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Chapter 1: Matter in Our Surroundings

Characteristics of matter particles
There are spaces between matter particles
Matter particles move continuously – movement increases with rising temperature
Attract each other – decreasing order of force of attraction: solids > liquids > gases

Solid phase: Have permanent shape, size and boundary with negligible compressibility

Liquid phase: Have a fixed volume with low compressibility but no fixed shape

Gaseous state: Have high compressibility with no fixed shape, volume, and boundary

Boiling point: temperature at which the vapour pressure becomes equal to the atmospheric pressure. It can also be referred to as the temperature at which a liquid changes to its vapours.

Melting point → Temperature at which a solid melts into a liquid at normal atmospheric pressure.

Effect of change of pressure

If pressure is applied,

Melting point → decreases

Boiling point → increases

Latent heat → Heat required for breaking the force of attraction between the particles at transition temperature.

Amount of heat required to change 1 kg of material to change its state at normal atmospheric pressure at transition temperature is called the latent heat for that transition.

Dry ice → Solid carbon dioxide

Sublimation → Process of changing of a solid to its gaseous form

Evaporation → Change of liquid into vapours at any temperature below the boiling point. Takes the latent heat from body. Thus, the body cools when evaporation takes place.

Factors affecting evaporation
Surface area → If increases, rate of evaporation increases
Temperature → If increases, rate of evaporation increases
Humidity → If increases, rate of evaporation decreases
Wind speed → If increases, rate of evaporation increases
Chapter 2: Is Matter around Us Pure

Mixture – Contains more than one pure substance in any ratio/proportion

Substance – Cannot be separated into its constituent particles by any physical process

Solution – Homogeneous mixture of two or more substances

Alloys – Homogeneous mixture of metals

Properties of solution:
Homogeneous mixture
Particles are extremely small, not visible to the naked eye
Light path not visible
Solute particles cannot be separated by filtration

Concentration of solution = Solute amount / Solvent amount

Suspension – Heterogeneous mixture of solids and liquids where the solid particles suspend throughout the medium. Example: Mixture of chalk powder and water
Properties of suspension
⚬ Particles are visible to the naked eye
⚬ Light path visible
⚬ Particles settle down
Colloidal solution- Is a heterogeneous mixture, but appears to be homogeneous. Example: milk
• Properties of colloidal solution
⚬ Heterogeneous mixture
⚬ Particle size is small, not visible to the naked eye
⚬ Light path can be visible
⚬ Particles do not settle down
⚬ Substances cannot be separated by filtration

Tyndall effect → Scattering of light beam by suspended particles in the solution

Separation processes
• Evaporation – Used for separating mixture of volatile solvents and non-volatile solutes. Example: Separating salt from its solution
• Centrifugation – Used for separating components based upon the difference in their weights. Example: Separating mixtures of cream from milk
• Separating funnel – Used for separating two or more immiscible liquids. Example: Separating oil and water
• Sublimation process – Used to separate sublimable solids from their mixtures. Example: Separating ammonium chloride from a mixture
• Chromatography – Used to separate those solutes that dissolve in the same solvent. Example: Separating the components of a dye
• Distillation – Used to separate two miscible liquids that boil without decomposition. Example: Separating a mixture of acetone and water
• Fractional distillation – Used to separate a mixture of liquids when the boiling temperature difference is less than 25 K. Example: Separating different components of petroleum

Crystallization – Used to separate pure solids from a solution by forming crystal.
Example: Obtaining pure crystals of copper sulphate from an impure sample

Differences between a mixture and a compound
 Mixture Compound No new compound New compound Elements or compounds mix Elements react Properties of constituents remain unchanged New substance has totally new properties A constituent can be separated easily by physical methods Can be separated by chemical methods or electrolysis
Chapter 3: The Fundamental Unit of Life

Cell:  It is the smallest unit of life capable of performing all living functions.

On the basis of cell number, organisms are divided into two types:
Unicellular organism: made up of only a single cell, e.g. Amoeba, Paramecium
Multicellular organism:  made up of many cells, e.g. algae, plants, animals, etc.

Structural organization of cell
Cell wall: Outermost structure present in plant, fungal and some bacterial cells; absent in  animal cells
Plasma membrane or cell membrane: Outermost covering of all cells. It separates the contents of the cell from the external environment.

