Imagine what would the world be if there were no animals in the jungles, no birds chirping in the morning, no honey bees making honey, no fishes in the ponds, no trees, flowers and fruits. Our surroundings would be empty. 

Animals play a very important role in our life. The surroundings in which they live and grow is called Environment. The animal kingdom is very large and has a variety of animals big and small which are found on land, in water and in air. They have different shapes and size. We study about these animals in the branch of Biology called Zoology. Since these animals are our natural resources, we should try our best to protect them and see that they are not killed. They need our love and care.
 

Animals are very helpful to us  

• Animals, which carry loads, are horses, elephants, camels and bullocks.   Bullock and camel carts are very popular in some parts of the country.
• Farm animals like cows and buffalos give us milk. Camel milk is also used in some parts of the country.
• We eat the meat of many animals like goat, chicken, pig, etc. 
• Animals like dogs, cats and parrots may also be kept as pets in our homes. 
• Do you know that the silken and woolen garments, which you wear, are also obtained from animals and not plants? Sheep and yaks give us wool while silk is obtained from a small insect called silkworm. 
• Honeybees give us honey. 
• Good manure is made from animal dung and dead animals.
• Leather is also nothing but cured and processed animal skin. Ancient people used to cover their bodies using animal skins. Jackets, fur caps, coats and gloves, purses, etc. are all made from animal skin.

 

Animals are unique in their looks and characteristics. Observe some animals in your locality. Do they have the same number of legs and a similar body structure? Compare your body parts with theirs. Each type is different from the other. A lion is very different from a cow and a dog does not have the same features as a cat. All living things have some common characteristics.

How do we classify animals? They are classified on basis of the different types of characteristics they posses.

1. Invertebrates

Animals which don't have a backbone or skeleton, are called Invertebrates.

• Microbes (small organisms, e.g. Amoeba)
• Insects  Adult insects typically have three pairs of legs, one pair of antennae and in most instances, two pairs of wings.

Animals which have a backbone or a bony skeleton, are called vertebrates.

• Birds are members of a group of animals called vertebrates, which possess a spinal column or backbone; birds develop from embryos in eggs outside of the mother's body.
• Fishes and all diverse group of animals that live and breathe in water. All fishes are vertebrates (animals with backbones) with gills for breathing. Most fishes have fins for swimming, scales for protection and a streamlined body for moving easily through the water. 
• Reptiles are vertebrates that have a backbone with tough, dry skin covered with horny scales. Some of the most widespread living reptiles are turtles, lizards, snakes, crocodiles and alligators. 
• Amphibians are animal with moist, hairless skin through which water can pass in and out, e.g. frog. They can live on land and in water.
• Mammals have entirely different habits and behaviours. Humans are mammals. They give birth to their young directly, and don't lay eggs. According to the suitability of their environment, they have different organs for movement, feeding and breathing.

Body Organs of Animals

a. Organs of Movement

Animals can move in different ways from one place to another in search of food and shelter and have different types of body organs.

Land Animals

Land animals have four limbs.

• Fore limbs--the two limbs in front are called fore limbs.
• Hind limbs--the two at the back are known as hind limbs.
• Some use all four limbs to walk, run or jump while some use only hind limbs, e.g. kangaroo.
• Snakes, lizards, crocodile move by crawling, but they do have limbs. Snakes do not have legs.

They have fins, webbed feet and paddle-like limbs.

• Fins--fishes swim with the help of fins.
• Webbed toes-- frogs swim with webbed toes, when on land they use hind legs to jump.
• Paddle-like limbs--tortoise use four paddle-like limbs to push water.
• Flippers--penguins use two fore limbs as flippers to push water forwards.

Birds (Animals of the air)

Birds have wings, which help in flying. The fore limbs (front) of birds are converted into wings, which have feathers.
Flightless birds--some birds are unable to fly because their wings are to weak for flying like for e.g. kiwi, ostrich, emu and rhea.

Insects

Some insects have one or two pairs of wings for flying e.g. butterfly. The wings are different from those of birds, as they have no feathers. They are made of tiny colored scales. Some have six legs for movement, e.g. cockroaches and ants. Grasshoppers use hind legs.

Why is movement important for animals?

• To build resting places like nests etc.
• To search for food
• To protect themselves from enemies.

b.   Feeding Organs

Animals eat different types of food and have different types of feeding organs. They are classified on basis of the types of food they eat. 

• Herbivores: Animals, which eat plants, are called herbivorous animals for e.g. cows, giraffes, goat etc. They have sharp front teeth for biting and strong broad teeth for chewing.
• Carnivores: Animals who eat the flesh of other animals like lions, tiger, cat, vultures etc. They posses sharp pointed and curved teeth for tearing flesh.
• Omnivores: They eat plants as well as flesh of other animals. E.g. crow kites and eagles. They have strong grinding teeth for chewing flesh and bones.

• Mosquitoes suck blood from the body of human beings.
• Snakes swallow their food whole.  
• Elephants have a long trunk. They lift their food with this trunk and put in into their mouths.  
• Birds have beaks and claws.
• Rabbits, rats, squirrel, etc. have sharp front teeth to gnaw seeds and fruits.

So that animals remain healthy, grow and get energy to survive and protect themselves from enemies.
 

c. Breathing Organs

• Gills-- Fishes, tadpoles (baby frog), oysters, prawns and crabs breathe through gills. 
• Lungs-- An adult frog breathes through its lungs on land. Birds, reptiles and mammals also breathe through lungs. 
• Spiracles-- Insects have tiny air holes on their bodies called spiracles to breathe. 
• Body surface-- Small microscopic animals breathe through their body surface like amoeba. 

Animals get oxygen while breathing, which burns the food within their bodies and they get energy to do work.

Now, an activity for you!

• Maintain a notebook.
• Tell your mother to take you to a Zoo, so you can observe the various types of animals.
• Observe at least 5-6 animals there and make a list grouping them - which of them can run, fly, jump, swim, crawl and walk.
• Look at their mouths and try to observe their teeth and see what type of food they take.[Remember, don't go too close to the animals!!]
• Group the animals into plant eaters (herbivores)and flesh eaters(carnivores).
• Find some animals near your house and see what type of houses they make for e.g. burrows, holes or nests.