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JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life

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JAC Board Class 9th Science Chapter 5 Notes The Fundamental Unit of Life

→ All organisms consist of tiny building blocks which are known as cells. The term ‘cell’ was coined by Robert Hooke from the Latin word ‘cella’ which means a Tittle room’.

→ Cell is the basic structural and functional unit of all organisms. Cell is the lowest level of organisation that is ‘alive’.

→ Cell theory states that: All living organisms are composed of cells. Cell is the fundamental unit of life. All new cells arise from pre-existing cells.

→ Shape and size of cells: Cells vary in shape and size. They may be oval, spherical, rectangular, spindle shaped or totally irregular like the nerve cell. The size of cells also varies in different animals and plants. Most of the cells are very small in size, like red blood cells (RBCs), while some cells are fairly large, like nerve cells. Average size of a cell varies from 0.5 to 20 pm.

→ Cell Structure: Cell is a compound of same basic constituents.
1. Plasma membrane: Plasma membrane is the covering of the cell that separates the contents of the cell from its external environment. It is the living part of a cell. It is a very thin, delicate, elastic and selectively permeable membrane. As it is a selectively permeable membrane, it allows the flow of certain selected substances in and out of the cell. The plasma membrane is flexible and is made up of organic molecules called lipids and proteins. The flexibility of cell membrane also enables the cell to engulf food and other materials from its external environment. Such process is known as endocytosis. It is observed in Amoeba.

JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life

→ Transport of Substances through Plasma Membrane: Substances can pass through plasma membrane by two processes: diffusion and osmosis.
a. Diffusion: It is the process of movement of substances from their higher concentration to their lower concentration. During respiration, CO2 is given out as a waste product and accumulates in higher concentration inside the cell as compared to the outside medium. Due to the difference in concentration inside and outside the cell, CO2 starts moving out of the cell.

b. Osmosis: The movement of water moleculas through a selectively permeable membrane is called osmosis. Osmosis is the movement of water from a region of higher water concentration, through a semi-permeable membrane, to a region of lower water concentration.

→ If the medium surrounding the cell has a higher water concentration than the cell, the cell will gain water by osmosis. Such a solution is known as a hypotonic solution.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 1

  • If the medium has exactly the same water concentration as the cell, there will be no net movement of water across the cell membrane. Such a solution is known as an isotonic solution.
  • If the medium has a lower water concentration than the cell, it will lose water by osmosis. Such a solution is known as hypertonic solution.

→ Cell wall: Cell wall is a non-living, thick and freely permeable covering made up of cellulose. It is available in eukaryotic plant cells and in prokaryotic cells as well. It determines the shape of the cells. It protects the plasma membrane. It prevents desiccation or dryness in cells. It helps in the transport of various substances in and out of the cell.

→ Nucleus: Nucleus is covered by a double¬layered membrane. The fluid inside the nucleus is called nucleoplasm. Nucleus consists of chromosomes which are important for the functioning of a cell. Chromosomes consist of genes which are the carriers of genetic information. Nucleus controls all the metabolic activities of the cell. It is the storehouse of genes. Without nucleus, cell can neither survive nor show specialised activities.

→ Type of cells: The cells can be categorised in two types:

  • Prokaryotic cell: In some organisms, DNA and RNA (genetic substances) are bound by a membrane. This membrane bound nucleus is termed as true nucleus. Prokaryotic cells are the cells in which true nucleus and membrane bound organelles are absent. They are primitive and incomplete cells. Prokaryotes are always unicellular organisms. Bacteria and blue-green algae are examples of prokaryotes.
  • Eukaryotic cell: Eukaryotic cells are the cells in which true nucleus and membrane bound organelles are present. They are advanced and complete cells. Eukaryotes include all living organisms (both unicellular and multicellular) except bacteria and blue green algae.

JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 2

JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life

→ Protoplasm: It is a jelly-like, viscous, colourless semi-fluid substance present in various cell organelles in colloidal form. Protoplasm consists of two parts:

  • Cytoplasm: It is that part of protoplasm which surrounds the nucleus. It contains the various cell organelles.
  • Nucleoplasm: It is that part of protoplasm which is located inside the nucleus.

Protoplasm stores vital chemicals like amino acids, proteins, sugar, etc. It is the site of some metabolic reactions.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 3

→ Cell organelles: These are small membrane bound structures suspended in the cytoplasm. They perform lots of chemical activities to support the structure and functioning of a cell. Some cell organelles are described below:
1. Endoplasmic Reticulum: Endoplasmic reticulum is a mesh-like structure which is composed of numerous tubes. It extends from the plasma membrane to the nuclear membrane. There are two types of endoplasmic reticulum, viz, smooth ER (synthesises lipids, detoxify drugs) and rough ER (synthesises proteins). Rough ER has ribosomes on its surface which give it the characteristic rough appearance.
It serves as the transport channel in the cell. Substances are transported from cell membrane to cytoplasm and to nucleus and vice-versa. ER also serves the role of packing many substances in the cell. It helps in the formation of plasma membrane and Golgi-bodies. Smooth ER helps in synthesis and transport of lipids.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 4
2. Golgi body: The Golgi apparatus, first described by Camillo Golgi, consists of a system of membrane-bound vesicles arranged approximately parallel to each other in stacks called cistemae. The materials synthesised near the ER are packaged and dispatched to various targets inside and outside the cell through the Golgi apparatus. The Golgi bodies store, modify, pack and dispatch the substances. They help in the formation of lysosomes.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 5
3. Lysosomes: Lysosomes are small sac-like structures. They are derived from Golgi complex. Lysosomes contain digestive enzymes. They are found in eukaryotic cells, mostly in animals. Lysosomes help in digestion of foreign substances and wom-out cell organelles. They provide protection against bacteria and vims. They help to keep the cell clean. During the distribution in cellular metabolism, e.g., when they get damaged, lysosomes may burst and the enzymes digest their own cell. Therefore, lysosomes are also known as suicidal bags of a cell.

4. Ribosomes: These are extremely small, dense and round bodies interspersed in the cytoplasm. Ribosomes are made up of ribonucleic acid (RNA) and proteins. In prokaryotic cell, ribosomes are of 70 S type. In eukaryotic cells, ribosomes are of 80 S type. Ribosome is responsible for protein synthesis. They are not membrane bound.

5. Mitochondria: Mitochondria are small sausage-shaped organelles. It is a double-membrane structure. Outer membrane is smooth whereas inner membrane is projected into numerous finger-like structures called cristae. Mitochondria contain their own DNA and ribosomes. They provide energy for the vital activities of living cells. They produce energy due to chemical reactions, in the form of ATPs (Adenosine Triphosphate – energy currency of the cell). Therefore, it is called ‘powerhouse of the cell’.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 6

6. Centrosome and centrioles: Centrosome is found only in eukaryotic animal cells. It is not bounded by any membrane but consists of centrioles. Centrioles are hollow cylindrical structures arranged at right angle to each other and are made up of microtubules. Centrioles help in cell division and also help in the formation of cilia and flagella.

7. Plastids: Plastids are present in most of the plant cells and absent in animal cells. They are usually spherical or discoidal in shape. These are double membrane bound organelles. Plastids also have their own DNA and ribosomes. Plastids are of three types:

  1. Chloroplast: They are green coloured plastids containing chlorophyll. Chloroplasts manufacture food by the process of photosynthesis.
  2. Chromoplast: They are colourful plastids. They provide colour to flowers and fruits.
  3. Leucoplast: They are colourless plastids. They help in the storage of various substances like starch, proteins and fats.

JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life

8. Vacuoles: Vacuoles are fluid filled chambers and are often seen in many cells. Vacuoles are very large in plant cells. A plant cell usually has a single but large central vacuole. Such a vacuole fills almost the entire space inside the cell. Vacuoles are much smaller and few in number in animal cells.
Cell division: A cell divides by one of the following two processes:
i. Mitosis: Each cell divides into two daughter cells and each new cell has same number of chromosomes as the mother cell.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 7
ii. Meiosis: Each cell divides into four daughter cells, each having half the number of chromosomes as the mother cell.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 8

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 4 Structure of the Atom

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JAC Board Class 9th Science Chapter 4 Notes Structure of the Atom

→ Atoms are made up of three fundamental particles or sub-atomic particles called electrons, protons and neutrons. Protons and neutrons of an atom are almost of same mass. The mass of proton is approximately 2000 times as that of an electron.