Important functions of cell membrane:
• Regulates the entry and exit of substances in and out from the cell
• Performs certain physical activities such as diffusion and osmosis
Diffusion: The spontaneous movement of molecules from a region of high concentration to a region of low concentration
Osmosis: The movement of water molecules from a region of high concentration to a region of low concentration, through a selectively permeable membrane

Cytoplasm: It is the fluid that fills the cell; It contains all cell organelles

Cell organelles
Nucleus: It controls all the cellular activities of the cell; acts like the brain of a cell.
Important components of nucleus:
Nuclear membrane
Nucleoplasm, containing chromatin
Nucleolus
Prokaryotic cell - The nuclear region is poorly defined; membrane-bound organelles are absent. The undefined nuclear region containing only nucleic acid is called nucleoid.
Eukaryotic cell – Nuclear region is bounded by nuclear membrane; membrane-bound organelles are present
Endoplasmic reticulum – It helps in the synthesis and packaging of proteins and lipids. SER plays a significant role in detoxifying many poisons and drugs. It is of two types;
SER - Smooth (due to absence of ribosomes) endoplasmic reticulum
RER - Rough (due to presence of ribosomes) endoplasmic reticulum
Ribosome: Site of protein synthesis
Golgi apparatus:  It is known as dictyosomes in plant cells
Helps in the storage, modification, and packaging of products in vesicles
Involved in the formation of lysosomes and peroxisomes
Lysosome: It contains digestive enzymes that can destroy any foreign material; also known as the ‘suicidal bag’ of a cell
Mitochondria - It is known as the ‘powerhouses of the cell’;
It is a double membrane bound organelle that have their own DNA; hence they are able to make some of their own proteins
Involved in cellular respiration
Produce energy in the form of ATP (Adenosine triphosphate). Hence, it is also known as energy currency of the cell.
Plastids: It is present only in plant cells. These are also double-membraned structures having their own DNA and ribosome. They are of two types;
Chromoplasts (coloured plastids): It include chloroplasts which are important for photosynthesis in plants
Leucoplasts (white or colourless plastids): It help in the storage of carbohydrates (starch), fats, and proteins
Vacuole: It is found in both plant and animal cells. It is single and large in plant cells while it is small and numerous in animal cells.
Important functions of vacoules:
Provide turgidity and rigidity to plant cells
Store some useful substances like amino acids, sugars, various organic acids etc.
In some organisms specialised vacuole performs the function of expelling waste material and excess of water.

Differences between plant and animal cells

 Animal cell Plant cell • Generally small in size • Cell wall is absent • Plastids are absent • Vacuoles are present in abundance and smaller in size • Usually larger than animal cells • Cell wall is present • Plastids are present • Vacuoles are usually single and larger in size

Milestones in Cell Biology
 Biologists Major contributions • Robert Hooke Discovered cell • Leeuwenhoek Discovered microscope • Robert Brown Nucleus • Purkinje Coined term protoplasm • Schleiden and Schwann Presented Cell theory • Camillo Golgi First described Golgi apparatus

Cell theory
• All plants and animals are composed of cells
• The cell is the basic unit of life.
• All cells arise from pre-existing cells.
Chapter 4: Tissues

Tissues: Group of cells that work together to perform a particular function

Plant tissues
On the basis of the dividing capacity, plant tissues are of two types: Meristematic and permanent tissue.
Meristematic tissues: It consists of actively-dividing cells. They are of three types;
Apical meristem: Present at the growing tips of stems and roots. Its function is to increase the length of stems and roots
Intercalary meristem: Present at the base of leaves or internodes. Required for the longitudinal growth of plants
Lateral meristem: Present on the lateral sides of the stems and roots. Its function is to increase the thickness of stems and roots.
Permanent tissues: Formed from meristematic tissues. The cell loses the ability to divide. Divided into two types
Simple permanent: Consist of only one type of cells. There are three types;
Parenchyma: Composed of unspecialised loosely packed living cells with relatively thin cell walls.
Parenchyma that contains chloroplast and performs photosynthesis is called chlorenchyma.
Parenchyma that contains large air cavities is called aerenchyma. These large air cavities provide buoyancy to aquatic plants.
Collenchyma - Composed of living and elongated cells with cell walls irregularly thickened at the corners; have very little intercellular spaces; provide flexibility and mechanical support to the various parts of the cells.
Sclerenchyma - Composed of long, narrow, and lignin deposited thick-walled cells. This tissue is made up of dead cells and there are no intercellular spaces. For example, husk of coconut.
Protective tissues: Protects the plant from external injuries. The two types of protective tissues are epidermis and cork
Complex permanent - Made up of more than one type of cell. These tissues constitute vascular bundles. They are of two types;
Xylem
Conducts water and minerals from the roots to the different parts of the plant
Composed of four different types of cells; tracheids, vessels, xylem parenchyma, and xylem fibres. Except xylem parenchyma all other xylem elements are non- living.
Phloem
Conducts food material from the leaves to the different parts of the plant
Composed of four different types of cells; sieve tubes, companion cells, phloem parenchyma, and phloem fibres. Except for phloem fibres, all other phloem cells are living.

