Category Science

What are various moves of animals?

          One of the key features of an animal is that it moves. It moves parts of its body when it opens its mouth, bends its neck or curls its tentacles. Most creatures also move about in their surroundings. They run, walk, jump, hop, slither, swim or fly. A few animals do not move about, at least as adults. Barnacles and mussels are stuck to seashore rocks. But they were mobile during their young, or larval, stages.

 

 

MOVING IN WATER

          Many animals live in either the sea or in rivers and lakes. Water is much denser than air and so resists movement more. To travel through water quickly, creatures must be smooth and streamlined so the water slips past them easily (submarines are a similar shape for this reason). Fish such as sharks swish their tails from side to side to provide the forward propulsive force for swimming. A fish’s fins and a dolphin’s flippers provide control for steering, slowing and going up or down. Penguins flap their wings and “fly” through the water.

 

 

 

MOVING IN AIR

          Only three groups of living animals truly fly in a sustained, controlled way—birds, bats and insects. Air is so thin it produces little resistance to movement, but it provides very little buoyancy either. Fliers flap their wings down to create a lifting force as well as back to push themselves forwards.

          Birds and bats have very thin, light bones to reduce body weight and so save on the energy needed to stay airborne. Even so, they must take in almost twice the amount of energy as food, compared to their ground-dwelling counterparts. The down flapping wing muscles in the chest are by far the largest muscles in the body of a bird or bat. Insects and bats control their movement by tilting or twisting their wings. Tiny insects like gnats and midges flap their wings nearly 1000 times each second to stay aloft. Birds control their flight by fanning and twisting their feathers. Hummingbirds are the fastest-flapping birds, with up to 80 wing beats each minute.

          All animal movement is made possible by muscles. A gorilla has about 640 muscles, making up about three-fifths of its body weight. A fast fish has 30-40 large muscles along each side of its body. Forming nine tenths of its body weight, they pull on the backbone to swish the tail from side to side.

 

MOVING ON LAND

          Large land animals move in a way suited to their habitat. On open plains, cheetahs, gazelles and antelopes have long legs and run very fast. Forest animals like deer are slower in straight-line speed, but more agile as they zigzag between trees. Other animals, such as squirrels and sloths, are adapted to moving in the trees themselves. They have long, sharp claws to grip the bark. Central and South American monkeys have long tails, called prehensile tails, that curl around branches like a fifth limb. Limbs are not vital for movement. Many snakes are limbless, yet they can slither on the ground, swim in water, and climb trees— and even glide!

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What senses do animals have?

          Most animals move around as they search for food, shelter or mates and avoid danger. So they have senses to detect what is going on around them. We have the same five main senses as many animals—sight, hearing, smell, taste and touch. Our main sense is sight. Compared to many animals, our eyes see clearly, in detail and in an especially wide range of colours. However, some animals have much better sight and other senses than we do. Some can even detect what we cannot, like tiny pulses of electricity.

          Some animals are nocturnal or active at night. They include cats, mice, bats, owls and moths. Their large eyes pick up as much of the faint light as possible. Animals that live in total darkness, like moles and cave salamanders or fish at the bottom of the sea have tiny eyes or none at all.

          The eye contains specialized nerve endings that detect patterns of light and send information about them to the brain. Other senses work in a similar way. In the ear, the eardrum is a thin piece of skin that vibrates when sounds hit it. Again, nerve endings detect these vibrations. Mammals, birds, lizards and frogs have eyes and ears on the head. However, some animals have them in other places on the body. A snail has eyes on flexible stalks. A clam has a row of small, simple eyes in the fleshy frill or mantle along the gaping edge of its shell. A grasshopper has eardrums on its knees.

 

 

SMELL AND TASTE

          Smell and taste are chemosenses. They are based on the presence of chemical substances, called odorants for smells and flavorants for tastes. We smell airborne odorants with the nose and taste flavorants in food and drink when they touch the tongue. Some animals have chemosensors on other parts of the body, too. A fly can taste with its mouthparts, its antennae (feelers) and its feet. A male moth’s feathery antennae can detect special floating chemicals given off by the female moth even if she is two or three kilometres away.

          A dog can smell scents up to 10,000 times weaker than we could detect.

          For animals in water, smell and taste are much the same. A shark has groups of chemosensors (taste buds) all around the inside of its mouth and also on the front of its snout. They are especially sensitive to blood and body fluids. A catfish has so many chemosensors in the skin all over its body that it is like a “living tongue”. Some fish including sharks, rays and elephant-snout fish (mormyrids) can detect the tiny electrical pulses given off by the active muscles of other animals. They use their electrosense to find prey in cloudy water or hiding in sand and mud.

 

 

     

 

         Electricity travels well in water, so many water animals have evolved to sense it. Electricity does not travel through air so land animals do not sense it. There are other senses that we lack and that we find difficult to imagine. Some animals migrate vast distances across featureless oceans with amazing accuracy. They may be able to sense Earth’s natural magnetic field or the way our planet’s downward pull of gravity varies slightly from place to place.

Picture Credit : Google

 

 

Describe Animal Feeding in detail?