→ Electron (e): These negatively charged particles were discovered by J.J.Thomson in 1897. In the experiment, a gas at low pressure was taken in a discharge tube made up of glass.
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 1

→ At the ends of the discharge tube, two electrodes were placed, connected to a battery for high voltage supply. The electrode connected to the negative end was known as cathode and that to the positive end as anode.

→ A stream of negatively charged particles was observed coming out of the cathode towards the anode. These particles were called electrons. The collection of negatively charged particles emitted from the cathode in the discharge tube are called cathode rays.

JAC Class 9 Science Notes Chapter 4 Structure of the Atom

→ Proton (p+): In 1886, Goldstein observed in the same experiment, with different situation that, anode emitted positive particles which were called protons.

→ Canal rays: The positively charged radiations produced in the discharge tube from anode are called canal rays.

→ Difference between electron and proton:

ElectronProton
Its mass is negligible.Its mass is 1 unit.
Charge is negative.Charge is positive.
J.J Thomson discovered it.E. Goldstein discovered it.

→ Neutron (n): These neutrally charged particles were discovered by James Chadwick in 1932. Neutrons are present in atoms of all elements except hydrogen.

→ The structure of an atom:
1. Thomson’s Model of an atom: An atom is a positively charged sphere and the electrons are embedded in it. The magnitude of positive and negative charge is same inside an atom, so the atom is electrically neutral.
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 2
2. Rutherford’s α-particle scattering experiment’: α-particles are doubly charged helium ions. Since they have a mass of 4 u, the fast moving α-particles have a considerable amount of energy. A thin gold foil with thickness of about 1000 atoms was taken. A lot of fast moving α-particles were bombarded on this thin gold foil. After passing through the foil, α-particles hit the screen.
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 3

Following are the observations and inferences made:

ObservationInference
a. Most of the α-particles pass through the foil without getting deflected.a. Most of the space inside the atom is empty.
b. Some particles were deflected by small angles.b. Positive charge of the atom occupies very little space.
c. One out of 12,000 particles rebound back.c. All the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.

Rutherford, on the basis of this experiment, suggested ‘the nuclear model of an atom’. According to the nuclear model of an atom:
a. Most of the space inside the atom is empty.
b. At the centre of an atom, a small, heavy, positively charged nucleus is present.
c. Electrons revolve around the nucleus.
d. Total positive charge in nucleus is the same as total negative charge on all electrons of the atom as atom has net zero charge.

JAC Class 9 Science Notes Chapter 4 Structure of the Atom

→ Drawback of Rutherford’s model of an atom: If any charged particle undergoes accelerated motion, it must radiate energy. Therefore, if a charged body (e;) rotates around another charged body (nucleus), it will radiate energy. Due to energy loss through the radiation, speed of electrons will decrease and eventually jt will fall into the nucleus. But such collapse does not occur and atoms are found to be quite stable.

3. Bohr’s Model of Atom: In 1913, Neils Bohr overcame the limitations of Rutherford’s model and proposed a model of atomic structure.
Following are the postulates:
a. Electrons revolve around a centrally located heavy, small and positively charged nucleus in certain discrete orbits.
b. While revolving in discrete orbits, electrons do not radiate energy.
c. These discrete orbits or shells are called energy levels. These orbits or shells are represented by the letters K, L, M, N …
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 4
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 5
→ Distribution of Electrons in Different Orbits: Distribution of electrons in different orbits (shells) is given by Bohr and Bury:
a. Maximum number of electrons present in a shell is given by 2n2 (n = shell number).
For example,
n = 1 (K shell). 2n2 = 2 (1)2 = 2 electrons
b. The maximum number of electrons that can be accommodated in the outermost orbit is 8.
c. Electrons are not accommodated in a given shell, unless the inner shells are completely filled.

→ Atomic Number: The number of protons present in the nucleus of an atom is called its atomic number. It is denoted by Z.

→ Mass Number: Mass number is equal to the number of nucleons present inside the nucleus of an atom. It means, it is the sum of the total number of protons and neutrons of an atom. It is denoted by the letter A.
‘Mass number of element = Number of protons + Number of neutrons’
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 6

→ Isotopes: Isotopes are atoms of same element having same number of protons but different number of neutrons. Isotopes have similar chemical properties but different physical properties.
For example: 126C, 146C

→ Uses of Isotopes:
a. An isotope of uranium (23592C) is used in nuclear power plants to generate electricity.
b. An isotope of cobalt is used in treatment of cancer.
c. An isotope of iodine is used in treatment of goitre.
Isobars: Atoms of different elements having same mass number but different atomic numbers are called isobars.
For example: 4020Ca, 4018Ar

→ Valency: The electrons in the last shell of the atom are called valence electrons. These govern the chemical properties of elements. The number of valence electrons that take part in a chemical reaction is called valency of the atoms.
For example, hydrogen has only one electron in its outermost orbit, thus it requires one more electron to fill its outermost orbit (K shell). For this, hydrogen atom shares one electron with another hydrogen atom and forms Hr

→ When an electron from a higher energy level falls in an orbit of lower energy level, the difference in energy is radiated in the form of electromagnetic radiation or light. This explains why different atoms on heating or under other conditions emit light of different colours.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 3 Atoms and Molecules

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JAC Board Class 9th Science Chapter 3 Notes Atoms and Molecules

→ In 430 B.C., Democritus postulated that matter is made up of very small particles calLed “Atomos’ which means ‘indivisible’. Later, Antoine Lavoisier, from his experimental observations, established the laws of chemical combinations.

→ The Law of Conservation of Mass: This law of conservation of mass states that, the total mass of reactants is equal to the total mass of products.
For example:
A + B → C + D
(Reactants) → (Products)
Total mass of reactants = Total mass of products

→ Law of Definite Proportions: According to the law of definite proportions, in a chemical substance, the elements are always present in definite proportion by mass. For example. in water, the ratio of the mass of hydrogen to the mass of oxygen is always 1: 8.

→ After a series of experiments, Dalton concluded that all matter must be composed of tiny particles, which cannot be further divided. He called them atoms.

JAC Class 9 Science Notes Chapter 3 Atoms and Molecules

→ “The smallest particle of an element is called an atom.”
Atomic radius is measured in nanometer (nm).
1nm = 1 × 109m
1 m = 109nm
Atomic radii of hydrogen atom 1 × 10-10 m

→ Dalton’s Postulates:

  • Matter is made up of atoms.
  • Atoms are indivisible and indestructible.
  • Atoms of a given element are identical in mass and in properties.
  • Compounds are formed by a combination of two or more same or different kinds of atoms and a chemical reaction is a rearrangement of atoms.
  • Atoms of different elements have different masses and chemical properties.
  • Atoms combine in the ratio of small whole numbers to form compounds.
  • The relative number and kind of atoms are constant in a given compound.

→ Elements and symbols: Dalton proposed a scheme of notation to represent elements.
JAC Class 9 Science Notes Chapter 3 Atoms and Molecules 1

→ Symbols for some elements as proposed by Dalton Symbols of some common elements

Name of the elementLatin nameSymbol
Hydrogen–H
Helium–He
Carbon–C
CopperCuprumCu
Cobalt–Co
Chloride–Cl
Cadmium–Cd
Boron–B
Barium–Ba
Bromine–Br
Bismuth–Bi
SodiumNatrium‘ Na
PotassiumKaliumK
IronFerrumFe
GoldAurumAu
SilverArgentumAg
MercuryHydrargyrumHg

→ Molecule: A molecule is a group of two or more atoms that are chemically bonded together and form the smallest part of an element or a compound. This can exist independently and shows all the properties of that substance.