Animal tissues
Animal tissues are classified into four types based on the functions they perform: Epithelial, Connective, Muscular and Nervous tissue.
Epithelial tissues: Tightly packed cells with almost no intercellular spaces. It forms the covering of the external surfaces, internal cavities, and organs of the animal body. They are of four types;
Squamous epithelium: Single layer of extremely thin and flat cells are called simple squamous epithelium while multi layered cells forms stratified squamous epithelium.
Simple squamous epithelium: Lining of the mouth, oesophagus, lung alveoli, etc.
Stratified squamous epithelium: Skin

Cuboidal epithelium: Consists of cube-like cells. Found in the lining of kidney tubules and ducts of the salivary glands
Columnar epithelium: Consists of elongated or column-like cells. Found in the inner lining of the intestine and gut
Glandular epithelium: Consists of multicellular glands
Connective tissues: Specialised to connect various body organs. Various types of connective tissues are:
Areolar tissue: Found in the skin and muscles, around the blood vessels, nerves, etc.
Adipose tissue: Acts as the storage site of fats; found between the internal organs and below the skin; acts as an insulator for the body
Dense regular connective tissue: Main components are tendons and ligaments.
Ligaments: Connective tissues which connects a bone to a bone. It is very elastic
Tendons: Connective tissue which connects a bone to a muscle. It has limited flexibility
Skeletal tissue: The main component of skeletal tissues are cartilage and bone
Fluid tissue: Blood is the vascular tissue present in animals. It is composed of plasma, Red blood cells (RBC), White blood cell (WBC) and platelets.
Muscular tissues: The main function of muscular tissue is to provide movement to the body. It is of three types
Striated muscles or skeletal muscles or voluntary muscles: Cells are cylindrical, un-branched, and multinucleate. Found in our limbs.
Smooth muscles or involuntary muscles: Cells are long, spindle-shaped, and possess a single nucleus. Found in oesophagus, iris of the eyes, in ureters.
Cardiac muscles or involuntary muscles: Cells are cylindrical, branched, and uninucleate. Found in the heart.
Nervous tissues: Highly specialised tissues present in the brain, spinal cord, and nerves.
Neuron: It is the functional unit of nervous tissue.
Chapter 5: Motion
Uniform motion – No change in velocity (No change in speed and direction)
Non-uniform motion – Change in velocity with time

Distance-time graph

Velocity-time graph

Equation of motion
• 1st equation: v = u + at
• 2nd equation: $s=ut+\frac{1}{2}a{t}^{2}$
• 3rd equation: 2as = v2u2

The motion of an object moving in a circular path is called circular motion.
Chapter 1: Atoms and Molecules

Law of conservation of mass: Mass can neither be created nor can it be destroyed in a chemical reaction.

Law of constant proportion: A chemical substance always contains the same elements in a fixed proportion by mass, irrespective of the source of compound.

Atom: The smallest particle which is the building block of matter.

The symbol of the element is made from one or two letters of the English or the Latin name of the element.

Atomic mass: The sum of the protons and neutrons in an element gives its atomic mass. The atomic mass of an atom of an element is also known as its relative atomic mass, since it is determined relative to the mass of C-12 isotope.

Molecule: It is formed when two or more atoms of the same element or different elements get combined chemically.

Atomicity: The number of atoms that combine to form a molecule is called the atomicity of the molecule.

Ion: A charged species in which an atom or a group of atoms possess a net electric charge (positive or negative).

• Cations → Positively charged ion

• Anion → Negatively charged ion

Chemical formula:  Representation of the composition of a molecule in terms of the symbols of elements present in that molecule.

Molecular mass: It is the sum of the atomic masses of all the atoms present in a molecule of that substance.

Formula unit mass: It is the sum of the atomic masses of all the atoms present in a formula unit of that substance.

Mole:  The mole is a unit of measurement for the amount of substance. One mole of a substance is the quantity of the substance containing 6.022 × 1023 numbers of particles (atoms, molecules, or ions).Chapter 6: Force and laws of motion
Inertia – Tendency of a body to resist any attempt to change its state of motion.
• Mass is the measure of inertia, higher is mass, higher is inertia.
• Momentum = mass × velocity = mv [kg m/s]

First law of motion
A body at rest remains at rest and a body in uniform motion continue its uniform motion unless an external force is applied.

