fertilization is done in the test tube. The embryo formed

 is implanted in uterus of women for further growth.

 

2) Surrogacy :-

In women if there is problem regarding the implantation of embryo in uterus, 

then help of  another woman is taken. This woman is called surrogate mother.

                                                Oocyte from real mother is taken out and   fertilized with sperms

 collected from her husband. These gametes are fertilized outside in a test tube and then the

 fertilized zygote is implanted in the surrogate mother. This technique is called as Surrogacy.

 

3) Sperm bank or Semen Bank :-

If man has problems with the sperm production, then the sperms are collected from the sperm Bank.

 Sperm bank is the place where the donors donate the sperms & such sperms are kept Store. The 

donors Identity is kept secret & he should also be physically and medically fit person.

 

Concept of In Vitro Fertilization (IVF)

v  IVF means in vitro fertilization.

v  By this technique, childless couples can be blessed by their own child.

v  This technique is used for those couples which have problems like less sperm count, obstacle

      in oviduct, etc.

v  In this technique, oocyte from the mother are artificially fertilized with the sperms collected 

    from her husband in a test tube. This fertilization is done in a test tube. So it is called as test 

    tube baby.

v  The embryo formed is implanted in uterus of real mother at appropriate time.

 

 

Twins:-

               Two embryos develop simultaneously in the same uterus and thus two offsprings are    

              delivered  simultaneously. Such offsprings are called as twins.

 

Types of twins

                      There are two main types of twins named as monozygotic twins and dizygotic twins.

             1. Monozygotic twins :-

The twins developed from a single embryo are called monozygotic twins. If within 8 days of zygote formation, cells of that embryo divide into two groups. Each one develops as two separate embryos forming two monozygotic twins. These twins are genetically exactly similar to each other. The gender of the twins is also same.

                                                                   The Siamese twins develop from monozygotic twins, if 

the embryonic cells are divided into two groups 8 days after the zygote formation. These are 

conjoined twins where some parts of body are joined to each other. Also some organs are common

 in Siamese twins.

 

          2. Dizygotic twins:-

When two oocyte are released from the ovary of women and both are fertilized by two separate sperms then there is formation of dizygotic twins.

                                                   These twins are formed due to two embryos that are separately implanted in the uterus. Such twins are genetically different and may be same or different by gender.

 

Reproductive health

v  In India, there is a lack of awareness about reproductive health. Social customs, traditions, 

illiteracy, shyness etc. keep the society under pressure. There is always indifference towards the 

reproductive health of women.

v  Reproductive health can be achieved by keeping genitals clean.

v  The cleanliness and hygiene during menstruation, the cleanliness of genitals and other private

 parts are the aspect of personal hygiene.

v  Therefore, about reproductive health one should have scientific and authentic information.

v  Syphilis and gonorrhea are sexually transmitted or bacterial venral diseases which affect people 

on a large scale.

 

Symptoms of syphilis :-

                Occurrence of chancre (patches) on various parts of body including genitals,

               rash, fever, inflammation of joints, alopecia , etc.

 

Symptoms of gonorrhea :-

v  Painful and burning sensation during urination.

v  Oozing off through penis and vagina.

v  Inflammation of urinary tract, anus, throat, eyes, etc.

 

 

     Population explosion

v  Excessive growth of population within short duration is called as population explosion.

v  The problems due to population explosion are unemployment, decreasing per capita income and increasing loan, stress on natural resources, etc.

v  For population control, therefore in India, family planning is a must.

 

                                   Sex determination in human being

v  In humans, each diploid cell has 22 pair of autosomes and one pair of sex chromosomes

      i.e. (44 + XX or 44 + XY).

v  The genetic makeup of human male is 44  + XY while genetic makeup of female is 44 + XX.

v  Germ cells undergoes meiosis to form haploid gametes having chromosomal combination of

      22 + X or 22 + Y.

v  Male produces two types of sperms, 22 +X and 22+ Y.

v  Female produces only one type of oocyte i.e. 22 + X.

v  Type of sperm of father decides the sex of the child.

v  If X bearing sperm fertilizes the oocyte, the girl is born and if Y bearing sperm fertilizes 

     oocyte, it is a boy.

v  Thus father is responsible for the sex of child in human being.

 

Give scientific reasons :-

 

1. By the age of 45 - 50 women gets menopause.

     By the age of 45 to 50, the secretion of hormones which control the functioning of the 

    reproductive system is reduced gradually and then it stops. This causes end of menstrual cycle.                

     This results into menopause.

 

2. Older mothers have greater chances of conceiving abnormal children.

v  In older women, the oocytes released from ovary during this phase are not normal.

v  Their cell division is abnormal and thus oocyte becomes abnormal too.

v  If such abnormal oocytes are fertilized, the baby is born with many genetic problems like 

     Down's syndrome or Turner's syndrome.

 

3. Indians should follow family planning for controlling the population.

      There is a population explosion in India. This results in to unemployment, decreasing per capita

      income  and increasing loan, stress on natural resources, etc. Only by controlling population,  

      these problems  can be solved. Therefore Indians should follow family planning for controlling

      the population.