JAC Class 9 Science Notes Chapter 3 Atoms and Molecules

→ Atomicity: The number of atoms constituting a molecule is referred to as its atomicity. Molecules of an element constitute same type of atoms. They may be monoatomic, diatomic or polyatomic.

Name of the elementAtomicityMolecular formula
HeliumMonoatomicHe
NeonMonoatomicNe
ArgonMonoatomicAr
KryptonMonoatomicKr
XenonMonoatomicXe
RadonMonoatomicRn
HydrogenDiatomicH2
ChlorineDiatomicCl2
NitrogenDiatomicN2
PhosphorusPolyatomic (Tetra)P4
SulphurPolyatomic (Octa)S8

→ Ion: Ion is a charged particle and can be positively or negatively charged. A positively charged particle in a molecule is called cation, for example, Na+, Ca2+. An anion is a negatively charged particle in a molecule, for example, F–, Cl–.

→ Valency: The combining capacity of an element is known as valency. The combining capacity of the atoms to form molecules either with same or different elements is defined as valency. Valency is used to find out the number of atoms of an element that will combine with the atom of another element to form a chemical compound.

Every atom wants to become stable. To do so, it may lose, gain or share electrons.
a. If an atom consists of 1,2 or 3 electrons in its valance shell, then its valency is 1, 2 or 3 respectively, and it will lose 1, 2 or 3 electrons respectively.
b. If an atom consists of 5, 6 or 7 electrons in the outermost shell, then it will gain 3, 2 or 1 electron respectively, and its valency will be 3, 2 or 1 respectively.
c. If an atom has 4 electrons in the outermost shell, then it will share these electrons and hence its valency will be 4.
d. If an atom has 8 electrons in the outermost shell, then its valency is 0.
JAC Class 9 Science Notes Chapter 3 Atoms and Molecules 2

→ Variable valency: Some elements show more than one valency, hence, termed as variable valency elements.
For example:
Iron shows
valency II – Fe2+ (Ferrous ion)
valency III – Fe3+ (Ferric ion)

Copper shows
valency I – Cu+ (Cuprous ion)
valency II – Cu2+ (Cupric ion)

JAC Class 9 Science Notes Chapter 3 Atoms and Molecules

→ Chemical Formulae: The chemical formula of a compound is a symbolic representation of its composition.
Rule 1: Cross multiply the valency of elements to form a compound.
JAC Class 9 Science Notes Chapter 3 Atoms and Molecules 3

Rule 2: If compound consists of both metal and non-metal, then metal is written first. For example: In calcium chloride (CaCl2) and zinc sulphide (ZnS), Calcium and Zinc are metals, so they are written first, whereas chloride and sulphide are non-metals.

Rule 3: If a compound is formed with polyatomic ions, then polyatomic ions are written in brackets.
For example: In aluminium sulphate [Al2(SO4)3], the polyatomic sulphate ion, SO42- is enclosed in a bracket before writing the subscript 3.
Here, the bracket with a subscript 3 indicates that three sulphate groups (SO42-) are joined to two aluminium atoms.

Note: Compounds made up of a metal and a non-metal are called salts or ionic compounds. All the above examples are of salts.

→ Mole Concept: The quantity of a substance is expressed in terms of mole. 1 mole is also defined as the amount of substance which contains 6.022 × 1023 units (Avogadro’s number denoted by NA).
For example 1 mole of oxygen atoms represents 6.022 × 1023 atoms of oxygen and 5 moles of oxygen atoms contain 5 × 6.022 × 1023 atoms of oxygen.

→ Molar Mass: The mass of 1 mole of a substance is called molar mass. Atomic mass or molecular mass in gram is equal to molar mass.
For example: Atomic mass of Fe is 56 u. Molar mass of Fe is 56 g.
Atomic mass of H2O is 18 u. Molar mass of H2O is 18 g.
Number of moles = \(\frac{\text { Given mass }}{\text { Molar mass }}\)

For example, number of moles in 122 g of iron will be
\(\frac{\text { Given mass }}{\text { Molar mass }}=\frac{112}{56}\) = 2 × 6.022 × 1023 atoms.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure

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JAC Board Class 9th Science Chapter 2 Notes Is Matter Around Us Pure

→ A pure substance consists of a single type of particles.

→ A mixture has more than one substance (element / compound) mixed in any proportion.

→ Mixtures can be separated into pure substances by appropriate separation techniques.

→ A solution is a homogeneous mixture of two or more substances. The major component of a solution is known as the solvent and the minor one is the solute. For example, sugar dissolved in water or alloy of copper and zinc or ethyl alcohol in water.

  • Mass percentage of a solution
    = \(\frac{\text { Mass of solute }}{\text { Mass of solution }}\) × 100
  • Volume percentage of a solution
    = \(\frac{\text { Mass of solute }}{\text { Mass of solution }}\) × 100

→ Materials which are insoluble in a solvent and have particles which are visible to naked eyes form a suspension. A suspension is a heterogeneous mixture.

→ When solids are dispersed in liquids to form a heterogeneous mixture or an opaque medium, it is called suspension.

JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure

→ Colloidal solutions are heterogeneous mixtures where particles of 1 × 109 to 1 × 10-6 m diameter, called dispersed phase, are distributed uniformly in a solvent, called dispersing medium.

→ Difference between true solutions, suspension and colloidal solutions.

True SolutionColloidalSolutionSuspension
It is a homogeneous mixture of solute and solvent.It appears to be homogeneous but actually it is a heterogeneous mixture of dispersed phase and dispersing medium.It is a heterogeneous mixture.
The solute particles are very small, i.e., less than 109 m in diameter.The solute particles are between 109 and 106 m in diameter.The solute particles are quite large, i.e., larger than 106 m in diameter.
Particles of true solution are not visible to naked eye.Particles are not visible to naked eye but can be seen with ultra­microscope.Particles are big enough to be seen by naked eye.
The entire solution passes through filter paper.The particles can pass through ordinary filter paper.The particles cannot pass through filter paper.
The solute particles do not show Tyndall effect.The particles show Tyndall effect.The particles may or may not show Tyndall effect.
The particles do not settle down.The particles do not settle down.The particles may settle due to gravity.

→ Different Types of Colloids
JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure 1

→ Separation of a mixture can be done by hand-picking, sieving, winnowing, sedimentation, decantation, filtration, evaporation, distillation, fractional distillation, centrifugation, crystallisation and chromatography.

→ A physical change brings about a change in the state of matter without change in the composition or chemical nature of the substance.

→ A chemical change brings about a change in chemical properties of matter because one or more substances are transformed into a new substance.

→ Pure substances can be elements or compounds.

→ An element is a form of matter which cannot be broken down by chemical reactions into simpler substances.

JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure

→ A compound is a substance composed of two or more different types of elements, chemically combined in a fixed proportion.

→ Properties of a compound are different from its constituent elements whereas a mixture shows the properties of its constituting elements or compounds.
JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure 2

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 14 Natural Resources

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JAC Board Class 9th Science Chapter 14 Notes Natural Resources

→ Various material resources derived from the nature for the benefit of mankind are called natural resources.

→ The life supporting zone of earth is called biosphere. It has two components:
a. Biotic components: include all the living things, e.g., forests, animals, humans, etc.
b. Abiotic components: include all the non-living things, e.g., air, water, land, etc.

→ Air: It is an inexhaustible natural resource essential for the sustenance of life. The thick blanket of air that surrounds the earth is called atmosphere. This atmosphere keeps the average temperature of the earth fairly steady.

→ Wind: Moving air is called wind. In coastal areas, the uneven heating of land and water creates winds. During day, the direction of wind is from sea to land (sea breeze) while at night, wind blows from land to sea (land breeze).

JAC Class 9 Science Notes Chapter 14 Natural Resources

→ Rain: When water bodies are heated during the day, water vapour goes into the air. As air rises, it expands and cools forming tiny water droplets? These droplets grow bigger by condensation and fall down as rain.