Second law of motion
• Rate of change of momentum Applied unbalanced force
• Direction of change in momentum is the same as the direction of unbalanced force
o Numerically,

o Newton = Unit of force, 1 N = 1 kg × 1 m/s2

Third law of motion
For every action force there is an equal and opposite reaction force.

Conservation of momentum
For a system, momentum remains constant unless an external force acts on it.
${m}_{A}{u}_{A}+{m}_{B}{u}_{B}={m}_{A}{v}_{A}+{m}_{B}{v}_{B}$
Chapter 7: Gravitation

Kepler’s law of planetary motion
• First law: Orbits of planets are elliptical.
• Second law: Planet covers equal area in equal time intervals
• Third law:

Universal law of Gravitation
$F=G\frac{Mm}{{r}^{2}}$
• G = Universal gravitational constant = 6.673 × 10–11 Nm2 kg–2
• Inverse square law: $F\propto \frac{1}{{r}^{2}}$

Gravitation is a weak force unless large bodies are involved.

Force of gravitation due to the Earth is called gravity.
• Force of gravity decreases with altitude above surface of Earth.
• Force of gravity decreases with depth below surface of Earth.
• It also varies on surface of Earth, it decreases from poles to equator.

Force of gravitation explains – motions of moon and planetary tides

The motion of a body in which gravity is the only or dominant force acting upon it is called free fall.

Value of acceleration due to gravity during free fall is, g =9.8 m/s2, it is independent of mass of the falling object.

Weight of a body = Earth’s gravitational pull on the body

Weight on moon $=\frac{1}{6}$ weight on Earth

Tips to solve numerical
• For upward motion take g = 9.8m/s2 and final velocity at the highest point as 0.
• For downward motion take g = 9.8m/s2 and for a freely falling body take initial velocity as 0.

Thrust – Force acting perpendicular to a surface

Pressure = Perpendicular force per unit area

Buoyant force = Up thrust by a fluid on a body immersed in it [Depends on fluid density]
• If density of body > density of fluid, then the body will sink in the fluid, and vice versa
• (Density of cork) < (density of water), so cork floats
• (Density of iron) > (Density water), so iron sinks

Archimedes’ principle:
• Upward force experienced by a body immersed in fluid = Weight of the displaced fluid

Lactometer is a device to measure purity of milk.

Relative density Chapter 2: Structure of the Atom

❖ Atoms are not indivisible and are composed of three fundamental particles. These particles are electrons, protons, and neutrons.

Electrons: These are the negatively charged particle and were discovered by J. J. Thomson, by cathode ray experiment.

❖ Canal rays are positively charged radiations consisting of protons.

Protons: These are the positively-charged particles and were discovered by E. Goldstein.

Neutron: These are electrically-neutral particle and were discovered by J. Chadwick.

Various atomic models:
• Thomson's atomic model:Thomson thought that an atom is a sphere of positive charge in which electrons are embedded. An atom as a whole is electrically neutral because the negative and positive charges are equal in magnitude.
• Rutherford's atomic model: All the positive charges (i.e., protons) were present at the centre of the atom, inside the nucleus, and the electrons were present in circular orbits around the nucleus. The electrons are not at rest and keep moving continuously in these circular orbits. The size of the nucleus is very small as compared to that of the atom.
• Bohr’s atomic model: The electrons present around the nucleus revolve in specific orbits called energy levels. He also stated that the electrons do not release energy while revolving. The shells in which the electrons are present are known as K, L, M, N, and so on (or 1, 2, 3, 4, and so on), as proposed by Bohr and Bury. Each shell contains a specific number of electrons, which can be calculated using the formula 2n2.
 Atomic Models
Valency: It is defined as the combining capacity of the atom of an element. It depends upon the number of electrons present in the outermost shell of its atom.

❖ Atomic number of an element is equal to the number of protons present in the atom and atomic mass is equal to the sum of the number of protons and neutrons present in it.

Isotopes: These are the atoms having the same atomic number and different atomic masses.

