NCERT summary for UPSC CSE - GS (Class V - Environmental studies - Looking Around)
Super senses :
As the ants move, they leave a smell on the ground. The other ants follow the smell to find the way.
Some male insects can recognize their females by their smell.
Silk worms can find female worm from many kilometers away by her smell.
Mosquitoes can find you by the smell of your body. They also find you by the smell of the sole of your feet and the heat of your body.
Dogs mark out their own area on the road. They can make out if another dog has come into their area by the smell of it’s urine or potty (latrine).
It is believed that animals that are awake in the daytime can see some colour. Those animals that are awake at night can see things only in black and white colour.
Snakes do not have external ears. They only feel the vibrations on the ground.
Sounds send messages
High upon a tree, a languar warns others of dangers like a tiger or a leopard. The languar does this by making a special warning call.
Birds also give alarm calls to warn about the danger. Some birds even have different sounds for different kinds of dangers. For example, there is a different warning call if the enemy is coming from the sky or if the enemy is on the ground.
Fishes give alarm calls by electric signals.
Some animals start behaving in a different way when an earthquake or storm is about to come. People who live in forests and can observe such behaviour of animals come to know of the danger.
In December 2004, few tribes that lived in the forests of the andaman islands noticed the animals behaving in a different manner. They guessed some danger. So they moved away to the safer part of the island. Soon after, the islands were hit by the tsunami but these people were saved.
Dolphins also make different sounds to give messages to each other. Scientist believe that many animals have a special language of their own.
A tiger can see six times better at night than most of us.
The tiger’s whiskers are very sensitive and can sense the movements or vibrations in air. They help the tiger move in the dark and find its prey.
A tiger’s sense of hearing is so sharp that it can make out the difference between the rustling of leaves and the sound of an animal moving on the grass. The ears of the tiger can move in different directions and this helps to catch the sounds from all around.
Tigers make different sounds for different purposes like when it is angry or to call out to a tigress. It can also roar or snarl. It’s roar can be heard up to 3 kilometers away.
Each tiger has it’s own area which may cover several kilometers. Tigers mark their area with their urine. A tiger can at once come to know if there is another tiger in it’s area by the smell of the urine.A tiger will avoid going into another tiger’s area.
A Snake Charmer’s story :
Of the many kinds of snakes found in our country. Only four types of snakes are poisonous.
They are :
2. Common Krait
3. Russel’s viper (Duboiya)
4. Saw-scaled Viper (Afai)
A snake has two hallow teeth (fangs). When it bites, the poison enters the person’s body through the fangs. There is a medicine for snake bites.
The medicine is made from snake’ poison and is available in all government hospitals.
Seeds and seeds :
Plants which hunt
There are some plants which trap and eat frogs, insects and even mice. The pitcher Plant (Nepenthese) is one such plant. It is found in Australia, Indonesia and Meghalaya in India. It has a pitcher like shape and the mouth is covered by a leaf. The plant has a special smell that attracts insects to it. When the insects lands on the mouth of the plant, it gets trapped and cannot get out.
In 1948, One day George Mestral came back from walk with his dog. He was amazed to find seeds sticking all over his clothes and on his dog’s fur. He wondered what made them stick. So he observed these seeds under a microscope. He saw that the seeds had many tiny hooks which got stuck to clothes or fur. This gave Mestral the idea of making velcro. He made a material with similar tiny hooks that would stick. Velcro is used to stick together many things - clothes, shoes, bags, belts and many more. Mestral took inspiration from nature.
A Treat for Mosquitoes:
Medicine for Malaria
From early times, the dried and powdered bark of the Cinchona tree was used to make a medicine for malaria. Earlier people used to boil the bark powder and strain the water which was given to patients. Now tablets are made from this.
Mosquitoes spread malaria, dengue and chikungunya.
Don’t let water collect around house. Fill up pits.
Keep the water pots, coolers and tanks clean. They should be dried every week.
Use mosquito nets to protect yourself.
Spray kerosene if water has collected at some place.
Anaemia common in Delhi school
17 November, 2007 - thousands of children studying in the municipal corporation schools in Delhi suffer from anaemia. This is affecting both their physical as well as mental health. Due to anaemia, children do not grow well, and their energy levels are low. This also affects their ability to study properly. Now health check ups are being done in schools and health cards are being made for all children. Anaemic children are also being given iron tablets.
What if it finishes :
Treasures from the earth
It is not easy to find out where oil is, deep down below the earth. Scientists use special techniques and machines to find this out. Then through pipes and machines petroleum is pumped up. This oil is smelly, thick, dark coloured liquid. It contains many things mixed in it. To clean and separate these, it is sent to a refinery.
It is from this ‘petroleum’ or oil that we get kerosene, diesel, petrol, engine oil and fuel for aircraft. LPG(cooking gas), Wax, coaltar and grease are also obtained from this.
It is also used in making several other things like plastics and paints.
A shelter so high :
The world famous pashmina
It is believed that a pashmina shawl is as warm as six sweaters. It is very thin yet very warm. The goats from which the soft pashmina wool is collected, are found on very high altitudes of 5000 meters. In winter, the temperature here drops below 0 degrees. a coat of warm hair grows on the goat’s body which protects if from extreme cold. The goats shed some of their hair (fur) in summer. This hair is so fine that six of these would be as thick as one hair of yours.
The fine hair cannot be woven on machines and so weavers of kashmir make these shawls by hand. This is a long and difficult process. After almost 250 hours of weaving, one plain pashmina shawl is made.