Plant and Animal Nutrition

Nutrition in Plants
- Plants are autotrophs, meaning they can synthesize their own food.
- Photosynthesis is the process by which green plants make their own food using carbon dioxide and water in the presence of sunlight and chlorophyll.
- Chlorophyll is a green pigment present in the leaves that absorbs sunlight.
- Stomata are tiny pores on the surface of leaves through which carbon dioxide enters.
- Heterotrophs are organisms that cannot make their own food and depend on other organisms for nutrition.
- Parasites are organisms that derive nutrition from other living organisms (hosts).
- Saprotrophs are organisms that obtain nutrition from dead and decaying organic matter.
- Nutrients are essential components of food necessary for an organism's growth, development, and survival.
Nutrition in Animals
- Animals are heterotrophs and depend on plants or other animals for food.
- The process of taking food into the body is called ingestion.
- Digestion is the breakdown of complex food substances into simpler, soluble forms.
- Absorption is the process by which digested food is taken up by the blood vessels.
- Assimilation is the utilization of absorbed food for energy, growth, and repair.
- Egestion is the removal of undigested food from the body.
- Ruminants are animals that can digest cellulose due to the presence of bacteria in their rumen. Examples include cows, buffaloes, and deer.
- The human digestive system consists of the mouth, oesophagus, stomach, small intestine, large intestine, rectum, and anus.
- The liver secretes bile juice, which helps in the digestion of fats.
- The pancreas secretes pancreatic juice, which contains enzymes that digest carbohydrates, fats, and proteins.
- The small intestine is the site where the complete digestion of food takes place.
- Villi are finger-like projections in the small intestine that increase the surface area for absorption of digested food.
- The large intestine absorbs water and some salts from the undigested food.
Fibre to Fabric
- Fibres are thin strands that are used to make yarn, which is then woven or knitted into fabrics.
- Natural fibres are obtained from plants or animals (e.g., cotton, wool, silk).
- Synthetic fibres are man-made fibres produced from chemical substances (e.g., nylon, polyester).
- Wool is obtained from the fleece of sheep or goats.
- Silk is obtained from the cocoons of silkworms.
- Shearing is the process of removing fleece from the body of the sheep.
- Sericulture is the rearing of silkworms for the production of silk.
- Sorting is the process of separating fibres of different qualities.
- Scouring is the process of cleaning sheared skin to remove grease, dust, and dirt.
Heat
- Heat is a form of energy that makes things feel hot.
- Temperature is the measure of the degree of hotness or coldness of an object.
- Thermometer is an instrument used to measure temperature.
- Clinical thermometer is used to measure human body temperature.
- Laboratory thermometer is used to measure the temperature of other objects.
- The normal human body temperature is about 37°C.
- Heat flows from a hotter object to a colder object.
- Conduction is the transfer of heat through a substance without the movement of the particles.
- Convection is the transfer of heat by the movement of heated particles (occurs in liquids and gases).
- Radiation is the transfer of heat without any medium (e.g., heat from the sun).
- Conductors are materials that allow heat to pass through them easily (e.g., metals).
- Insulators are materials that do not allow heat to pass through them easily (e.g., wood, plastic).
- Sea breeze is the cool air that blows from the sea towards the land during the day.
- Land breeze is the cool air that blows from the land towards the sea during the night.
Acids, Bases and Salts
- Acids are substances that taste sour and turn blue litmus red.
- Bases are substances that taste bitter and turn red litmus blue.
- Neutral substances are neither acidic nor basic.
- Indicators are substances that change colour in acidic or basic solutions (e.g., litmus, turmeric, china rose petals).
- Litmus is a natural indicator extracted from lichens.
- Neutralization is the reaction between an acid and a base to form salt and water, with the evolution of heat.
- Salts are formed during neutralization reactions and can be acidic, basic, or neutral.
- Hydrochloric acid (HCl) is an example of a strong acid.
- Sodium hydroxide (NaOH) is an example of a strong base.
