All about Air

All about Air Air supports life on earth

Air supports life on earth. Air helps in the scattering of seeds and pollens of plants. Animals use air for respiration. Plants use air to prepare their food. Air is present everywhere. Atmosphere is a thin layer of air surrounding the earth. The atmosphere is dense at the surface of the earth and becomes thinner as one moves up. Air is: Transparent Colourless Occupies space The movement of air is called breeze or wind depending on its velocity or speed. The following are the various components of air: Nitrogen Oxygen Carbon dioxide Water vapour Smoke and dust particles

Nitrogen Is the major component of air Does not support burning Oxygen: Is the second largest component present in air Supports burning Smoke and dust particles present in air are harmful for the body. Animals and humans breathe in oxygen and give out carbon dioxide during respiration. Plants taken in carbon dioxide present in the atmosphere to make food and release oxygen into the atmosphere.

Effects of Rainfall - Draughts and Floods

Effects of Rainfall - Draughts and Floods Water is used in our day to day life.

Uses of Water Water is used in our day to day life. Water is used for everyday needs such as brushing, bathing, washing, cleaning etc. Farmers use ground water to water their fields. Many industries use ground water to produce everything from paints and fabric to leather and chemicals. So ground water is used for many purposes. Moreover the decline in the number of trees, excess usage of water and the presence of concrete in the areas does not allow the rain water to seep into the ground which is the reason for the shortage of water. Droughts Due to lack of rains the wells, lakes, ponds get dried up and thereby creating water scarcity and as result droughts are possible. If there are no rains, then the soil becomes more dry and patchy. Droughts occur when there are no rains for a longer period of time. There is less rainfall because trees are cut down. Droughts results in drying up of the crops and vegetation and this effects the availability of food for villages and food for the other animals. Finally this leads to malnutrition in humans. Floods Due to heavy rainfall the water levels in ponds, lakes rises to a greater extend and the rise in the water level of these water bodies causes the excess water to spread across causing floods. Floods wash out the living beings such as fish and other animals etc. and they create great havoc to the mankind. Once the rains stops the flood water receded, fish, cattle and other animals were left dead.     Floods cause lot of harm to the living beings and there will be loss in property also.

Rain Harvesting Harvesting is a method to collect rain water and store the rain water. The purpose of harvesting rain water is that two thirds of the earth is covered with water. Ocean and sea water contains many dissolved salts and cannot be used for drinking, agriculture and domestic purposes. So constant use of ground water results in scarcity of groundwater. So rain harvesting clears the problem of depleting the ground water. Technique involved in rain harvesting First collect the rain water at the rooftop and then allow the rain water to travels through the pipes or drains and then attach a wire mesh to the mouth pipe which filters large fragments such as leaves etc. This water is transported to the water tanks. These tanks contain layers of sand, gravel, charcoal that will filter the dirt and other impurities from rain water. The water stored in the tank will then be transported to an underground pit which will help water to seep back into the ground. Rain harvesting solves the problem of depleting the ground water and droughts.

Water Cycle

Water Cycle HOur Earth is covered by two-thirds of water, but most of the water is not portable and contains salt

Our Earth is covered by two-thirds of water, but most of the water is not potable and contains salt. Water is used for various activities such as agriculture, industries, cooking, cleaning utensils, bathing, washing clothes, and, most importantly, for drinking. Ponds, wells, streams, lakes and rivers are the different sources of drinking water.They are supplied water by the oceans and seas.Oceans and seas supply water to other water bodies through the water cycle. The circulation of water from the oceans and the surface of the earth, to the air as water vapour, and its return to the ocean as rain, hail or snow, is called the water cycle A variety of salts, like sodium chloride, calcium, magnesium and potassium, are present in saline water. The evaporation of water takes place in the water cycle, leaving the salts behind in the ocean. The water present on the surface of the ocean evaporates by the sun’s heat. This process of conversion of water from liquid state to vapour state is called evaporation. The sun warms up the surrounding air as well. Evaporation takes place faster in direct sunlight, than in a shady area. Evaporation also takes place from wet clothes, fields, ponds, lakes and rivers. Plants take in water to grow as well as to prepare their food.

They retain the water they need and release the excess water into the air as water vapour through the stomata of the leaves and the stem. This process is called transpiration. Thus, water is mainly evapo-transpirated to the air from land, water bodies and plants. The evaporated water is carried away by warm air.As the warm air moves higher from the surface of the Earth, it starts to cool down. It is because the water vapour present starts to condense to form tiny water droplets. These droplets float in the air and form cloud and fog. All these droplets collect to form bigger drops of water. Some of them may become too heavy to remain in the sky and fall down as rain. This process is known as precipitation. If the air is too cold, the water drops can become snow or hail and may settle on the top of a mountain. When these snow or hail melts, they can become part of a river or a stream. Thus, the water that is evaporated from the oceans or seas is again condensed to form water and fills up the rivers and seas. Rain water also seeps into the ground to form ground water. This circulation of water is called the water cycle.