Isobars: These are the atoms having the same atomic mass and different atomic numbers.Chapter 8: Improvement in Food Resources

Improvement in crop yields
• The crops grown in rainy season are known as kharif crops. These are grown from the month of June to October.
• Soya bean, paddy, maize, cotton, pigeon pea, green gram, and black gram are kharif crops.
• The crops grown in winter are known as rabi crops. The rabi season is from November to April.
• Wheat, gram, mustard, linseed, and pea are rabi crops.
• The variety of the crop can be improved by hybridization and genetic engineering.
• Hybridization is the crossing between genetically dissimilar plants. It can be intervarietal or interspecific.
• Genetic engineering is the deliberate insertion or deletion of genes in an organism for obtaining a better organism.
• The net crop yield can also be increased by adopting better cropping pattern(s) such as inter-cropping, mixed cropping, and crop rotation.
• Mixed cropping is growing two or more crops simultaneously on the same piece of land
• Inter cropping is growing two or more crops simultaneously on the same field in a different pattern.
• The growing of different crops on a piece of land in a pre planned succession is called crop rotation.

Factors for high variety improvement
• Improved quality
• Biotic and abiotic resistance
• Change in maturity duration
• Desired agronomic characteristics

Nutrient management
• There are 16 nutrient which are essential for plants
• Carbon, hydrogen and oxygen are called the framework elements
• The nutrients required in relatively large quantity for growth and development of plants are called macro nutrients. These are nitrogen, phosphorous, potassium, calcium, magnesium, and sulphur
• The nutrients required in low quantity are called micro nutrients. These are iron, manganese, boron, zinc, copper, molybdenum, and chlorine.
Manure
Manure is prepared by the decomposition of animal excreta and plant waste.
Manure is known to have a large quantity of organic materials and little amount of plant nutrients.
Manure helps in enriching the soil with organic matter and nutrients.
Cow dung, animal refuse, domestic wastes, etc., is decomposed to form manure.
Fertilizers
Fertilisers are commercially-available plant nutrients.
They can be organic or inorganic in nature. They ensure the healthy growth and development of plants by providing nitrogen, phosphorus, potassium, etc.
Urea, Potash, Ammonium nitrate etc are some examples of fertilisers.
Composting
Composting is a process in which farm waste materials such as livestock excreta (e.g., cow dung), vegetable wastes, domestic wastes, and sewage wastes are decomposed in pits to release the organic matter and nutrients.
When composting is done using earthworms to hasten the process of decomposition, it is called vermicomposting.

Crop protection
• Use of pesticides is the most common method of eradicating weeds, pests, and infectious diseases.
• Pesticides are commercially available as herbicides, fungicides, insecticides, etc.
• Excessive use of these chemicals can cause health hazards and environmental problems.
Animal husbandry
• Animal husbandry deals with the scientific management of livestock. These include cattle farming, poultry farming, fish culture, and bee culture.
• Cattle farming is done to obtain milk and draught labour for agricultural purposes.
• Poultry farming is undertaken to obtain egg production and meat.
• Fish is a cheap source of animal protein for our food. Therefore, fish culture is an important part of animal husbandry.
• In composite fish culture both local and imported fish species are used to increase the fish yield.
Aquaculture involves the production of aquatic animals that are of high economic value such as prawns, fishes, lobsters, crabs, shrimps, mussels, oysters, etc.
• The practice of bee keeping is known as apiculture. Bee farms are also known as apiaries.
• Local varieties of bees used commonly for honey production are Apis cerana, Apis dorsata, A. florae.
• An Italian bee variety A. mellifera is used for commercial production of honey
Chapter 3: Diversity in Living Organisms

❖ Diversity: It refers to the variety and variability among living organisms from all sources including land, water, and other ecosystems.

❖ Classification: It refers to the identification, naming, and grouping of organisms into a formal system based on similarities in internal and external structures or evolutionary history

❖ Characteristic: A feature that helps identify or describe a person or a thing.

❖ Principles of classification
• Nature of cell (Fundamental characteristic): prokaryotes and eukaryotes
• Cellularity: unicellular and multicellular
• Mode of nutrition: autotrophs and heterotrophs

Classification and evolution
• Primitive organism or lower organism has a simple body structure and ancient body design
• Advanced organism or higher organism has a complex body structure and organisation
• Evolution: The process of gradual and continuous change in primitive or simple organisms to give rise to advanced organisms
• Biodiversity: The variety of life forms present in various ecosystems

Hierarchy of classification: Kingdom Phylum (for animals)/ Division (for plants)  Class  Order  Family  Genus  Species.
Mnemonic to learn this hierarchy: Kids Prefer Cheese Over Fried Green Spinach
• Species is the basic unit of classification
• Carolus Linnaeus developed the hierarchy of classification. Linnaeus also developed the concept of binomial nomenclature
• Binomial nomenclature In this system, the name of a species is made up of two words: the genus name and the species name. E.g. Rosa indica
R.H. Whittaker (in 1969) proposed a five-kingdom classification of living organisms
The five kingdoms proposed by Whittaker along with their features are