→ Air pollution: Presence of undesirable and harmful substances in the air causes air pollution. Burning fossil fuels release oxide of nitrogen and sulphur in air which in turn causes acid rain. Smoke and fog in air reduce visibility and form smog.

→ Water: 97% of the water on earth is in oceans and only 3% is fresh water. Of this 3%, only 1 % is available for use and the rest is present in glaciers. Rainwater harvesting improves the availability of fresh water. It is essential for the growth and sustenance of plants and animals.

→ Water pollution: Pollution of water can occur in three ways;
a. by addition of undesirable substances,
b. by removal of desirable substances, and
c. by change in temperature.

→ Chemical fertilizers and pesticides pollute underground water. Chemicals released by industries and water released by dams also pollute water. This also destroys the life- forms in those water bodies.

→ Soil: Soil is formed by various physical, chemical and some biological processes. Sun, water and wind, all contribute to the formation of soil. Some organisms, like lichens, grow on rocks and release chemicals which cause the rock surface to powder down into soil.

→ Soil is composed of different sizes of particles which decide the soil type.

→ Soil pollution: Modem farming practices which use chemical fertilizers and pesticides are harmful for the soil. We should use the soil sustainably and plant trees to prevent soil erosion.

JAC Class 9 Science Notes Chapter 14 Natural Resources

→ Biogeochemical cycles: The cycles in nature which keep replenishing the various natural resources in atmosphere and on the earth’s crust are called biogeochemical cycles.
a. Water-cycle: It is the constant exchange of water among the air, land and sea and between living organisms and their surroundings.
JAC Class 9 Science Notes Chapter 14 Natural Resources 1
b. Nitrogen-cycle: Nitrogen, an important nutrient for all life forms, is circulated through the living and non-living components of the biosphere through various processes like nitrogen fixation (by nitrogen fixing bacteria), ammonification, nitrification and denitrification.
JAC Class 9 Science Notes Chapter 14 Natural Resources 2
c. Carbon-cycle: Carbon is incorporated into life forms by the process of photosynthesis and returns to the atmosphere through respiration, decomposition, combustion, etc.
JAC Class 9 Science Notes Chapter 14 Natural Resources 3
d. Oxygen-cycle: Green plants release oxygen by photosynthesis which is cycled during combustion and respiration.
JAC Class 9 Science Notes Chapter 14 Natural Resources 4

JAC Class 9 Science Notes Chapter 14 Natural Resources

→ Greenhouse effect: Greenhouse gases like CO2, CH4, etc., trap the solar energy and keep the earth warm. This is called greenhouse effect. However, excess of such gases in atmosphere results in heating up of the earth and increase the average temperature across the globe. This is called global warming which has numerous ill-effects like melting of glaciers, floods, draughts, etc.

→ Ozone (O3): Ozone layer is present like a blanket around the earth in the stratosphere. It absorbs the harmful UV radiations from the sun and hence protects us. However, the presence of compounds like CFCs in the atmosphere depletes the amount of ozone. An ozone hole, formed by thinning of ozone, is found over Antarctica. Hence, there is a need to take precautionary measures and lifestyle changes to conserve and procure the nature.

JAC Class 9 Science Notes

JAC Class 10 Social Science Notes Geography Chapter 5 Minerals and Energy Resources

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JAC Board Class 10 Social Science Notes Geography Chapter 5 Minerals and Energy Resources

→ Minerals are an indispensable part of our lives.

  • They are homogeneous, a naturally occurring substance with a definable internal structure.
  • Minerals are obtained from rocks.
  • Certain rocks contain only one mineral while
  • some other rocks contain many minerals.
  • They vary in colour, lustre, density, and hardness.
  • Minerals occur in igneous and metamorphic rocks in cracks, crevices, and joints.
  • The smaller occurrence is called veins and the larger occurrence is called lodes.
  • In sedimentary rocks, minerals occur in layers or beds, e.g., gypsum and potash.
  • Certain minerals occur by the decomposition of surface rocks, e.g., bauxite.
  • Some minerals involve alluvial deposits. These deposits are called placer deposits which are not corroded by water, e.g., gold, silver, etc.
  • Ocean waters contain a vast quantity of minerals e.g., common salt, magnesium, etc.

→ Distribution of Mineral Resources in India

  • India is fortunate to have plenty of minerals but they are unevenly distributed.
  • Peninsular rocks contain reserves of coal, metallic minerals, mica, etc.
  • Sedimentary rocks in western and eastern coasts, Assam and Gujarat have petroleum deposits.
  • Rock system in Rajasthan has non-ferrous minerals.
  • The alluvial plains are devoid of economic minerals.

JAC Class 10 Social Science Notes Geography Chapter 5 Minerals and Energy Resources

→ Ferrous Minerals
Ferrous minerals account for about three- fourths of the total value of the production of metallic minerals. They provide a strong base for the development of metallurgical industries.

→ Iron Ore

  • It is the basic mineral and the backbone of industrial development.
  • Magnetite is the finest iron ore with 70% iron content. Magnetite has magnetic qualities.
  • Haematite is the most important industrial ore in terms of quantity used. It has 50%- 60% iron content.

→ Major Iron Ore Beits in India

  • Odisha-Jharkhand Belt: High-grade haematite is found in the Badampahar mines in Odisha, Singhbhum district in Jharkhand.
  • Durg-Bastar-Chandrapur Belt (Lies in Chhattisgarh and Maharashtra): 14 deposits of super high-grade haematite is found. It is exported to Japan and South- Korea.
  • Ballari-Chitradurga-Chikkamagaluru- Tumakuru Belt: It lies in Karnataka. Kudremukh mines are 100% export unit.
  • Maharashtra-Goa Belt (Lies in Goa and Ratnagiri district of Maharashtra): Though the ores are not of good quality, they are exported through Marmagao port.

→ Manganese:

  • It is used in manufacturing steel.
  • 10 kg of manganese is required to manufacture 1 tonne of steel. Madhya Pradesh (27%) is the largest producer of manganese in India.

→ Non-Ferrous Minerals
Important non-ferrous minerals are: copper, lead, zinc, etc.

→ Copper
India is deficient in the production of copper. They are malleable, ductile and good conductor; used in electrical appliances, electronic and chemical industries. Balaghat mines in Madhya Pradesh, Khetri mines in Rajasthan are leading producers.

JAC Class 10 Social Science Notes Geography Chapter 5 Minerals and Energy Resources

→ Bauxite
Aluminium is obtained from bauxite. Bauxite is strong like iron with extreme lightness. It is malleable and good conductor. 49% of bauxite is produced in Odisha.

→ Non-Metallic Minerals
Mica

  • It splits easily into thin sheets.
  • It is an indispensable mineral used in electric and electronic industries due to its dielectric strength, low power loss factor and resistance , to high voltage.

→ Limestone

  • It is found in sedimentary rocks,’composed in calcium and magnesium carbonates.
  • It is the basic low material for cement industries and essential for iron ore in the refineries.

→ Conservation of Minerals

  • Industry and agriculture are strongly dependent on minerals.
  • The process of mineral formation is very slow in comparison to its present consumption.
  • They are ,finite and non-renewable.
  • Continued extraction from greater depth leads to increasing costs and decreases in quality.
  • Improved technologies need to be evolved to lower the costs.
  • Recycling of metals, using scrap metals and other substances are the steps to consume the minerals for the future.

→ Energy Resources

  • Energy is required for all the activities, i.e., to cook, to provide light and heat, to propel vehicles and to drive machinery. Energy resources are of two types:
  • Conventional Resources: Include firewood, cattle dung cake, coal, petroleum, natural gas and electricity.
    Non-conventional Resources: Include solar, the wind, tidal, geothermal, bio-gas and atomic energy.

→ Coal
Used for power generation, to supply energy to industry and domestic need.