Characteristics of Living Things

Characteristics of Living Things Human beings, animals and plants - all need food to survive.

Human beings, animals and plants - all need food to survive. Trees, creepers, birds, flowers, insects, animals and seeds are all livings things. Soil, bench, water, air and dry leaves are all non-livings things. The characteristics of livings things are: Livings Things Need Food Livings things need food to survive and grow. Food makes the body grow faster, and gives energy to the body to help it perform the life activities. For example, plants produce their own food by the process of photosynthesis, and grow. Animals depend on plants and other food for their survival. Livings Things Grow As livings things take food, they get more and more energy and grow faster. All living things grow continuously. Livings Things Respire Respiration is the process of breathing in and out. Living things take oxygen into the body as they breathe in and release carbon dioxide as they breathe out. The oxygen that enters the body during respiration helps the body to create energy from the food consumed. Some animals have special organs that help them in the process of respiration. For example, the gills of fish help them to absorb oxygen dissolved in water. Earthworms breathe through their skin. Plants have tiny pores on the leaves that help them to breathe. Plants respire day and night, but breathe out oxygen during the day. Plants release more oxygen while producing their food than they release during respiration. Livings Things Repond to Stimuli Stimulus is a change of some kind in the environment of a living organism. Every living thing responds in some way or the other to stimuli. The response in plants to stimulus can be observed easily.

For example, a plant called touch-me-not closes its leaves when touched. Also, the Evening Primrose blooms only during the night, while the flowers of Mentzelia Mollis close after sunset. Livings Things Excrete The process of eliminating wastes from the body is called excretion. Livings things need food, but they only absorb some amount of it for various processes, while the remaining food needs to be eliminated from the body. For example, plants eliminate harmful waste substances in the form of secretions such as resins and gums, whereas some plants store the harmful substances without any difficulty. Livings Things Reproduce All livings things reproduce. Some animals lay eggs, while others reproduce by giving birth to young ones. Plants produce seeds that can germinate into a new plant, but there are some, such as potato and rose plants, which reproduce through other parts. Livings Things Move Even though plants are livings things, they cannot move as their roots are fixed in the soil. However, the substances produced and required for their growth, such as water, minerals and food, move from one part of a plant to another. Some plants show some restricted movement. Animals have various modes of locomotion. Livings Things Die All livings things must die one day or another. Plants and animals die. All livings things possess these characteristics, whereas non-livings do not have these characteristics.

Types of Habitat

Types of Habitat Habitat is the place that is natural for the life and growth of an organism.

Terrestrial Habitat Habitat is the place that is natural for the life and growth of an organism. Now let us discuss how animals and plants adapt themselves for the terrestrial and aquatic habitats. Terrestrial habitat: All the deserts, mountains and forests and plain lands has come under terrestrial habitat. Camels have long legs for adaptation. Snakes and rats live in burrows and come out only during the night when it is cool. Xerophytes or desert plants shows some adaptations to sustain in the desert conditions. In desert plants, the leaves are either absent or reduced to spines as in cacti. The leaf-like structure seen in cactus is its stem and it carries photosynthesis. The roots grow deep into the soil for absorbing water. The reduced leaf and the thick waxy layer of stem minimise transpiration. The plants and animals in the mountain habitat show some adaptations. Most of the trees in cold mountains are cone shaped. The leaves are also very thin and look like needles For the sliding of water and snow during rains and snowfall. Animals in mountain areas have long hair and thick skin to protect them from cold climate. Thick fur all over Bodies of Yak and Snow Leopard protects them from the cold climate. The mountain goat, have strong hooves that help them run on the mountain slopes easily The animals living in the grasslands show some adaptations. Lions live in forests and prey on other animals, like deer, for food. The lions brown skin colour blends easily with the colour of dry grass in grasslands and helps in the catching the prey. They have strong claws to tear and eat their food. The eyes of the lion in front of its head helps in identifying the prey from long distances. Deeers  have long ears to help them sense the presence of a predator.