          Of the five great kingdoms of living things, the animal kingdom is by far the largest. Scientists have identified at least two million different kinds or species, from tiny worms smaller than a full stop, to huge elephants and blue whales. There are almost certainly at least the same number of species still to be identified – mainly insects in tropical forests. The total number of animal species may be far higher: 10 million, or even more. The key features of an animal are that it has a body made of many microscopic cells and it gets its energy and nutrients by eating – that is, it takes in or consumes food. Most animals can also move about during all or part of their lives.

          Most animals ingest their food. This means they take food items into their bodies through an opening, the mouth, to be digested and absorbed inside. However a few creatures feed in more unusual ways. A tapeworm inside another animal’s gut is surrounded by ready-digested food. Also the tapeworm has no mouth. It simply soaks in or absorbs the nutrients through its very thin body surface.

 

MOUTHS

          There are almost as many different sizes and designs of animal mouth as there are different kinds of food. Most mammals like ourselves have teeth that can bite smaller pieces from a large food item and then chew the pieces into a soft pulp that is easily swallowed. But some mammals have few teeth—or none at all. The anteater collects its tiny food items of ants and termites by flicking out its long, sticky tongue. The vampire bat has front teeth like razor blades but it only uses them to slice a slit in its victim’s skin. Then it uses its tongue to lap up its meal of blood.

          Birds lack teeth, although they can peck powerfully with their strong, horn-covered beaks. Some birds have long, thin beaks like tweezers for probing into cracks or mud for small food items. Others have deep, short, powerful beaks that work like nutcrackers, for splitting seeds and nuts. Frogs also lack teeth for biting and chewing. They grab their food and gulp it down whole.

 

FOOD

          Most animals eat mainly plants or plant parts such as leaves, fruits, seeds, shoots and roots. They are herbivores. Some animals eat mainly the flesh of other creatures (sometimes their whole bodies). They are called carnivores. Other animals eat a wide range of both plant and animal food and are known as omnivores. A few animals, like dung beetles and crabs, eat dead or rotting food and wastes. They are detritivores.

          Food is broken down by the digestive system. This is usually a long tube coiled inside the animal’s body. The first part is the bag-like stomach with its muscular wall. It stores and squashes the meal. Next is the long intestine that absorbs the nutrients. Wastes pass out of the other end, the anus.

 

 

PREDATORS AND PARASITES

          A predator is an animal that hunts down and catches its victims, known as the prey. Some predators are large and fierce, like lions, wolves, crocodiles and sharks. Others are small but just as fierce, like shrews, newts, rag worms and diving beetles.

A parasite is an organism that takes its nourishment or shelter from another, the host. It may harm the host in the process but does not necessarily kill it. Fleas, lice, ticks and tapeworms are animal parasites. Mistletoe is a plant parasite of other plants.

          A few kinds of animals do not feed at all. A young mayfly leaves the water, splits its old skin and flies off as a winged adult. But it has no mouth and cannot eat. It mates and dies within a day.

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What do we exactly understand about a Tree?

          A tree is a large plant with a woody stem or trunk, covered with a layer of bark. There are two main groups of trees: broadleaves and the conifers. Broadleaved trees are flowering plants that produce fruits with seeds inside. Conifers produce cones, which carry seeds on the face of each of their scales.

          Many broadleaved trees are deciduous: their leaves drop in autumn, or, in hot countries, during the dry season. Some broadleaves and nearly all conifers are evergreen. Their leaves do fall, but not all at the same time. The palm tree, which grows in hot countries, is a different type of tree. It usually has no branches and only a few large leaves at its tip.

          Trees are a valuable resource. They give us fuel, timber, medicines, food, paper, rubber and even soap. Even more importantly, they take in carbon dioxide and give off oxygen, so maintaining the balance of gases in the atmosphere.

HOW A TREE LIVES

          Like all plants, a broadleaved tree has roots and a shoot. The shoot is made up of a trunk (its stem) and branches bearing leave buds and flowers. The trunk holds up the tree while the branches and twigs spread out the leaves so that they receive as much sunlight as possible. The leaves themselves grow in a spiral pattern to avoid shading. Water (blue arrow) is drawn up from the soil to the leaves through the sapwood. The leaves use the water and sunlight, as well as carbon dioxide in the air to make food by photosynthesis. This food (red arrow) passes from the leaves to all other parts of the tree through the inner bark.

          At the base of the tree, a network of roots spreads outwards, anchoring it into the ground. Behind the root tips lie the root hairs which soak up water and nutrients from the soil. A large tree may take up several hundreds of litres of water every day.

A TREE’S YEAR

          As spring arrives, the buds of the horse chestnut tree open, the shoots lengthen and the leaves unfold. Flowers blossom, ready for pollination. In summer, the leaves are fully open. The fruits, made up of a spiny casing with a large seed or “conker” inside, ripen and fall to the ground. During autumn, the leaves turn brown as food drains from them into the trunk. A scar forms at the base of each stalk and the leaves fall off. In winter, the tree is protected by its waterproof bark. The buds, next year’s leaves and flowers, are covered by scales.