JAC Class 10 Social Science Notes Geography Chapter 5 Minerals and Energy Resources

→ Types of Coal

  • Peat: Decaying plants in swamps produce peat. It has low carbon, high moisture, and low heating capacity.
  • Lignite: It is a low grade brown coal.
    Neyveli in Tamil Nadu has great reserves of lignite. This is also used for generation of electricity.
  • Bituminous: It is buried deep and subjected to increased temperatures. Most popular coal in commercial use.
  • Anthracite: It is the highest quality hard coal.
  • Coal occurs in rock series of 2 main geological ages- Gondwana and Tertiary.

→ Petroleum

  • It provides fuel for heat and lighting, lubricants for machinery and raw materials for industries.
  • Most of the petroleum occurrences are of tertiary age.
  • Mumbai, Gujarat and Assam are major petroleum-producing states in India.
  • Assam is the oldest oil producing state in India.

→ Natural Gas

  • Natural gas is found in association with or without petroleum.
  • It is an environment-friendly fuel because of the low carbon dioxide emission.
  • Large reserves are found in the Krishna- Godavari basin.
  • The 1700 km long Hazira-Vijaypur- Jagdishpur cross-country gas pipeline links Mumbai High and Bassien.

→ Electricity

  • Per capita consumption of electricity is considered as an index of development.
  • It is generated in two ways: Hydro electricity and Thermal electricity.

→ Hydro Electricity:
It is generated by fast flowing water. It is a renewable fuel. In India, there are many multi-projects like Bhakra Nangal, Kopili, Hydel project, etc. Thermal Electricity: It is generated by using coal, petroleum and natural gas. It is a non-renewable fossil fuel.

→ Importance of Non-Conventional Source of Energy

  • Growing consumption of energy resulted in the over dependent on fossil fuels, like coal, petroleum, etc.
  • Rising prices of oil and gas have raised uncertainties about the supply in future.
  • Increasing use of fossil fuels results in the environmental problems.
  • Therefore, there is a pressing need to use renewable resources like solar, wind, tidal energy, etc

→ Nuclear/Atomic Energy

  • It is obtained by altering the structure of atoms.
  • Uranium and Thorium are used for generating electricity.
  • Monazite sands of Kerala are rich in thorium.

JAC Class 10 Social Science Notes Geography Chapter 5 Minerals and Energy Resources

→ Solar Energy

  • Since India is a tropical country, there are enormous possibilities of tapping solar energy.
  • Photovoltaic technology directly converts sunlight into electricity.
  • It will minimize the use of firewood and dung cakes in rural areas.

→ Wind Power
The largest wind farm cluster is located in TamilNadu, between Nagercoil and Madurai.

→ Bio-Gas

  • Shrubs, fast waste animal, and human waste are used to produce bio-gas for domestic use in rural areas.
  • It has higher thermal efficiency.
  • The plants using cattle dung are called ‘Gobar Gas Plants’.
  • It has two benefits: Providing energy for electricity and providing manure.

→ Tidal Energy

  • Oceanic tides are used to generate electricity.
  • Gulf of kachchh in Gujarat, Gulf of Khambhat provide tidal energy.

→ Geothermal Energy

  • Heat and electricity is produced by using the heat from the interior of the Earth.
  • Ground water absorbs the heat from the rocks and becomes hot.
  • There are hundreds of hot springs in India.
  • Two experimental projects have been set up-one in Manikaran (Himachal Pradesh) and the other in Puga valley (Ladakh).

→ Importance of Conservation of Energy Resources

  • Energy is a basic requirement for economic development.
  • Every sector of the national economy, i.e., agriculture, industry, domestic, etc. needs inputs of energy.
  • Consumption of energy has been increasing since independence.
  • Energy conservations and use of renewable energy are the two features of sustainable energy.

JAC Class 10 Social Science Notes

JAC Class 10 Social Science Notes Geography Chapter 4 Agriculture

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JAC Board Class 10 Social Science Notes Geography Chapter 4 Agriculture

→ Two-thirds of the population of India are engaged in agricultural activities.

  • Agriculture is a primary activity, which produces most of the food that we consume.
  • It produces foodgrains and raw material for various industries.
  • Few agricultural products like tea, coffee, spices, etc. are exported.

→ Types of Farming

  • Cultivation methods have changed significantly depending upon the characteristics of physical environment, technological know-how and socio-cultural practices.
  • The types of farming are primitive subsistence farming, intensive subsistence farming and commercial farming.
  • Primitive subsistence agriculture is a ‘slash and bum’ agriculture. When the fertility decreases, the farmers shift and clear a fresh patch of land for cultivation.
  • Practised on small patches of land, with primitive tools and family or community labourers. ‘This type of farming depends upon monsoon, natural fertility of the soil.
  • Intensive subsistence farming is practised in the. are.as of high population pressure on land. It is a labour-intensive farming with high dose of biochemical inputs and irrigation to obtain higher production. The size of land holding is uneconomical but the farmers continue to take the maximum output from the limited land.
  • Commercial farming involves the use of higher doses of modem inputs, like high yielding variety (HYV) seeds, chemical fertilisers, insecticides and pesticides in order to obtain higher productivity. The degree of commercialisation varies from one region to another. Plantation agriculture is a type of commercial farming where a single crop is grown on a large area. It has an interface of agriculture and industry.

JAC Class 10 Social Science Notes Geography Chapter 4 Agriculture

→ Cropping Pattern

  • The three cropping seasons of India are – rabi, kharif and zaid.
  • Rabi crops are sown in winter from October to December and harvested in summer from April to June. Wheat, barley, peas, gram and mustard are some rabi crops. Wheat and other rabi crops are grown in Punjab, Haryana, Himachal Pradesh, Jammu and Kashmir, Uttarakhand and Uttar Pradesh. Availability of precipitation from western temperate cyclone helps in the success of these crops. Green Revolution has been an important factor in the growth of the rabi crops in the states of Punjab, Haryana, western Uttar Pradesh and parts of Rajasthan.
  • Kharif crops are grown with the onset of monsoon and harvested in September- October. Important crops are paddy, maize, jowar, bajra, tur, moong, urad, cotton, jute, groundnut and soyabean. Important rice growing states are Assam, West Bengal, coastal regions of Odisha, Andhra Pradesh, Tamil Nadu, Kerala, Maharashtra, Konkan coast, Uttar Pradesh and Bihar.
  • Zaid season is a short season between the rabi and kharif seasons. Some of the crops grown in this season are watermelon, muskmelon, cucumber, vegetables, sugarcane and fodder crops.

→ Major Crops:

  • Major crops grown are rice, wheat, millets, pulse, tea, coffee, sugarcane, oil seeds, cotton and jute, etc.
  • Rice is a staple crop of majority of people of India. India is the second largest producer of rice after China. It requires high temperature, high humidity and annual rainfall of above 100 cm. In areas of less rainfall, irrigation is required. It is grown in the plains of north and north-eastern India, coastal and deltaic regions. Development of dense canal irrigation and tube wells has enabled rice cultivation in areas of less rainfall.
  • Wheat is the second most important cereal crop. It requires a cool growing season, bright surlshine at the time of ripening, and 50 to 75 cm of annual rainfall equally distributed over the growing season. There are two important wheat growing zones. Major wheat producing states are Punjab, Haryana, Uttar Pradesh, Bihar, Rajasthan and parts of Madhya Pradesh.
  • Millets, also known as coarse grains, are of high nutritious value. Jowar, bajra and ragi are important millets grown in India.
  • Maize is used both as food and fodder. It is a kharif crop. It grows in old alluvial soil. In some states it is grown as rabi crop. Karnataka, Uttar Pradesh, Bihar, Andhra Pradesh and Madhya Pradesh are major maize producing states.
  • Pulses: Iifdia is the largest producer as well as the consumer of pulses in the world. It is a major source of protein in vegetarian diet. Except for arhar, all pulses are leguminous crops and help restore soil fertility by fixing nitrogen. Therefore, they are grown in rotation with other crops. Major pulse producing states are Madhya Pradesh, Uttar Pradesh, Rajasthan, Maharashtra and Karnataka.