 Kingdom Special feature Example of organisms Kingdom Monera Prokaryotic and unicellular organisms. bacteria, blue-green algae, or cyanobacteria Kingdom Protista Unicellular, eukaryotic organism Amoeba, Paramecium, diatoms etc Kingdom Fungi Multicellular eukaryotic heterotrophic (saprophytic) organisms with citinious cell wall Yeast, mushroom, Penicillium, Aspergillus, etc Kingdom Plantae Multicellular eukaryotic autotrophic organisms with cellulosic cell wall All plants Kingdom Animalia Multicellular eukaryotic heterotrophic organisms with no cell wall All animals

Kingdom Plantae: It includes five divisions:
• Division Thallophyta: Includes Spirogyra, Cladophora, Ulva
Plant body is not differentiated into true root, stem, and leaves
• Division Bryophyta (also called amphibians of plant kingdom):
⚬ Includes mosses, Riccia, Marchantia,
Specialised vascular tissues (such as xylem) for the conduction of water are absent
⚬ Body is differentiated into stem and leaf like structures

⚬ Naked embryo i.e. spores are present.
Division Pteridophyta:
⚬ Includes ferns, Marsilea, Equisetum
⚬ Specialised vascular tissues for the conduction of water are absent
⚬ Naked embryo i.e. spores are present

Cryptogams: Plants that do not have well differentiated reproductive organs and produce naked embryo (spores) are called cryptogams. Thallophyta, Bryophyta and Pteridophyta all possess naked embry

❖ Phanerogams: Plants that have well developed reproductive organs that finally make seeds are called Phanerogams. Gymnosperms and angiosperms belong to Phanerogams.
Division Gymnospermae:
⚬ Includes Pinus, cedar, fir, Juniper, Cycas, etc:
⚬ Seed bearing, non-flowering plants
⚬ Bear naked seeds, not enclosed inside fruits.
• Division Angiospermae: Includes all flowering plants:
Flowering plants in which seeds are enclosed inside fruits.
Seeds develop inside the ovary, which develops into a fruit
Monocotyledons: Seeds that have one cotyledon. E.g. maize, wheat etc
Dicotyledons: Seeds that have two cotyledons. E.g.  Sunflower, gram etc

Kingdom Animalia
Kingdom Animalia can be divided into two major groups on the basis of the presence or absence of notochord: non-chordata and chordata
Non-chordata can be further divided into the following phyla:
• Phylum Porifera: Includes sponges such as Spongilla, Euplectella, etc:
⚬ Cellular level of organisation
Mainly found in marine habitats
⚬ Posses canal system for circulating water.
• Phylum Coelenterata: Includes sponges such as Spongilla, Euplectella, etc
⚬ Tissue level of organisation
⚬ Body cavity (coelom) is absent
⚬ Diploblastic i.e body is made of two layers of cells.
• Phylum Platyhelminthes: Includes flatworms, liver flukes and planarians
⚬ Bilateral symmetry
⚬ Triploblastic  i.e. three layers of cells are present
⚬ Body cavity is absent
• Phylum Nematoda (Aschelminthes): Includes roundworms - Ascaris
⚬ Bilaterally symmetrical
⚬ Triploblastic
⚬ Pseudocoelom (false coelom)  is present
• Phylum Annelida: Includes segmented worms such as earthworms and leeches
⚬ Bilaterally symmetrical
⚬ Triploblastic
⚬ Body is segmented
• Phylum Arthropoda: Includes crabs, prawns, insects, spiders, scorpions, etc
⚬ Largest group of the animal kingdom.
⚬ Bilaterally symmetrical and segmented
⚬ Coelomic cavity is blood-filled
⚬ Presence of Jointed legs
• Phylum Mollusca: Includes snails, octopus, Pila, etc
⚬ Bilaterally symmetrical, little segmentation
⚬ Coelomic cavity is reduced
⚬ Open circulatory system and kidney like organ for excretion is present.
• Phylum Echinodermata: Includes marine animals such as starfishes, sea urchins, etc
⚬ Spiny skinned organisms
⚬ Free living marine organisms
⚬ Triploblastic and coelomate
⚬ Skeleton is made of calcium carbonate

