NCERT Solutions for Class 5 EVS Chapter 1

Sense organs are the five natural organs which are the window to the world. It is through them that we receive information about the world around us. These sense organs are Eyes, ear, nose, tongue, and skin. The senses which we get from them are- sight, hear, smell, taste, and touch.

Ants: They have a very powerful sense of smell as they can recognize each other and walk in a line using this sense.
Mosquitoes: Mosquitoes have a very powerful sense of smell. They can find us by our smell that is why they can be seen around us every time.
Eagle: Eagle has sharp sense of sight. It can see things from a distance of almost eight meters, what we can see from a distance of two meters. They have very sharp eyes.

Mosquito have a sharp sense of smell which helps them find a person. They can find a person by the smell of his body.

Dogs have their own areas which they mark out by the smell of their urine. They are able to recognize their area by sniffing here and there.

Owl is the only bird having its eyes in front of its head.

Penguins, crow, sparrow, eagle are some birds with eyes on either side of head.

As ants move, they leave a smell on the ground. The ants walk in a straight line because they follow the scent the leader left behind. Once the ants find food and head back to their area, they lay down another trail of pheromones there which allows others to pick up their scent and follow the same route. Thus they follow the smell to find the way and move in a line.

Bee, snakes Bear, rats, squirrels, lizards etc. sleep during winters. It is called hibernation.

Some birds, like kites, eagles, vultures can see four times as far as we can.These birds can see things from a distance of 8 meters what we can see from a distance of 2 meters. They uses this super sense to catch their prey.

Many non-bird species also communicate using sound. Monkeys cry out a warning when a predator is near, giving the other members of the troop a chance to escape. Some monkeys even have different calls to indicate different predators. Bullfrogs croak to attract female frogs as mates.Animals use sound to make a special warning. Birds also use sound to warn about the danger. Fishes give alarm call by electric signals.

Tiger has a very sharp sense of hearing. It can differentiate between the sound of the rustling of leaves and sounds of animals moving on the grass. His ears can move in different directions to catch sounds from all around. The tiger’s sense of hearing is the most acute all its senses and is mainly used for hunting. Their ears are capable of rotating, similar to a radar dish, to detect the origins of various sounds such as the high-frequency sounds produced by prey in the dense forest undergrowth.

Hunters and poachers are the people who catch and kill animals. They kill them for their skin, bones, teeth and horn etc. Elephants are killed for their tusk, rhinoceros for their horn. Tigers, crocodiles are killed for their skin and mask deer for scent.
Poaching is the illegal hunting, killing and capturing of wild animals. People poach animals for their products, such as hide, ivory, horn, teeth and bone. Large mammals such as the tiger, rhinoceros, lion and elephant once faced the diverse possibility of complete extinction due to uncontrolled hunting and poaching.

The reason for the decreasing number of some animals is hunting and poaching. The animals are hunted on large scale for their skin, bone, teeth etc. To protect these animals, the government has made forests as protected areas. They have made national parks, wildlife sanctuaries and biospheres, for example Jim Corbett national park in Uttarakhand and Ghana in Bharatpur district of Rajasthan. In these areas nobody can hunt the animals and destroy jungles.

The tiger’s sense of hearing is the most sharp of all its senses and is mainly used for hunting. Their ears are capable of rotating, similar to a radar dish, to sense various sounds such as the high-frequency sounds that are produced by prey in the dense forest bushes. Tigers mainly depend on their sense of sight and hearing rather than on smell when hunting prey. They carefully follow their prey from the back to get as close as possible to their unaware prey. Then they attempt to take down their prey with a powerful bite on the neck and/ or throat.

Dogs are used in rescue operations because dogs are good smellers, have sharp ears and have sharp eye sight too. This is because dogs have advanced senses – sense of smell and scent so they can detect humans easily who might need to be rescued in disaster situations like fire, floods and may not be easily visible to the fire fighters or police. Search dogs are trained to smell drugs, fire arms/explosives and money in large quantities.

A mosquito moves toward human and bites even in a dark room as it has the ability to smell human odour, detect body heat and body humidity. Mosquitoes also bite in dark because they avoid exposure to sunlight which makes them dehydrated and kills them. Mosquitoes therefore do not need to see us to bite as they sense the heat which is released from our body and locate us even in dark room.

Dogs mark out their own area .Many animals use urine, and sometimes even faeces, to mark the area that they consider to be theirs or as their territory. Territory marking lets other animals of the same species, know that someone is present. They can make out if another dog has come into their area by the smell of its urine or potty (latrine).

Few facts about owls are:
• Owls have large eyes which are fixed.
• They cannot move their eyes
• Owls are nocturnal as they are active at night.
• Their neck is flexible and they can turn their head almost around

Different animals can see different kinds of colour from a broad range of spectrums. Some see very little colour, while creatures such as bees and butterflies see more than us as humans. Animals cannot see as many colours as we can. It is believed that animals that are awake in the day time can see some colours. Those animals that are awake at night can see things only in black and white colours.