Physical and Chemical Changes
- Physical changes are changes in the physical properties of a substance (e.g., shape, size, state) without changing its chemical composition.
- Chemical changes are changes in which a new substance is formed, involving a chemical reaction.
- Rusting of iron is a chemical change.
- Crystallization is a physical process used to obtain pure substances from their solutions.
- Burning of a substance is a chemical change.
Weather, Climate and Adaptations of Animals to Climate
- Weather is the day-to-day condition of the atmosphere at a place with respect to temperature, humidity, rainfall, wind speed, etc.
- Climate is the average weather pattern taken over a long period of time (about 25 years).
- Polar regions have extremely cold climates, with animals adapted to survive in these conditions (e.g., polar bears, penguins).
- Tropical rainforests have hot and humid climates, with animals adapted to these conditions (e.g., monkeys, elephants).
- Adaptation is the process by which animals develop certain features that help them survive in their environment.
- Migration is the movement of animals from one place to another to avoid harsh climatic conditions.
Winds, Storms and Cyclones
- Wind is moving air.
- Air exerts pressure.
- High-speed winds and air pressure differences can cause cyclones.
- A cyclone is a weather system with a low-pressure area at the center and winds spiraling inward.
- The eye of the cyclone is a calm area at the center.
- Thunderstorms develop in hot, humid tropical areas.
- A tornado is a dark, funnel-shaped cloud that reaches from the sky to the ground.
- An anemometer measures wind speed.
Soil
- Soil is the uppermost layer of Earth's crust, which supports plant life.
- Soil profile is the vertical section through different layers of the soil.
- Soil horizons are the different layers of soil (A-horizon, B-horizon, C-horizon).
- Soil is formed by weathering of rocks.
- Soil types include sandy soil, clayey soil, and loamy soil.
- Sandy soil is well-aerated and drains water quickly.
- Clayey soil retains water and is less aerated.
- Loamy soil is a mixture of sand, clay, and humus, and is best for plant growth.
- Soil erosion is the removal of topsoil by wind, water, or human activities.
- Soil conservation is the prevention of soil erosion and maintaining soil fertility.
Respiration in Organisms
- Respiration is the process of breaking down food to release energy.
- Aerobic respiration occurs in the presence of oxygen.
- Anaerobic respiration occurs in the absence of oxygen.
- Breathing is part of respiration and involves inhaling oxygen and exhaling carbon dioxide.
- Humans breathe through their nose and lungs.
- The diaphragm is a muscular sheet that helps in breathing.
- Earthworms breathe through their skin.
- Fish breathe through gills.
- Plants respire through stomata in their leaves and lenticels in their stems.
Transportation in Animals and Plants
- Transportation is the process of carrying substances (e.g., nutrients, water, waste) to different parts of the body.
- Blood is a fluid connective tissue that transports substances in animals.
- Blood consists of plasma, red blood cells (RBCs), white blood cells (WBCs), and platelets.
- RBCs carry oxygen, WBCs fight infection, and platelets help in blood clotting.
- Blood vessels include arteries, veins, and capillaries.
- Arteries carry oxygen-rich blood away from the heart.
- Veins carry carbon dioxide-rich blood towards the heart.
- The heart is a muscular organ that pumps blood throughout the body.
- Excretion is the process of removing waste products from the body.
- Plants transport water and minerals from the soil through xylem.
- Phloem transports food from the leaves to other parts of the plant.
- Transpiration is the process by which plants lose water through their leaves.
Reproduction in Plants
- Reproduction is the process by which living organisms produce new individuals of the same kind.
- Asexual reproduction is a mode of reproduction that does not involve the fusion of gametes (e.g., budding, fragmentation, spore formation, vegetative propagation).
- Sexual reproduction involves the fusion of male and female gametes.
- Flowers are the reproductive parts of a plant.
- Pollination is the transfer of pollen grains from the anther to the stigma.
- Fertilization is the fusion of the male and female gametes to form a zygote.
