Living Things – Living things are the organisms which possess life, usually identified with few characteristics such as growth, movement, reproduction etc. Examples: dogs, cats, housefly, humans, trees, shrubs etc.

Non-living things – Non-living things do not possess life, they do not have any of the characteristics of a living organism. Examples: Chairs, tables, pens, clouds, soil etc.

What are the characteristics which differentiate living organisms from nonliving things?

Living organisms possess certain characteristics like growth, movement-internally and externally, reproduction, excretion, respiration, sensitivity or response to stimuli and have a definite life span.  All the characteristics are shown by the living organisms throughout their life period.

Growth – Growth is the gradual development of age, size, height, weight etc. in living things. Example: A kitten grows into a cat, A child grows into an adult human being.

Germination – Germination is the process of growth of a young plant or seedling from the seed when the suitable conditions like temperature, water and air are available.

Locomotion – Locomotion is the ability to move from one place to another.

Excretion – Excretion is a process of eliminating waste products that are being produced inside the body. Example: Kidneys help in excreting the wastes in the from of urine

Egestion – Egestion is the process of removal of undigested food from the body.

Reproduction – Reproduction is the process of producing offspring/the young ones that are similar to the parent organism.

Respiration – Respiration is the process of producing energy from the food we consume with the help of oxygen.

Breathing – Breathing is the process of taking in air (inhalation) and giving out air (exhalation). It is a part of respiration.

Stimuli and stimulus – Stimuli are the changes or events in the surroundings that make an organism respond or react to them. Example: When we touch a hot pan we get the sensation of heat, and withdraw the hand. Here, heat is the stimulus and withdrawing the hand is the response. Stimulus is a singular term and stimuli is plural.

Nutrition – Nutrition is a method/ mode by which food is consumed by the organism and its utilization for nourishing the body (to provide energy, growth, development etc.)

Photosynthesis – Photosynthesis is a process by which plants produce their own food. Plants use carbon dioxide and water to prepare their food in the presence of sunlight.

Plants – A plant is a living organism that is capable of growing in land as well as water. It produces its own food by photosynthesis. It generally has roots, stem, leaves and flowers (some plants are non-flowering) Examples: Mango tree, Sunflower, Water lily, Money plant etc.

Animals – Animals are the living organisms that show locomotion and they depend on other organisms for their food. Examples: Cats, Birds, Fishes, Humans etc.

 Energy – Energy is the strength required to do any mental or physical activity. Organisms use the energy they get from food to grow, to reproduce, to respond to stimuli, to carry out daily activities etc.

Organism – An organism refers to an individual living thing that shows the characteristic features of life such as movement, reproduction, growth and development etc.

 Clouds also grow in size and move from one place to another. Then why are clouds nonliving?

In living organisms all the characteristics are shown at some or the other point of life though not all at once. But clouds only show two characteristics: growth (due to accumulation of water droplets) and movement from one place to another (with the help of wind) which is different from living organisms. They do not show the remaining characteristics like respiration, excretion and reproduction. Hence, clouds are non living things.

 Stomata –

• Stomata are the small openings (pores) that are present on the surface of the leaves.
• They are present more in number on the lower surface (under side) of the leaves. These small pores help in gaseous exchange and also help in transpiration. When stomata are open, air enters or leaves just like in the windows.

Transpiration – Transpiration is the loss of excess amounts of water in the form of water vapor from the surface of leaves with the help of tiny pores known as stomata. It helps the plant to absorb more water and minerals from the soil and also helps in keeping the plant cool during hot weather like how we sweat.

Earthworm – Earthworm is a type of worm that is found in the soil. It has bristles for movement. It is also known as the ‘Farmer’s friend’.

Lungs – Lungs are a pair of organs situated within the rib cage that are spongy and pink in color. They help in breathing.

Gills – Gills are a pair of organs found in aquatic animals such as fish, they are involved in the process of breathing under water.

Slimy – Slimy substances are the things that are wet and a little sticky.

Slimy skin – Some organisms naturally have a slimy substance on their skin which makes their skin wet and sticky. Example: Earthworms

Wastes in human body – Waste products that are being removed in human bodies are urea, salt, uric acid and other chemical substances which could be harmful.

Shedding of leaves – In unfavorable weather conditions some plants drop their leaves to reserve the food and protect themselves. This process of removing leaves is called, shedding of leaves. Plants also store waste materials in the old leaves, so that the wastes get removed when the leaves shed off.

Resin – Resin is a sticky substance which gets released or oozes out from some trees. It is insoluble in water and is used in making glues and varnishes.