The main threats to the tiger are:
• hunting,
• poaching,
• habitat loss,
• deforestation and a shortage of its prey

i. Langur is an animal which lives on the top of the tree. It warns other animals about dangers like a tiger or leopard. by making special warning call.
ii. Sloth looks like a bear. It spends almost 17 hours a day sleeping while hanging upside down on a tree branch. The sloth eats the leaves of the same tree. Sloth lives for about 40 years and that time they move around only on eight trees. Once a week it comes down from the tree to relieve itself.

Most of the birds have their eyes on either side of the head. Their eyes can focus on two different things at a time. When they look straight ahead, both their eyes focus on the same object.

Birds give alarm calls to warn about the danger. Some birds 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.

Animals have different sleeping patterns depending upon their need to ear and conserve energy.
For example –cow sleeps for 4 hours whereas a goat sleeps for 5.3 hours.

Big animals eat large amount of food because they need more energy. So they need plenty of time to eat and digest their food. It is for this reason that they sleep for a short period. Bigger animals generally tend to sleep less because they have to spend so much time eating. Elephants can eat up to 300 kilograms of food a day, so obviously it takes a long time for the trunk to get all that into their mouths, and that leaves less time for sleep. For the most part, giraffes tend to sleep during the night, although they do get in some quick naps throughout the day.

Sleeping habits of the animals vary a lot .Like us animals also sleep to take rest.
• Some big animals like elephants and giraffes sleep for a short period while other big animals like Python and Tigers sleep for more than 15 hours.
• Small animals sleep for longer hours because they spend more energy than large animals.
• Dogs and Cats close their eyes to sleep.
• Horse sleep while standing.
• Owls sleep during day time.
• Bats sleep hanging upside down.
• Dolphin sleeps with one eye open.

1. A Tiger can see six times better at night than us.
2. A tiger’s sense of hearing is so sharp.
3. The ears of the tiger can move in different directions and this helps to catch sounds from all around.
4. Tigers make different sounds for different purposes.
5. Its roar can be heard up to 3 km away.
6. The tiger’s whiskers are very sensitive they help the tiger to move.
7. Tigers mark their area with their urine

Endangered animals:
1. These are species which are in danger of extinction.
2. The survival of such species is difficult if the negative factors that have led to decline in their
population continue.
3. Black buck, crocodile, Indian wild ass, lion tailed macaque etc., are examples of endangered species.
Extinct species:
1. These are species which are found no longer
2. A species may be extinct from a local area, region, country, continent or the entire earth.
3. Asiatic cheetah, pink head duck are examples of extinct species.

Birds enjoy a sharper vision than humans. Birds can see certain light frequencies–including ultraviolet that humans cannot see. In fact, many songbirds have feathers that reflect ultraviolet light. This light is used to communicate their species, gender etc.

Snakes do not have external ears (which can be seen). They only feel the vibrations on the ground.

Some animals go into a long, deep sleep in certain seasons. Then they are not seen for many months. Some animals sleep all winter. It is a very deep sleep called hibernation. They need little or no food. Bears and chipmunks hibernate. Many animals prepare themselves for the winter by storing up food to eat later and they hibernate.

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.

Various features of a tiger are:
• A tiger’s sense of hearing is very sharp so 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. Its roar can be heard up to 3 kilometres away.
• 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 which help the tiger move in the dark and find its prey.
• Each tiger has its 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 its area by the smell of the urine. A tiger will avoid going into another tiger’s area.
• The tiger is one of the most alert animals.

Humans are responsible for causing changes in the environment that hurt animals and plant species. We bring exotic species into habitats. All of these activities take resources and habitats away from plants and animals. Human activity often changes or destroys the habitats that plants and animals need to survive. Human beings are thus a threat to animals. Due to continuous poaching, many animals have either become extinct or have come to the stage of extinction. Further, growing human interference and destruction of forests has forced dangers to these animals.

A national park is a park which is in use for conservation purposes. It is created and protected by national governments. National parks are areas that aim to protect the natural environment. They are also involved in public recreation and enjoyment activities. In a national park, the landscapes and its flora and fauna are present in their natural state.

The steps that have been taken by our government to protect wild life in our country are:
(i) survey and collect all the information about wildlife, especially, their number and growth.
(ii) protect habitat by protecting forests.
(iii) delimit the areas of their natural habitat.
(iv) protect wildlife from pollution and from natural hazards.

If the tigers lose their whiskers then they:
• will not be able to sense objects near them because as the tiger walks its whiskers come forward and increase their sensing ability which help them to register very small changes in air pressure that occur as the Tiger nears an object. Along with excellent night vision, this helps them to avoid objects. Whiskers give messages that could be important information for a Tiger – it may be a clue when an animal it would like to eat is rushing past it. In other words, it could help them hunt in the dark.
• Will not be able to catch their prey as they use their whiskers to catch prey .Whiskers can detect the prey and help them in hunting. Whiskers also come forward when prey is caught in the jaws.

Tigers have night vision that is six times better than that of humans, which helps them move and hunt successfully in the dark. Tigers have more rods which are responsible for visual insight for shapes in their eyes than cones which are responsible for colour vision that assist them with their night vision.