→ Food Crops other than Grains

  • Sugarcane is a tropical as well as subtropical crop. It grows well in hot and humid climate, and annual rainfall between 75 cm and 100 cm. It can grow on variety of soil. It requires manual labour from sowing to harvesting. India is the second largest producer of sugarcane after Brazil. The main sugarcane producing states are Uttar Pradesh, Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh, Bihar, Punjab and Haryana.
  • Main oilseeds produced in India are groundnut, mustard, coconut, sesamum, soyabean, castor seeds, cotton seeds, linseed and sunflower seeds. Most of these are edible and used as cooking medium. Some of these are used as raw material in the production of soap, cosmetics and ointments.
  • Tea is a plantation agriculture. It was introduced by the British in India and is a popular beverage. It grows in tropical and sub-tropical climates. It is a labour-intensive industry. Major tea producing states are Assam, hills of Daijeeling and Jalpaiguri districts, West Bengal, Tamil Nadu and Kerala.
  • Coffee is a plantation crop. The Arabica variety initially brought from Yemen is produced in the country. Its cultivation is confined to the Nilgiri in Karnataka, Kerala and Tamil Nadu.
  • India is the second largest producer of fruits and vegetables after China. India produces tropical as well as temperate fruits. Variety of fruits and vegetables is grown all over the country.

JAC Class 10 Social Science Notes Geography Chapter 4 Agriculture

→ Non-Food Crops:

  • Rubber: It grows in tropical and sub-tropical areas. It requires moist and humid climate. It is an important industrial raw material. It mainly grows in Kerala, Tamil Nadu, Karnataka, Garo hills of Meghalaya and Andaman and Nicobar Islands.
  • Fibre crops: Cotton, jute, hemp and natural silk are fibre crops. Cotton, jute and hemp are grown on soil. Natural silk is obtained from cocoons of silkworms fed on mulberry leaves. Rearing of silkworms for the production of silk fibre is known as sericulture.
  • India is the second largest producer of cotton after China. Cotton grows well in black soil of the Deccan plateau. Major cotton producing states are Maharashtra, Gujarat, Madhya Pradesh, Karnataka, Andhra Pradesh, Tamil Nadu, Punjab, Haryana and Uttar Pradesh.
  • Jute is known as the golden fibre. It grows well on the well-drained fertile soils in the flood plains where soils are renewed every year. It is grown in West Bengal, Bihar, Assam, Odisha and Meghalaya. It is used for making gunny bags, coir mats, ropes, yam, carpets and’artefacts. It is losing its market to synthetic fibres, especially the nylon because of its high cost.

→ Technological and Institutional Reforms

  • Sustained uses of land without compatible techno-institutional changes have hindered the pace of agricultural development.
  • Collectivisation, consolidation of land holdings, cooperation and abolition of zamindari, etc. were given priority to bring institutional reforms in the country after Independence.
  • Reforms were introduced by the Government of India in the 1960s and 1970s to improve Indian agriculture.
  • The Green Revolution, which was based on the use of package technology and the White Revolution (Operation Flood) were some of the strategies initiated to improve the lot of Indian -agriculture.
  • However the development was in the selected areas only.
  • Some important steps taken were provision for crop insurance against drought, flood, cyclone, fire, disease, establishment of Grameen banks, cooperative societies, etc.
  • Kissan Credit Card (KCC) and Personal Accident Insurance Scheme (PAIS), Minimum Support Price, special weather bulletins, etc. for farmers were introduced by the Government of India.
  • Bhoodan Gramdan or Bloodless Revolution by Vinoba Bhave was a successful movement.

JAC Class 10 Social Science Notes Geography Chapter 4 Agriculture

→ Impact of Globalisation on Agriculture

  • Though globalisation has been in India since the British rule and even before, it affected the farmers after 1990 when they found it difficult to compete with the developed countries because of the highly subsidised agriculture in those countries.
  • Genetic engineering is recognised as a powerful supplement in inventing new hybrid varieties of seeds. Organic farming is in vogue and encouraged.
  • There should be a change in cropping pattern from cereals to high-value crops to increase earning from agriculture as the economists feel the future of Indian farmers will be bleak, if they continue with foodgrain production on small landholdings.

JAC Class 10 Social Science Notes

JAC Class 10 Social Science Notes Geography Chapter 3 Water Resources

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JAC Board Class 10 Social Science Notes Geography Chapter 3 Water Resources

→ Three-fourth of the earth’s surface is covered with water but only a small proportion of it is freshwater that can be put to use.

  • Freshwater is mainly obtained from precipitation, surface run-off and groundwater.
  • Groundwater isTieing continually renewed and recharged through the hydrological cycle.
  • It is predicted that by 2025 nearly two billion people will live in absolute water scarcity.

JAC Class 10 Social Science Notes Geography Chapter 3 Water Resources

→ Water Scarcity7 and the Need for Water Conservation and Management

  • The availability of water resources varies over time and space because of variations in seasonal and annual precipitation.
  • Water scarcity in most cases is caused by over-exploitation, excessive use and unequal access to water among different social groups.
  • Water scarcity may be due to outcome of large and growing population and consequent gfeater demands for water and unequal access to it.
  • This means higher food grain production.
  • This leads to exploitation of water resources to expand irrigated areas and dry-season agriculture. .
  • Most farmers have their own wells and tube wells in their farms for irrigation to increase their produce. This may reduce the level of groundwater which may adversely affect the availability of water and food security of the people.
  • The existing freshwater resources are under tremendous pressure from the ever- increasing number of industries, multiplying urban centres and urban lifestyles.
  • Scarcity of water may also be due to bad quality of water. Water may be polluted by domestic and industrial wastes, chemicals, pesticides and fertilisers used in agriculture, thus, making it hazardous for human use.
  • It is necessary to conserve and manage water resources to safeguard ourselves from health hazards, to ensure food security, continuation of our livelihoods and productive activities and to prevent degradation of natural ecosystems.
  • Overexploitation and mismanagement of water resources will deplete this resource and cause ecological crisis which may affect our lives deeply.

→ Multi-Purpose River Projects and Integrated Water Resources Management

  • Archaeological and historical records show that in the ancient times construction of sophisticated hydraulic structures, such as dams built of stone rubble, reservoirs, lakes, embankments and canals for irrigation.
  • Traditionally dams were built to impound rivers and rainwater that could be used later for irrigating agricultural fields. These days dams are constructed not only for irrigation, but also for electricity generation, flood control, domestic and industrial water supply, fish breeding, inland navigation and recreation. They are now known as multi¬purpose river projects.
  • The multi-purpose projects were launched after Independence with their integrated water resource management approach with aim of leading the nation to development and progress. Jawaharlal Nehru proclaimed dams as the‘temples of modem India’.
  • However, multi-purpose projects have their disadvantages. These projects lead to sedimentation, which obstructs the natural flow, resulting in rockier stream beds; make it difficult for aquatic fauna to migrate, especially for spawning; submerge the floodplains and vegetation, leading to decomposition of soil over a period of time.
  • Multi-purpose projects also lead to large- scale displacement of local communities, tearing them off of their livelihood and resources. Social movements like Narmada Bachao Andolan and Tehri Dam Andolan resist these projects.
  • Irrigation has changed the cropping pattern as farmers have shifted to water-intensive cropping causing salinisation of soil.
  • Inter-state water disputes have increased.
  • These dams have triggered floods due to sedimentation in the reservoif, induced earthquakes, and caused land degradation, water-borne diseases, pests and pollution due to excessive use of water.