Latex – Latex is a milky secretion oozes out from some plants when the plant is cut.  Latex of the rubber trees is the natural source of rubber.

Secretion – A process by which a cell or an organ of a living organism produces chemical substances that are required for various functions. For example- Mouth secretes saliva

Vegetative part of a plant – Except flowers, all other parts of the plant are known as vegetative parts. Flowers are known as reproductive parts as they help in reproduction in plants. Example: Root, Stem and leaf.

Sensitivity – Sensitivity is the ability of responding to the stimuli such as heat, pain, pressure etc. It can also be termed as the response to stimuli.

Mimosa pudica/Touch me not – Leaves of the touch-me-not plant (Mimosa pudica) curl up or get folded when touched due to sudden loss of water. Hence it got the name as touch-me-not. Touch is the stimulus and curling of the leaves is the response. The plant curls its leaves as a method of self-protection so that the animals do not eat them.

Internal Movement – Movement of substance inside the body of an organism is called internal movement. Example: Movement of blood inside our body.

External Movement – Movements that take place outside the body of an organism. Example: Waving hands, Walking etc.

Life span – A period of life of an organism from its birth to death is called life span. Examples: Lifespan of dogs – 10 to 13 years, Lifespan of horse – 25 to 30 years.

Polar bear – Polar bear is an animal that lives in polar regions. It has white fur, black skin and a thick layer of fat under their skin.

Cactus – Cactus is a desert plant which has modified stems and leaves. It also has long roots that penetrate deep into the soil for absorption of water.

Weather  – The day-to-day conditions of the atmosphere such as temperature, rainfall, wind etc. at a particular place is called weather.

Climate – A climate is the average weather of a particular place over years.

Habitat  – Habitat is a natural place where organisms live. It provides food, water, shelter and space to survive . It consists of both biotic and abiotic factors.

Biome – A biome is a large biological community where different types of plants and animals live, they share common characteristics specific to that area.

Nocturnal –Nocturnal animals are the animals that hunt in the night and stay in their burrow during the day time.

Shrubs – Shrubs are the type of plants that are bushy and branch into a few thick stems at base.  They are shorter than trees and larger than herbs.

Predator – Predators are the organisms that eat other animals. For example in case of a lion and deer, the lion is the predator that hunts the deer.

Prey – Preys are the animals that are being eaten by the predators.  For example in case of a lion and deer, the deer is the prey which gets hunted by the lion.

Hooves – Hoof (Plural is Hooves) is the horny part of the foot found in animals such as mountain goats, horses, deer. Hooves help the animal to walk long distances on the rocky mountain surfaces.

Ecosystem – An ecosystem is a community of living organisms (biotic factors) like plants and animals that interact with each other and their environment (abiotic factors).

Biotic – Bios means life. Biotic things or factors include all living organisms. Examples include cats, trees, dogs etc.

Abiotic  – Abiotic things or factors include all the non-living things. Examples include Table, pen, notebook etc

Streams – Stream is a flowing water body similar to a river but smaller and narrower in size.

Salinity – Salinity is the amount of salt dissolved in the water.

Saline water – If the water has a high concentration of dissolved salt in it, it is called saline water.

Terrestrial habitat – Terrestrial means land. Terrestrial habitats are ones that are found on land, like forests, grasslands and deserts.

Aquatic habitat – Aquatic refers to water. Aquatic habitat is a habitat with water bodies such as a river, lake, pond, sea and oceans.

Acclimatization – Small changes that take place in the body of an organism to get used to to changes in surroundings are called acclimatization. This takes place over short periods of time.

Adaptation – Adaptation is the specific features or the changes in behaviour and appearance that enable an organism to live in a particular environment (habitat), depending on the factors like temperature, availability of water etc. Adaptation takes place over thousands of years.

Blow holes – Nostrils of animals like whales and dolphins are called blow holes, they are involved in breathing and are located at the top or back of their head. Dolphins and whales do not have gills. They have lungs. They breathe air through their blowholes.

Adaptations in camel

• They have long legs to keep their body away from the hot sand.
• They excrete small amounts of urine and their dung is very dry.
• They have long eyelashes to protect their eyes in sandstorms.
• They are capable of losing very little water from their bodies and hence can survive without water for a long period of time.

Hump – Elevated fleshy structure on the back of a camel. Food is stored as fat in the hump. And hence the camel can go on without eating for months.

