Environment and Ecology

            Human civilization has developed very slowly. In the ancient times man was totally dependent on nature for his needs but as he learnt abut agriculture he started interfering with the laws of nature. He shaved off the forests for agriculture and tamed many wild animals for his food and clothing. He left the caves and started living in houses. With the development in man’s lifestyle, several civilizations of Summaries, Egypt and Indus valley spread over the vast areas of the world. It is a general belief that man has conquered the nature but still he cannot control natural disasters.

Eating relations in a community

            All the living beings on the earth utilize solar energy and get essential elements from atmosphere, lithosphere and hydrosphere. Animals and plants either depend on plants or on other animals for their food. A balance exists between living and non living things in the nature. Whenever any element of nature increases or decreases in large proportions, ecological balance gets disturbed. The study which deals with the relationships of life forms with each other and with their surroundings is called ecology. A group of animals living in a particular physical environment is called ecosystem.

            Today rapid industrialization and ever increasing human requirements have disturbed these natural elements and created an ecological imbalance. Increasing population, emission of carbon dioxide and other toxic gases by factories and vehicles, occurrence of acid rain, nuclear tests and poisonous chemicals have posed a serious threat to the ecological balance. The entire earth and its inhabitants are affected by pollution. Life on earth is endangered. Now, the man ahs realized the need of ecological conservation and safety of environment. Public awareness is being created for the protection of life on the earth. Many programmes for a better environment and conservation of natural resources are being carried out all over the world. The scientific conservation programmes are mainly based on the principles of ecology. We can get a better environment only when every body, specially the children, becomes aware about it.

            To study the ecosystem, it is necessary for us to acquire deep knowledge of the trees, plants, ponds, rivers, lakes; air, water and land; crops and creatures; marine animals, etc. this way we will be able to make our ecosystem even better. It is our duty as well as responsibility to ensure the safety of our food chains.

Can Animals identify different Colors?

            We know that animals can see things like us. But can they distinguish between different colors like human beings? To find an answer to this question, scientists have conducted a number of experiments on different animals like cats, dogs, apes and bees.

            Experimentally, it has been found that dogs cannot distinguish between different colors. Some dogs were given eatables of different colors but the variation in colors had no affecting them. This has proved that dogs cannot identify different colors. Some experiments of this type were found to be color blind.

            Besides man, ape is the only mammal, which can differentiate between different colors. All other mammals are color blind.

            The honey bees also have this exceptional characteristic. They can differentiate between different colors. However, they cannot identify the red color. Red looks like black to them. It is on the basis of identification of colors that these bees are attracted towards the flowers of different colors from which they collect honey. The honey bees are also capable of seeing the ultraviolet rays tat even human beings cannot see.

A honey bee can see ultraviolet rays but it fail to identify red color

            To test their power of color vision, the bees were shown two cards- blue and red. A little syrup was placed on the blue care, whereas the red card was without it. The honey bees gathered on the blue card. Then the blue card, without any syrup on it was kept at a different place. The bees reached there as well. This proved that they could distinguish between different colors.

            Even birds can differentiate between different colors. The color of the male birds is more attractive than those of the females. These colors are used to the attract the female. It has been observed that birds can identify all the colors of the rainbow.

            Generally animals have no need to distinguish between colors because most of them hunt by night and do not depend on color. However, they have a greater power of smell and as such their color blindness does not handicap them.

Which is the Birds prey?

            The birds, which feed on other animals, are called the birds of prey. They catch and feed on animals that are usually smaller than them. They may catch their prey anywhere on the ground, in air or in water. But not all birds bother to the flesh of dead animals. Do you know which the birds of prey are?

Eagle, a bird of prey

            The common birds of prey are- buzzards, eagles, falcons, harriers, hawks, kestrels, vultures and woodpeckers. Owls also catch smaller animals and feed on the out they are put in a different category. Most of the birds of prey are brown-colored. They are found in all the continents except Antarctica. They kill they prey with their strong sharp talons, and pluck and tear the flesh with their narrow, hooked beaks. These birds normally swallow huge chunks of food and regurgitate the pellets of indigestible matter.

            The birds of prey attack in two ways. Kestrel hunts by hovering over open ground and then plunging down on its prey before it can escape. Falcon stoops or dives its head first at its prey and catches it in its talons. Eagles are powerful and soaring birds of prey.

            Some eagles hide in a tree and wait for their prey to wander into a clearing. Carrion eaters soar on outstretched wings at considerable heights for hour’s together ad peering down for animals already dead or the ones about to die. In contrast to it the small birds of prey like the sparrow hawk dash at high speed through trees to sprig surprise on a small creature. The birds of prey also kill with their feet. Although some use the beak for the purpose, yet the sharp, curved talons of the feet are the main killing weapons. The rear and inner talons are usually larger than the middle or outer one. These help the birds to exert a strong pincer grip on the prey.

            The birds of prey hunt a variety of animals such as rabbits, hares, grouses, fishes and other smaller birds.

Why do Giraffes have a Long Neck?

            Giraffe is the tallest land animal in the world, but one mystery, which baffles scientist, is how it got its long neck. A famous French zoologist jean Baptist de Lamarck proposed a theory that at one time giraffe’s neck was much shorter than what it is now. It had to raise its neck to eat the leaves of the trees. According to Lamarck, the part of the body, which is used most, develops most. The giraffe had to raise its neck time and again to reach the upper branches of trees when the leaves on lower branches of trees when the leaves on lower branches were eaten away. The excessive use of the neck resulted in its gradual increase. The successive generations of the giraffe started having longer necks and finally today’s long-necked giraffe emerged. The male giraffes grow up to height of 5.5 meters and weigh more than 1,000 kilograms. It is herbivore ad chews its food I spare time. The formation of giraffe’s body is such that its mouth can easily reach the leaves of high trees. Its tongue is about 45 centimeters long and constructed in such a way that it can eat even the leaves of thorny plants. It has a long upper lip that helps it wrench off many leaves at a time.