Deers  have eyes on the side of its head to look in all directions for danger and have long legs to run away from predator. Aquatic Habitat All the fresh water and marine water bodies , has come under terrestrial habitat. Fish have special features that help them to live in water. They have streamlined bodies, which reduce friction and allow them to move freely in water. Sea animals like the octopus and the squid do not have streamlined body as they stay deep insidethe ocean on the ocean bed, but make their body streamlined when they move in the water. Sea animals, like fish, octopus and squid have gills that help them to absorb the dissolved oxygen from the water they drink! Dolphins and whales have blowholes to breathe in air when they swim close to the surface of the water and there by stay inside the water for a long time without breathing. In general the aquatic plants have much smaller roots and helps the plant in holding on the surface. Stems are long and light.  Leaves and Submerged plants such as Ulva has narrow and ribbon-like leaves. These allow the plants to bend themselves in the direction of the flow of water.In milfoil, leaves are highly dissected, making water to easily flow without Frogs usually live in ponds and lakes. A frog can live both in water and on land. Frogs have strong hind legs to hop on land and webbed feet to swim in water. Frogs also have a membrane called the nictitating membrane on their eyes. This membrane helps protect their eyes inside water.

Habitat and Adaptation

Habitat and Adaptation Livings things exist in most places. Life exists even in open volcanoes.

Livings things exist in most places. Life exists even in open volcanoes. The term habitat refers to the surroundings where organisms live. Every habitat is home for a certain living creature. Habitat includes both living and non-living components. Plants and animals have different features that help them to survive in their own habitat. Habitat can be terrestrial or aquatic. Terrestrial habitat refers to the land where all plants and animals survive. It includes deserts, forests and grasslands, as well as coastal and mountain regions. For example, camels and cactus plants live in deserts only. Aquatic habitat refers to the water where plants and animals survive. Aquatic habitat includes rivers, ponds, lakes, ocean and swamps. For example, fish live in water. Adaptation: Plants and animals develop certain features or certain habits that help them survive in their surroundings, and this is known as adaption. Different living creatures adapt to their habitats in different ways. For example, fish have gills that help them to live in water and use the oxygen dissolve in it. Plants that live in water have special tissues that help to take in dissolved gas from water. For example, the ulva has ribbon-like leaves. It takes thousands of years for a livings being to adapt to its habitat.

Acclimatisation: The small adjustments by the body to overcome small changes in the surrounding atmosphere for a short period of time are called acclimatisation. The components in a habitat are broadly classified into two types. They are biotic and abiotic components. Biotic components include all the livings organisms in a habitat. Abiotic components include all the non-living things in a habitat. These include air, rocks, water, sunlight and heat. All livings things depend on the abiotic components for all their needs. The abiotic components are very useful for the survival of the biotic components in a habitat. For example, sprouting is the first step where a new plant grows from a seed. The sprouting of a seed depends on abiotic components such as air, water, light and heat. The population of some species of turtles has declined due to the change in the earth’s temperature. Some popular theories believe that dinosaurs became extinct because of the changes in the earth’s temperature millions of years ago.

Gait of Animals

Gait of Animals Earthworms move easily on hard and slippery surfaces.

Gait of earthworms Earthworms move easily on hard and slippery surfaces. Earthworms have tiny, stiff hair-like projections, called bristles, under their body. They grab the soil with the help of these bristles. Earthworms first stretch and then contract their muscles to move. As a result, they cover only a small distance with every move. A slimy substance secreted by the earthworm helps it to move. Earthworms eat their way through the soil. They throw away undigested food, which improves the quality of the soil. Gait of snails The outer skeleton of the snail, the shell, is made of calcium carbonate. The snail pulls this shell along as it moves. The snail can even hide its head inside the shell. The strong muscular foot below the shell can protrude. The under surface of the muscular foot is lubricated with mucus. Waves of muscular contractions along this surface help a snail move. The mucus also reduces the risk of injury from sharp objects. That is why snails can walk over sharp objects like blades without getting hurt. Gait of cockroaches The cockroach has three pairs of legs that help it to walk, and two pairs of wings that help it to fly. A cockroach moves its legs with the help of muscles near the limbs. It uses its breast muscles help to move its wings and fly. A cockroach can walk, fly and even climb. A cockroach can move in different terrains like sand and wired meshes because of the spines on its legs.

Gait of birds A bird has a body best suited for flying. Its wings are actually modified forelimbs. Birds can fly easily with the help of these bony forelimbs. Birds have light and hollow bones. The breast bones hold the muscles of flight that help them to flutter their wings. The tail controls the direction of flight. Birds have very strong shoulder bones. They don’t have the urinary bladder, which helps them to fly easily. They can walk and perch on trees with the help of their hind limbs. Gait of snakes Snakes move in S-shaped loops and in a zigzag manner. They cannot move in a straight line. They have difficulty in moving on very smooth surfaces. Snakes have a long back bone and many interconnected muscles that help them to slither. They have muscles connecting the backbone, ribs and skin. Snakes move in grass, sand and water. Snakes do not have arms or legs, but even then, they can climb trees. Gait of fish Fish have a streamlined body, which helps them move fast in water. Fish swim with the help of their fins. The tail moves from side to side, and helps the fish swim in the right direction. Some fish, however, move by bending their bodies from one side to another in quick succession, which produces a thrust that helps it move forward.