Adaptations in fish

• They have streamlined bodies to help them swim easier in water.
• Body is covered with slippery scales that protects them as well as assists them with easy movement under water.
• They have thin fins and a tail that helps in the change in direction and maintain balance during movement.
• Gills help in respiration.

Streamlined body – Streamlined body is the one which has pointed or narrow ends and the middle portion is wider. This streamlined shape of the body helps fish to swim easily without resistance from water and birds to easily fly without resistance from air.

Adaptations of desert plants

• The leaves in desert plants are either absent or are very small and form spines, to reduce loss of water through transpiration.
• Photosynthesis is usually carried out by stems.
• The stem is covered with a thick waxy layer which prevents the loss of water.
• Roots grow long and deep in search of water inside the ground.

Adaptations of high altitude plants. – The trees are cone shaped with sloping branches provided with needle-like leaves that helps water and snow to easily slide off.

Adaptations of aquatic plants

• Roots are highly reduced and their main function is to hold the plant in place.
• Only the flowers and leaves of some plants float on the surface of water to receive maximum sunlight.
• Submerged plants will have highly divided leaves that allow easy flow of water through them without damaging them.

Frog

• They are capable of living in both water as well as land. Adult frogs breathe through skin under water, and when on land they breathe through their lungs.
• They have strong legs that help them in leaping and webbed feet that help in swimming.

Why do we experience difficulty in breathing in higher altitudes and while doing physical exercises?

At higher altitudes like on mountains the availability of oxygen is less. So, we have to breathe more to supply the body with the amount of oxygen it requires. This causes difficulty in breathing.

Our body uses oxygen to breakdown food and release energy. When we do vigorous exercises, our body requires more energy. So more oxygen is required. So, to supply the body with the required amount of oxygen we breathe more. This causes difficulty in breathing.

Why do nocturnal animals like desert snakes, rats etc., come out only during the night?

Animals that are active during night are called nocturnal animals. Many desert animals are nocturnal to avoid the hot sun during the day time while the nights in deserts are cooler. They cannot get easily noticed in the night so they can easily escape from the predators. 

Why do desert plants have spines?

In desert plants, leaves are modified into spines like in cactus to prevent the loss of water through transpiration and also to protect themselves from getting eaten by the herbivore animals of the desert.

Why do frogs and ducks have webbed feet?

Frogs are amphibians which live both on land and water. Aquatic birds like ducks, swans, penguins etc., spend most of their time in water. So, to help these organisms to swim easily in water, they have webbed feet, which act as paddles (the flat blades used in boats to move forward in water) and help in moving them forward.

Melanin – A pigment which is responsible for giving color to the skin, hair and eyes. It also protects our skin from the sun.

Why are people dark skinned ?

People in high temperature regions are exposed more to the sun and hence they have more melanin – to protect their skin from the sun. That is why they are dark skinned.

Digestion in housefly – The housefly vomits digestive juices and saliva onto the food material and sucks in the partially digested food

Digestion in dogs – They have a short digestive system because they feed on meat that has been dead for sometime. They digest and excrete within 6 hours. They have a short digestive system / digestion duration because if the meat stays in the digestive system for any longer the meat starts decaying and that is harmful for the dog.

Digestion in Rabbits

• The undigested food is stored as moist pellets in the small intestine of the Rabbit. It is acted upon by digestive enzymes and it gets partially digested. The pellets are excreted as faeces
• And it is consumed again by the rabbit to complete digestion.

Genes – They determine our physical characteristics – how we look etc.

Melanoma / skin cancer – if skin is exposed to sun for a long time it changes its genetic structure which leads to cancer.

Sweating is an adaptation, how ?

Human body temperature is 37 degree Celsius. And we are adapted to maintain this temperature by sweating. When the surrounding temperature is high and we feel hot, we sweat. This sweat evaporates and cools the body down.

Ecology – Ecology is the study of living organisms and their interaction with each other and with the environment.

Kangaroo rat – A nocturnal desert animal. It never drinks water but breaks down fat in the body and the hydrogen molecule in fat combines with oxygen and forms tiny amounts of water.

 Spiny leaves – Cactus plants have long pointed spines (leaves are modified into spines) to reduce water loss due to transpiration.

 Grassland  – A biome which has large trees and carpets of grass.

 Tundra

• It is a biome which is covered with ice and it is the coldest and harshest biome.
• Plants in this region are short in height, to protect themselves from the wind. The leaves are leathery to store moisture and heat.

 Countershading  – In fishes, the upper body is dark colored and the lower body part is lightly colored. This happens so that the fish is camouflaged (blends with the colour) in the water and is protected from predators.