JAC Class 10 Social Science Notes Geography Chapter 3 Water Resources

→ Rainwater Harvesting:

  • Water harvesting is a viable alternative, both socio-economically and environmentally as compared to the multi-purpose projects.
  • In ancient India, there had been sophisticated hydraulic systems of rainwater harvesting.
  • People had in-depth knowledge of rainfall regimes, wide range of techniques to harvest rainwater, river water, flood water and recharge the groundwater sources, keeping in mind the ecological conditions and their water needs.
  • In the mountainous regions, people built channels like ‘kuhls’ or ‘guls’ for agriculture. In Bengal, people developed inundation channels to irrigate their fields.
  • In the arid and semi-arid regions ofRajasthan, farmers converted their agricultural fields into rain-fed storage structures that allowed the water to stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan. In Bengal, people carved out inundation channels to irrigate their fields.
  • In Bikaner, Phalodi and Banner, Rajasthan, people had well-structured rooftop rainwater harvesting system which were connected with underground tanks or tankas for storing water also called ‘Palar pani’.
  • This water was used during the dry season when there was scarcity of water.
  • Today, in western Rajasthan plenty of water is available due to the perennial Indira Gandhi Canal.
  • Gendathur, a remote backward village of Mysuru, Karnataka has earned the rare distinction of being rich in rainwater by practising rooftop rainwater harvesting system.
  • Tamil Nadu is the first state to make rooftop rainwater harvesting compulsory to all houses across the state. There are legal provisions to punish the defaulters.
  • Shillong in Meghalaya, 200-year old bamboo drip irrigation system is followed for irrigating plants.

JAC Class 10 Social Science Notes

JAC Class 10 Social Science Notes Geography Chapter 2 Forest and Wildlife Resources

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JAC Board Class 10 Social Science Notes Geography Chapter 2 Forest and Wildlife Resources

→ We share this planet with millions of other living beings, starting from micro¬organisms and bacteria, lichens to banyan trees, elephants and blue whales. This entire habitat that we live in has immense biodiversity. We humans along with all living organisms form a complex web of ecological system in which we are only a part and very much dependent on this system for our own existence.

→ Forests plays a key role in the ecological system as these are also the primary producers on which all other living beings depend.

→ Biodiversity or Biological Diversity is immensely rich in wildlife and ‘cultivated species, diverse in form and function but closely integrated in a system through multiple network of interdependencies.

→ Flora and Fauna in India

  • India is one of the world’s richest countries in terms of its vast array of biological diversity, and has nearly 8 per cent of the total number of species in the world (estimated to be 1.6 million).
  • Some estimates suggest that at least 10 per cent of India’s recorded wild flora and 20 per cent of its mammals are on the threatened list. Many of these would now be categorised as ‘critical’, that is on the verge of extinction like the cheetah, pink-headed duck, mountain quail, etc.

Based on the International Union for Conservation of Nature and Natural Resources (IUCN), we can classify as follows:
(a) Normal Species: Species whose population levels are considered to be normal for their survival, such as cattle, sal, pine, rodents, etc.

(b) Endangered Species: These are species which are in danger of extinction. The survival of such species is difficult if the negative factors that have led to a decline in their population continue to operate. The examples of such species are black buck, crocodile, Indian wild ass, Indian rhino, lion tailed macaque, sangai (brow antlered deer in Manipur), etc.

(c) Vulnerable Species: These are species whose population has declined to levels from where it is likely to move into the endangered category in the near future if the negative factors continue to operate. The examples of such species are blue sheep, Asiatic elephant, Gangetic dolphin, etc.

(d) Rare Species: Species with small population may move into the endangered or vulnerable category if the negative factors affecting them continue to operate. The examples of such species are the Himalayan brown bear, wild Asiatic buffalo, desert fox and hombill, etc.

(e) Endemic Species: These are species which are only found in some particular areas usually isolated by natural or geographical barriers. Examples of such species are the Andaman teal, Nicobar pigeon, Andaman wild pig, mithun in Arunachal Pradesh.

(f) Extinct Species: These are species which are not found after searches of known or likely areas where they may occur. A species may be extinct from a local area, region, country, continent or the entire earth. Examples of such species are the Asiatic cheetah, pink head duck.

JAC Class 10 Social Science Notes Geography Chapter 2 Forest and Wildlife Resources

→ Reasons for Depletion of Biodiversity (Flora and Fauna)

  • The greatest damage inflicted on Indian forests was’ during the colonial period due to the expansion of the railways, agriculture, commercial and scientific forestry and mining activities.
  • Even after Independence, agricultural expansion continues to be one of the major causes of depletion of forest resources.
  • Large-scale development projects have also contributed significantly to the loss of forests. Since 1951, over 5,000 sq km of forest was cleared for river valley projects.
  • Mining is another important factor behind deforestation. The Buxa Tiger Reserve in West Bengal is seriously threatened by the ongoing dqlomite mining.
  • Habitat destruction, hunting, poaching, over-exploitation, environmental pollution, poisoning and forest fires are factors, which have led tcfthe decline in India’s biodiversity.
  • Other important causes of environmental destruction are unequal access, inequitable consumption of resources and differential sharing^ of responsibility for environmental well-being. Over-population in third world countries is often cited as the cause of environmental degradation.

→ Methods or Measures to Conserve Biodiversity

  • Deforestation should be totally stopped. Instead, trees should be replanted on degraded land and on land where forest had been cleared earlier.
  • People should initiate movement against tree cutting such as ‘Chipko Movement’.
  • ‘Van Mahotsava’ and similar kind of events should be celebrated to conserve forest.
  • Mass media, e.g., TV, radio, newspapers, etc., should be used for creating awareness.
  • Govt, should pass and implement strict laws like Indian Wildlife Protection Act – 1972 against illegal cutting of trees, hunting and poaching.
  • Various projects like Project Tiger, Project Rhino, etc., should be started.
  • More National Parks, Wildlife Sanctuaries, Biosphere Reserve should be identified.
  • There should be frequent survey and census to count population of different species found in the forest.

→ Short Note on Project Tiger:
Tiger is one of the most important species among fauna. It was estimated that population of tigers has decreased rapidly in the last one hundred years. Major reasons identified behind depletion of tiger were hunting and poaching, deforestation, depletion of prey etc. Project Tiger was started in 1973 to protect the tigers from extinction. There are 50 tiger reserves in India. Project Tiger has successfully improved the condition.

→ Types of Forests in India
(a) Reserved Forests: More than half of the total forest land has been declared reserved forests. Reserved forests are
regarded as the most valuable as far as the conservation of forest and wildlife resources are concerned.
(b) Protected Forests: These forests are protected from further depletion. About one-third forests comes under protected forests.
(c) Unclassed Forests: These forests belong to government, private individuals and communities.

→ Distribution of Forest in India

  • Only 24.16% land is under forest in India. Distribution of forest in India is not uniform.
  • Madhya Pradesh has the largest area under pennanent forests with 75% of its total forest area. The other states like Jammu and Kashmir, Andhra Pradesh, Uttaranchal, Tamil Nadu, Kerala, West Bengal and Maharashtra have large percentage of reserved forests.
  • States like Bihar, Haryana, Punjab, Himachal Pradesh, Orissa and Rajasthan have large areas of protected forests.
  • All the north-eastern states and parts of Gujarat have large percentages of unclassed forests which are managed – by local communities.

JAC Class 10 Social Science Notes Geography Chapter 2 Forest and Wildlife Resources

→ Role of Community (local people) in Conserving Forest and Wildlife

  • Community or local people are very helpful in conserving biodiversity i.e. plants and animals. Many communities live in the forest. Forest is home of many traditional people.
  • In Rajasthan, local people came forward to stop.mining activities to protect Sariska Tiger Reserve.
  • People of five villages in the Alwar district of Rajasthan have declared 1200 hectares of land as ‘Bhairodev Dakav Sonchuri’ in which hunting is not allowed.
  • In Jharkhand, Munda tribe worship Mahua and Kadamba trees and they protect them.
  • Famous Chipko Movement in Himalayas was started by local community only. Beej Bachao Andolan in Tehri and Navdanya have produced crops without the use of synthetic chemicals.
  • Joint Forest Management [JFM] started in Odisha is good method of involving local community in management and restoration of degraded forest.

JAC Class 10 Social Science Notes

JAC Class 10 Social Science Notes Geography Chapter 1 Resource and Development

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JAC Board Class 10 Social Science Notes Geography Chapter 1 Resource and Development

→ Everything, that is available in our environment and can be used to satisfy our needs, is termed as resources, provided, it is technologically accessible, economically feasible and culturally acceptable.