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Unfold the mystery of Seeds and Fruits?

SEEDS AND FRUITS

          After male pollen grains have been carried to the female parts of a flower, the male and female cells join and begin to develop into the baby plant. The flower parts are no longer needed and they shrivel away, to be replaced by the developing seeds in the seed-head. A seed is usually accompanied by a food store for its early growth, neatly packaged inside a casing. Some plants, like orchids, produce many thousands of tiny seeds. An ear of wheat is a head of wheat seeds or grains. We grind them up to make flour.

          Seeds have a better chance of growing if away from the parent plant. If they fall next to the parent, they would be in its shade and would also compete with it for soil nutrients. For these reasons, seeds have many ways of being spread far and wide.

 

FRUITS AND NUTS

          A fruit is the protective case around a seed. Some fruits are very light, like the feathery “parachutes” of the dandelion. They blow away in the wind. Some fall into water and float to a new place, like the coconut. A nut has an especially tough outer case. Animals may crack some nuts and eat the seeds within, but they also drop many as they feed. A squirrel buries nuts such as acorns, but may forget to dig them up, so in effect it has planted new oak trees! Some fruits have juicy, tasty flesh. These are known by the everyday name of “fruits”. The fruity part attracts animals to eat it. The seeds are spilled or pass through the animal’s guts to emerge unharmed and far away.

 

 

     

    A seed germinates, or begins to grow, only when conditions are suitable. This usually requires moisture of some kind, the right temperature, and perhaps darkness, which means the seed, is buried in the soil. Some seeds like those of the ironwood tree do not germinate unless they have been scorched by fire. This usually means many plants have burned away so the ground is bare and ready for new life. Other seeds do not germinate until after they have been cracked by frost and then warmed slightly, that is, when winter is over and spring has arrived. When conditions are right, the baby plant begins to grow using its store of food in the seed-leaves, or cotyledons. It splits its case, sends roots down into the soil and grows its shoot up towards the light.

 

FUNGI

          Mushrooms, toadstools, brackets, yeasts, moulds and mildews are all fungi. They form one of the five great groups or kingdoms of living things. Fungi are rotters. They grow networks of thin, pale threads, called hyphae, into the bodies of dead and dying plants and animals. The threads cause the body to decompose. They then absorb the released nutrients through their surface. Like bacteria, fungi are nature’s recyclers. They return the nutrients in dead animal and plant matter or animal droppings back into the soil.

 

          A fungus’s network of threads is known as the mycelium. It is usually hidden in the soil, inside a dead animal’s body or under a dying tree’s bark. So we rarely notice fungi at work. We are more likely to notice them when they reproduce. They do this by growing fruiting bodies. Many of these are shaped like umbrellas—we call them mushrooms and toadstools. The presence of a mushroom indicates a network of hyphae in the soil below, rotting down and absorbing nutrients. The mushroom’s top, or cap, releases millions of tiny fungal spores that blow away in the wind.

Picture Credit : Google

 

 

How do plants live?

          A plant may not look lively and active. But inside its millions of microscopic cells, thousands of chemical changes take place as part of the plant’s life processes. Like an animal’s body, a plant’s body has many specialized parts for different jobs. The roots take in water, minerals, salts and other substances from the soil in which the plant grows. The stiff stem holds the main parts of the plant above the surface, away from animals on the ground that might eat it, and above other plants so that the leaves can catch more sunlight.

 

          A plant’s leaves are “light-powered food factories”. They are broad and flat so that as much light as possible falls on them. A green substance called chlorophyll in the leaves catches or absorbs the energy in light. It uses this energy to make a chemical reaction. Water, taken up from the soil, and carbon dioxide, taken in from the air, join together to form sugar, which contains lots of energy in chemical form. The plant then uses the sugar to power its life activities. The process is called photosynthesis —a word meaning “making with light”.

          The carbon dioxide for photosynthesis comes from the air. It seeps into the leaf through tiny holes in its lower surface, known as stomata. In addition to sugar, photosynthesis also produces oxygen, which seeps out into the air. Living things including ourselves need oxygen to survive. Plants help to top up its level in the air.

FLOWERS AND POLLEN

          A plant’s flower is designed to reproduce—make seeds which grow into new plants. A typical flowering plant has both male and female parts. The male parts make tiny particles, pollen grains, which look like fine yellow powder. Each grain contains a male cell. Pollen is produced in bag-like anthers on stalks, called filaments. The female cells or ovules (eggs) are in the ovary, a fleshy part at the flower’s base. A taller part, called the style, sticks up from this, with the stigma at its top. Pollen must travel from the anthers of one flower to the stigma of another of the same kind, so the male and female cells can join and develop into seeds.

          The transfer of pollen is called pollination. Some pollen grains are light and balloon-like and are blown by the wind. Others are sticky and carried by animals. To attract animals, the flower has colourful petals and a strong scent and makes sugary liquid called nectar. When animals come to drink the nectar, the pollen sticks on them. It brushes off at the next flower on to the stigma. A tube grows from the pollen grain down the style to the ovary. The male cell moves down this to join the ovule.

Picture Credit : Google