Chordata can be further divided into sub-phyla Protochordata and Vertebrata
Protochordata: Includes Herdmania and Amphioxus
⚬ Triploblastic, and have a coelom cavity
⚬ Bilaterally symmetrical
⚬ Notochord at some stages of life is present.
⚬ Notochord is a flexible rod like structure that forms the supporting axis of the body in the chordates.
• Vertebrata: The sub-phylum Vertebrata is further divided into five classes:
• Class Pisces: Includes all fishes
⚬ Exclusively aquatic animals
⚬ Body is streamlined and covered with scales
⚬ They are cold blooded animals
⚬ Heart is two chambered
⚬ Skeleton is bony or cartilaginous
⚬ Oviparous. They lay eggs in water.
• Class Amphibia: Includes frogs, toads, and salamanders
⚬ Scales are absent
⚬ Cold blooded animals
⚬ Heart is three chambered

⚬ Oviparous. They lay eggs in water
⚬ Have a dual mode of life (in water and land); respire through gills, skin and lungs
• Class Reptilia: Includes reptiles such as lizard, snake, turtle, etc
⚬ Cold blooded animals
⚬ Most of them have three chambered heart (Crocodiles have four chambered heart)
⚬ Skin is covered with scales
⚬ These animals are completely terrestrial. They breath through lungs
⚬ Lay eggs on land (oviparous)
• Class Aves: Includes all birds
⚬ Warm-blooded animals with four chambered heart
⚬ They breathe through lungs
⚬ Have feathers and forelimbs modified for flight
⚬ Exclusively egg-laying animals
• Class Mammalia: Includes kangaroo, rat, dolphin, elephant, horse, human, tiger, etc
⚬ Warm-blooded animals with four chambered heart
⚬ Most of them are viviparous except for platypus and echidna. They both are oviparous
⚬ These animals have milk-producing glands (mammary glands) to nourish their young ones
Chapter 4:  Work and Energy

❖ Scientifically, work is done when:
• There is a displacement.
• Displacement is in any direction except the direction normal to the direction of force.

❖ No work is done when
• Net displacement is zero. [No work is done in circular path]
• Displacement occurs perpendicularly to the applied force

❖ Work = Force × Displacement [along force direction]
W = F × s  [Unit – Joule, 1 J = 1 N.m]

❖ Unit of energy: Joule

❖ Commercial unit of Energy: kWh

❖ The energy possessed by a body by virtue of its motion is called kinetic energy.

❖ Kinetic energy of a body , where m is mass and v is speed of the body.

❖ Proof:

❖ Energy possessed by a body by virtue of its position or its shape is called potential energy.

❖ Gravitational potential energy = mgh where, m is mass, g acceleration due to gravity, and h is the height above surface of Earth.

Law of conservation of energy: Energy can neither be created nor destroyed, it is only converted from one form to other.
Total energy is constant:

❖ Power is the rate of work done.Chapter 5:  Sound

❖ Sound is a mechanical wave and requires a medium to propagate.
• It cannot pass through vacuum.

❖Sound waves are longitudinal waves and propagate by continuous compressions and rarefactions of the medium.

Longitudinal wave:
Individual particles of the medium move in the direction parallel to the direction of wave propagation

Transverse wave:
Particle movement is perpendicular to the wave propagation

❖ Characteristics of sound waves

❖ AmplitudeMagnitude of maximum displacement from mean position

❖ Wavelength (λ) – Distance between two consecutive compressions or two consecutive rarefactions.

❖ Frequency – Number of oscillations per unit time (Unit - Hertz, Hz)

❖ Time period – Time taken by two consecutive compressions or rarefactions to cross a fixed point

❖ Pitch – Higher the frequency, higher the pitch

❖ Loudness – Determined by amplitude

❖ Tone – Sound of single frequency

❖ Speed of sound depends on temperature, pressure, humidity and nature of the material medium.
• Speed increases with increasing temp.

❖ Speed in solid > Speed in liquid > Speed in gas
• In air, speed 344 m s–1 at 22 °C
• Supersonic – More speed than sound
• Sonic boom - loud noise produced by supersonic object is sonic boom

❖ Echo- Reflection of  sound
• Sensation of sound persists   in the human brain
• Minimum distance to hear echo =

❖ Reverberation Persistence of sound by repeated reflection
• Uses – Loud speaker, stethoscope, curved ceiling of a concert hall, sound board in a big hall

❖ Range of hearing for humans: 20 – 20000 Hz
• But, rhinoceroses use infrasound

Application of ultrasound : Cleaning, detecting defects in metals, echocardiography, ultrasonography, to break small kidney stone

❖ SONAR is Sound navigation and Ranging.