→ Resources are a function of human activities. Human beings themselves are essential components of resources.

→ Types of Resources: Resources can be classified into different categories:
(a) On the basis of origin: Biotic and abiotic.
(b) On the basis of exhaustibility: Renewable and non-renewable.
(c) On the basis of ownership: Individual, community, national and international.
(d) On the basis of status of development: Potential, developed stock and reserves.

→ Resource Planning: This is a technique or skill of proper utilisation of resources.

JAC Class 10 Social Science Notes Geography Chapter 1 Resource and Development

→ Resource Planning in India: Resource planning ,is a complex process which involves:
(a) Identification and inventory of resources across the regions of the country. This involves surveying, mapping and qualitative and quantitative estimation and measurement of the resources.
(b) Evolving a planning structure endowed with appropriate technology, skill and institutional set up for implementing resource development plans.
(c) Matching the resource development plans with overall national development plans.

→ Conservation of Resources: Irrational consumption and over-utilisation of resources may lead to socio-economic and environmental problems. To overcome these problems, resource conservation at various levels is important.

→ Land Resources:

  • India has land under variety of relief features like mountains, plateaus, plains and islands. About 43 per cent of the land area is plain, which is either used for agriculture or industry. 30 per cent of the total surface area of the country are mountains and ensure perennial flow of some rivers, provide facilities for tourism and ecological aspects.
  • The plateau region accounts for about 27 per cent of the area of the country. It possesses rich reserves of minerals, fossil fuels and forests.
  • The use of land is determined both by physical factors such as topography, climate, soil types and human factors such as population density, technological capability and culture and tradition, etc.

→ Land Degradation and Conservation Measures: Human activities such as deforestation, overgrazing, mining and quarrying have contributed significantly in land degradation. Measures like afforestation, proper management of grazing, planting of shelter belts of plants, control on overgrazing, etc., can help to reduce land degradation in dry areas.

→ Soil as a Resource: Soil is a living system. It takes millions of years to form soil upto a few cm in depth. The important factors in the formation of soil are relief, parent rock or bed rock, climate, vegetation and other forms of life and time.

→ Types of Soil
(a) Alluvial soil: Alluvial soil as a whole is very fertile. Mostly this soil contains adequate proportion of potash, phosphoric acid and lime which are ideal for the growth of sugarcane, paddy, wheat and other cereal and pulse crops. Due to its high fertility, regions pf alluvial soils are intensively cultivated and densely populated.

(b) Black soil: This soil is black in colour and is also known as regur soil. Black soil is ideal for growing cotton and is also known as black cotton soil. Black soil consists of higher proportion of clay and thus can retain moisture for a long time. The soil is sticky and when wet, it is difficult to work unless tilled immediately after the monsoon.

(c) Red soil: This soil develops a reddish colour due to diffusion of iron in crystalline and metamorphic rocks. Red soil develops on crystalline igneous rocks in the areas of low rainfall.

(d) Laterite soil: Laterite soil develops in the areas with high temperature and heavy rainfall. This is the result of intense leaching due to heavy rain. This soil is very useful for growing tea and coffee.

(e) Arid soil: Arid soil ranges from red to brown in colour. It is generally sandy in texture and saline in nature. In some areas Hie salt content is very high and common salt is obtained by evaporating the water.

(f) Forest soil: This soil is found in the hilly and mountainous areas where sufficient rain forests are available.

JAC Class 10 Social Science Notes Geography Chapter 1 Resource and Development

→ Soil Erosion and Conservation: Some human activities such as deforestation, overgrazing, mining and quarrying have contributed significantly in land degradation.

→ Some methods of soil conservation are:
(a) Afforestation
(b) Controlled grazing
(c) Contour Ploughing
(d) Terrace Farming
(e) Strip Cropping
(f) Shelter belts
(g) Crop Rotation

→ Biotic: These are obtained from biosphere and have life.

→ Abiotic: Those things which are composed of non-living things.

→ Renewable Resources: The resources which can be renewed or reproduced.

→ Non-Renewable Resources: These resources take millions of years in their formation.

→ Individual Resources: Resources which are owned privately by the individuals.

→ Community Owned Resources: Resources which are accessible to all the members of the community.

→ National Resources: Resources belonging to the nation.

→ International Resources: International institutions which regulate some resources.

→ Potential Resources: Resources which are found in a region, but have not been utilised.

→ Developed Resources: Resources which are surveyed and their quality and quantity have been determined for utilisation.

→ Sustainable Development: Sustainable economic development means ‘development should take place without damaging the environment.

→ Soil Erosion: The removal of top fertile soil cover due to various reasons like wind, glacier and water.

JAC Class 10 Social Science Notes

JAC Class 10 Social Science Notes Civics Chapter 8 Challenges to Democracy

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JAC Board Class 10 Social Science Notes Civics Chapter 8 Challenges to Democracy

→ Thinking about challenges

  • Democracy is the dominant form of government in the contemporary world. It does not face a serious challenge or rival.
  • The promise of democracy is far realized anywhere in the worlds
  • Democracy does not have a challenger, but that does not mean that it does not face any challenges.
  • A challenge is not just any problem. We usually call only those difficulties a ‘challenge’ which is significant and which can be overcome.
  • A challenge is a difficulty that carries within it an opportunity for progress.
  • The first challenge is a foundational challenge, of making the transition to democracy and then instituting democratic government.
  • The second challenge is the challenge of expansion. This involves applying the basic principle of democratic government across all the regions, different social groups and various institutions.
  • The third challenge is of deepening of democracy is faced by every democracy in one ‘form or another. This involves the strengthening of the institutions and practices of democracy.

JAC Class 10 Social Science Notes Civics Chapter 8 Challenges to Democracy

→ Thinking about political reforms

  • Generally, all the suggestions or proposals about overcoming various challenges to democracy are called ‘democratic reform’ or ‘political reform’.
  • If all the countries do not have the same challenges, it follows that everyone cannot follow the same recipe of political reforms.
  • We can develop some proposals for reforms at the national level.
  • But the real challenge of reforms may not lie at the national level.
  • Instead of that let us think of some broad guidelines that can be kept in mind while devising ways and means for political reforms in India:
  • It is very tempting to think of legal ways of reforming politics, to think of new laws to ban undesirable things. But this temptation needs to be resisted.
  • Any legal change must carefully look at what results it will have on politics. Sometimes the results may be counter-productive.
  • Democratic reforms are to be brought about principally through political practice. Therefore, the main focus of political reforms should be on ways to strengthen democratic practice.
  • Any proposal for political reforms should think not only about what is the good solution but also about who will implement it and how.
  • Let us keep these general guidelines in mind and look at some specific instances of challenges to democracy that require some measure of reform.

→ Redefining democracy

  • We began this tour of democracy last year with a minimal definition of democracy.
  • We then looked at many cases and expanded the definition slightly to add some definitions:
    • The rulers elected by the people must take all the major decisions;
    • Elections must offer a choice and fair opportunity to the people to change the current rulers;
    • This choice and opportunity should be available to all the people on an equal basis; and
    • The exercise of this choice must lead to a government limited by basic rules of the Constitution and citizens’ right.
  • You may have felt disappointed that the definition did not refer to any high ideals that we associate with democracy.
  • You may have noticed that in the course of our discussions of various aspects of democratic government and politics, we have gone beyond that definition:
  • We discussed democratic rights at length and noted that these rights are not limited to the rights to vote, stand in elections and form political organizations.
  • We have taken up power sharing as the spirit of democracy and discussed how power sharing between governments and social groups is necessary for a democracy.
  • We saw how democracy cannot be the brute rule of the majority and how a respect for minority voice is necessary for democracy.
  • Our discussion of democracy has gone beyond tfie government and its activities.
  • Finally, we have had some discussion about some outcomes that one can expect from democracy.
  • In doing so, we have not gone against the definition of democracy offered last year. We began then with a definition of what is the minimum a country must have to be called a democracy.

JAC Class 10 Social Science Notes