Giraffe

            The color of giraffes resembles the shadow of the trees and as such it cannot be easily spotted by its enemies. It is usually yellowish-brown in color and has highly sensitive ears.

            The giraffe’s ears can pick the faintest sounds, but it is nearly incapable of uttering sounds. The word nearly has been used because some of the female giraffes and their young do have been found mooing like cow or ox in the zoological parks but most of them do not utter sound. The reason for this inability lies in the underdevelopment of its voice box or larynx. Probably due to this reason, it has a keen sense of smell and sight. If attacked, it can run at a speed of 45 kilometers per hour for an extended period of time without getting tired. As far as fast running is concerned, it can bet even the fastest of horses. When some other animal attacks it, it retaliates with the help f its head and hind legs. As its eyes are far above the ground, it can easily see predators long before they can get close enough to attack. That is why even the lion has to be very cautious while attacking a giraffe. Lions always attack it form behind because giraffes strike with its head like a hammer.

How does a Wall Lizard Get rid of its Tail?

            We may have noticed that sometimes when you try to kill a lizard, you only manage to cut off its tail. When an enemy attacks a wall lizard it often flees, leaving behind some portion of its tail. The detached tail keeps wagging for some time. This confused the enemy and the wall lizard escapes. That is how it protects itself forming its enemies.

            The wall lizard can easily detach a portion of its tail at its will. The bones in its tail are joined together loosely, so that any portion of the tail can be separated easily from the main body. When the tail is separated, it does not lose much blood because the ends of the blood vessels are almost sealed. It is, therefore, possible for the wall lizard to get rid of its tail. The lizard soon grows a new tail.

            Scientists have studied more than 3,000 species of lizards till date. It has been found that their bodies are usually divided into three distinct parts- head, trunk and tail. Most species have four legs. Although most lizards are hatched from eggs, a few are born directly. Most lizards feed on insects. A few of the larger species are more than 3 meters long. They are quite frightening with one blow of their long, strong tails. These lizards are mostly found in tropical countries. A number of African species live in tropical forests where they climb trees. Some of them have flattened flaps of skin, which can be stretched down between hind and forelimbs to jump from tree to tree. Lizards can run fast, and some can swim or even glide through the air.

            Like lizards, crabs and lobsters are also able to get rid of their legs in a way similar to the lizard detaching its tail. When a fish catches the leg of a lobster, it jerks away its leg and escapes. These are the defense mechanisms that enable these animals to survive.

What are Mammals?

            Mammals are vertebrates or animals with backbones. They have large brains and a keen awareness of their surroundings. They are warm-blooded and have their skin covered with hair. Mammals give birth to their young ones, except for egg-lying platypus and spiny anteater, and suckle milk for the milk glands of females. You will be surprised to know that many animals, which are otherwise very different from one another, come under this category. For example, the cow, seal and bat have nothing in common, yet they come under the category of the mammals. Man is a mammal too.

Wolf

Lion

Cheetah

Polar Bear

            Many of the mammals are very peculiar. Some of these live on the land, some on trees while some others burrow holes inside the earth. There are some that live in water, also.

            Some of them are carnivorous while others are herbivorous. Some mammals are both carnivorous and herbivorous.

            Most of the time they live on the ground. The dugong, dolphin, whale etc. are mammals that live in water. Amongst the flying mammals are the bat and colugo.

            Platypus is another peculiar mammal, which does not give birth to its young ones but lays eggs. It is found in Australia. Pangolin is a mammal that does not have teeth and lives on ants. The wolf, lion, cheetah, bear, cat, seal- all are mammals. There are about 4000 distinct species of mammals – the ones given above are just a few of them.

How Fast Can Animals Run?

            A few years ago, the American scientist and explorer, Roy Chapman Andrews came to India as the leader of an expedition team. One day as he was driving a jeep near the India Nepal border, he saw a Cheetah. Startled by the jeep, the Cheetah began to run, and he gave it a chase. In spite of driving at a speed of 80 kilometers per hour, he still lagged behind. Even at a speed of 100 kilometers per hour, the animal was ahead of the jeep before it finally disappeared into the jungle.

Cheetah, the fastest land animal, can run up to a speed of 96-101 kilometers per hour on a level ground

            Over short distances, i.e. up to 550 meters or 600 yards the cheetah or a hunting leopard in the open plains of east Africa, Iran, India, Turkemenia and Afghanistan can attain a maximum speed of 96-101 kilometers per hour 60-63 miles. Blackbuck comes next. It is a kind of deer. The third place goes to Mongolian gazelle and the pronghorn- the two species of deer. They can run at a speed of 95 kilometers 60 miles per hour. Lion occupies the fourth place. It can run at a speed of 88 kilometers 55 miles per hour.

            Rabbit and fox can run at a speed of about 75 kilometers 47 miles per hour. Horse, zebra and grey-hound can run at the speed of 64 kilometers 40 miles per hour. Buffalo and hare can run at the speed of 55 kilometers per hour, while giraffe and wolf at a speed of 50 kilometers per hour. The elephant can run at about 40 kilometers per hour. Kangaroo and sheep can run at a speed of 64 and 25 kilometers respectively while camel and pig can run at 18 kilometers per hour. The speeds of the four-legged animals given above are based on the conclusions of a large number of researchers.

            These animals cannot sustain these speeds for a very long time. At the most, they can cover a distance of a few hundred meters at these speeds.