- Fruits develop from the ovary after fertilization.
- Seeds develop from the ovules after fertilization.
- Seed dispersal is the process by which seeds are scattered away from the parent plant (by wind, water, animals, or explosion).
Motion and Time
- Motion is the change in the position of an object with respect to time.
- Speed is the distance traveled by an object per unit time.
- Speed = Distance / Time
- The basic unit of time is the second (s).
- The basic unit of distance is the meter (m).
- A simple pendulum is used to measure time and consists of a small object suspended by a thread.
- The time period of a pendulum is the time taken to complete one oscillation.
- Distance-time graphs can be used to represent the motion of an object.
- Uniform motion is when an object covers equal distances in equal intervals of time.
- Non-uniform motion is when an object covers unequal distances in equal intervals of time.
Electric Current and its Effects
- An electric circuit is a closed path through which electric current can flow.
- Electric current is the flow of electric charge.
- Components of an electric circuit include a battery, switch, bulb, and connecting wires.
- A switch is used to open or close an electric circuit.
- When an electric current flows through a wire, it produces heat.
- Heating effect of electric current is used in electric heaters, electric irons, and electric bulbs.
- An electromagnet is a temporary magnet made by passing electric current through a coil of wire wrapped around an iron core.
- An electric bell works on the principle of electromagnetism.
- Miniature Circuit Breakers (MCBs) are used to automatically switch off the electricity supply in case of overload or short circuit.
Light
- Light is a form of energy that enables us to see objects.
- Light travels in a straight line.
- Reflection is the bouncing back of light from a surface.
- Laws of reflection state that the angle of incidence is equal to the angle of reflection, and the incident ray, the reflected ray, and the normal to the reflecting surface at the point of incidence all lie in the same plane.
- A plane mirror forms a virtual, erect, and same-sized image.
- A spherical mirror is a curved mirror with a reflecting surface that is either convex or concave.
- A concave mirror converges light rays.
- A convex mirror diverges light rays.
- A lens is a transparent object with at least one curved surface.
- Convex lenses converge light rays and can form real and virtual images.
- Concave lenses diverge light rays and form virtual images.
- White light is composed of seven colors (VIBGYOR).
- Dispersion is the splitting of white light into its constituent colors.
Water: A Precious Resource
- Water is essential for all living organisms.
- Water exists in three forms: solid (ice), liquid (water), and gas (water vapor).
- The water cycle is the continuous circulation of water in nature, involving evaporation, condensation, and precipitation.
- Groundwater is water that is stored underground in aquifers.
- Water scarcity is the lack of sufficient water resources to meet water demand.
- Water pollution is the contamination of water bodies with harmful substances.
- Water conservation is the practice of using water efficiently to reduce unnecessary water usage.
- Rainwater harvesting is a method of collecting and storing rainwater for later use.
- Drip irrigation is a technique of watering plants by allowing water to drip slowly near the roots.
Forests: Our Lifeline
- Forests are important natural resources that provide various benefits.
- Forests help in maintaining the balance of oxygen and carbon dioxide in the atmosphere.
- Forests prevent soil erosion.
- Forests provide habitat for wildlife.
- Deforestation is the clearing of forests for other land uses.
- Afforestation is the planting of new trees to create forests.
- Sustainable forest management is the practice of managing forests to meet the needs of the present without compromising the ability of future generations to meet their own needs.
Wastewater Story
- Wastewater is water that has been used and contaminated by human activities.
- Sewage is wastewater containing human waste, household waste, and industrial waste.
- Sewage treatment is the process of removing pollutants from wastewater.
- Wastewater treatment involves physical, chemical, and biological processes.
- Septic tanks are used to treat wastewater in areas where there is no sewage system.
- Activated sludge is a biological treatment process that uses microorganisms to decompose organic matter in wastewater.
- Biogas is a mixture of gases produced by the anaerobic decomposition of organic matter.
- Sanitation is the provision of clean drinking water and proper disposal of sewage.