❖ Human ear: Pinna collects sound; eardrum vibrates in response to sound
• Vibrations are amplified by the three ear bones [hammer, anvil, stirrup (smallest human bone)]
Chapter 6: Why Do We Fall Ill

❖ Health: A state of physical, mental, and social well-being, which includes a unity and harmony within the mind, body, and soul of an organism

❖ Disease: Any condition that can lead to discomfort, distress, health problems, and even death of the affected person

❖ Symptoms: Indications of disease, such as headache, stomach pain, nausea, etc that can only be felt by the patient

❖ Signs of a disease include fever, vomiting, diarrhoea, etc that can be observed by a physician

❖ Incubation period: The time interval between infection and appearance of symptoms

❖ Causes of disease
• On the basis of its duration - Acute and Chronic
Acute:  Lasts for a short period of time, E.g. Cold, cough, influenza, etc.
Chronic: Lasts for long periods of time, E.g. Diabetes, kidney stones, etc.
• On the basis of causative agents - Infectious and Non-infectious
Infectious: Diseases such as influenza, cold, etc., which are caused due to infectious agents
Non-infectious; Diseases such as high blood pressure, cancer, etc., which are caused by some internal causes such as excessive weight, genetic defects, etc.

Infectious agents: disease-causing microorganisms which belong to different categories such as:
Viruses: These are tiny organisms that grow, multiply, or reproduce only inside the host cells. Diseases caused by viruses include Influenza, cold (Rhinovirus), dengue, AIDS, SARS etc.
Bacteria: These are unicellular organisms; larger than viruses. Diseases caused by bacteria include whooping cough, typhoid, cholera, anthrax, etc.
Fungi: These are plant-like organisms; heterotrophic. Diseases caused by Fungi include Athlete’s foot, candidiasis, ringworms, etc.
Protozoa: These are simple, primitive unicellular organisms which are often found in water. Diseases caused by Protozoa include amoebiasis, kala azar (Leishmania), malaria, African sleeping sickness (Trypanosoma), etc.
Multicellular animals like worms - These are parasites that infect the intestines of human beings and other animals. Diseases caused by worms include diarrhoea, liver rot, etc.

❖ Communicable diseases: An infectious disease is classified as communicable disease when it can be transferred from an infected person to a healthy person

❖ Means of disease spread
Air-borne diseases: Transmitted when disease-causing microorganisms are expelled into the air by coughing, sneezing, talking, etc. E.g. common cold, chicken pox, small pox, pneumonia, influenza, tuberculosis, etc.
Water-borne diseases: Spreads when the excretions (from an infected person) containing causal microorganisms get mixed with drinking water and this contaminated water is consumed. E.g. cholera, typhoid, hepatitis A, etc.
Physical contact: Includes sexually-transmitted diseases. E.g. syphilis, gonorrhoea, AIDS, etc.
Blood to blood contact: Such contact is established during blood transfusion or pregnancy (between the mother and her baby). E.g. AIDS can spread through blood contact
Animals: Animals which transfer disease-causing microorganisms from an infected person to others are called vectors. E.g. female mosquitoes can transfer the malaria-causing Plasmodium

❖ Effects of diseases
Local effects: Includes swelling, pain, joint stiffness, etc., occur only at the site of infection
General effects: Includes fever chills, headaches, fatigue, loss of appetite, etc., occur all over the body
Inflammation: The process by which the body’s immune system shows response to protect the body from infection

❖ Prevention of diseases
Antigens: Foreign substances that invade our body
Immunisation: The protection of the body from communicable diseases by administration of some agent that mimics the microbe.
Vaccine: The suspension of killed microbes that mimics the disease causing microbes.
Vaccines are available against tetanus, polio, measles, hepatitis B, etc.
Chapter 7: Natural Resources

❖ Role of the atmosphere → Atmosphere acts as a heat protector and it plays an important role in the generation of wind.

❖ Soil: It is a mixture of small rock particles and decayed living organisms.

❖ Humus: A constituent of soil which makes it fertile

❖  Factors that influence soil formation:
Sun: Heats up the rock during the day
Rocks cool during night time
Formation of creaksbreaking of rocks
Water – water in cracks freeze  breaks rocks
Water carries rocks  friction breaks rocks
Wind – Particles in air erode the rocks

❖ Greenhouse effect: The trapping up of reflected solar radiations by the earth’s atmosphere and gradual heating up is known as greenhouse effect.

❖ Biogeochemical cycles
Water Cycle

Nitrogen cycle

Carbon cycle

Oxygen cycle
❖ Ozone layer: It is a very important layer of the atmosphere which absorbs the harmful ultraviolet rays. A hole in the ozone layer has been caused by CFCs which results from human activities.
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