Class VI
Science
Changes Around Us

Types of animals
• Based on the absence or presence of
backbone , animals can be divided
1. Animals with Backbone (Vertebrates )
2. Animals without Backbone (Invertebrates)

Invertebrates
• Animals that do not have a backbone are
called invertebrates.
– Examples are insects like spider and scorpion,
Worms, and slug and snail.
• Insects have six legs and their body is divided
into three parts: head, thorax, and abdomen.
• Most insects have a hard outer covering made
up of a material called chitin.

Vertebrates
• Vertebrates can be divided into
1. Fish
2. Amphibians
3. Reptiles
4. Birds
5. Mammals
• Fish, amphibians, and reptiles are cold-blooded animals. This
means that their body temperature changes with the change
in the temperature of the surrounding
• Warm blooded animals : Animals that have same temperature
inside the body all the time.
– Birds and mammals are warm-blooded animals

Vertebrates
1. Fish
– Live in water
– Breathe through gills
– Have fins to swim
– Body is covered by scale
– Are cold-blooded animals
• Examples : cod,shark,mackerel

Vertebrates
2. Amphibians
– Lives both on land and water
– Breathe both through lungs and moist skin
– Are cold-blooded animals
• Example : Frog, toad, newt

Vertebrates
3. Reptiles
– Live mainly on land.
– Have scaly skins and reproduce by laying eggs.
are reptiles.
– Are cold-blooded animals
• Examples : Lizard, snake, and crocodile

Vertebrates
4. Birds
– Birds have a light body.
– They are covered with feathers.
– They have wings that help them to fly.
– Are warm-blooded animals
• Examples : Crow, sparrow, eagle, etc.
– Birds like ostrich, kiwi, and penguin cannot fly because
they have a heavy body. They are called flightless
birds.
• Hummingbird is the smallest bird in the world.

Vertebrates
5. Mammals
– Animals that give birth to babies (except the
platypus and anteater).
– Their bodies have hair and the mothers suckle
their young ones.
– They breathe through lungs and have four limbs.
– Are warm-blooded animals.,
• Examples : Human, elephant, horse, cow, dog.

Group of animals based place they live
Based on where animals live ,they are grouped
• Terrestrial Animals
– Live on land
• Aquatic animals
– Live in water
• Amphibians
– Live on both on land and in water
• Arboreal animals
– Lives mostly on tree
• Aerial animals
– Fly and spend a lot of time in the air

Terrestrial Animals
• Animals that live on land are called terrestrial
animals.
• These animals have features suitable for life
on land.
• They have legs which help them to walk on
land, and most of them have lungs as their
breathing organ.

Terrestrial Animals
Animals have adapted to live in different climatic
conditions.
• Freezing condition :Animals have a thick layer
of fat called blubber under their skin to keep
their body warm.
• Example: Seal, penguin, and Walrus are
adapted to live in freezing conditions
Seal Penguin
Walrus

Terrestrial Animals
• Cold Places: Animals that live in very cold
places have thick fur on their body, which
protects them from cold.
• Example: It is cold on the mountains and in
the polar regions. A yak lives in the mountains
and a polar bear lives in polar region.
Yak Polar bear

Terrestrial Animals
• Desert: Animals living in deserts have very
little hair on their body. These animals have
certain adaptations that prevent water loss
from their bodies.

Terrestrial Animals
• Hibernation :Animals like bear, frog, and snake
become inactive in cold winter months, since the
food is also scarce. This inactivity during winter
months or winter sleep is called hibernation
• Aestivation :Slowing down of activity or settling
down to along sleep by some animals during the hot
summer months.

Aquatic Animals
• Animals that live in water are called aquatic
animals.
• Most aquatic animals breathe through gills,
except whales and dolphins, which breathe
through lungs.
• Most aquatic animals have fins or paddles that
help them to swim.
• Example : Fish, octopus, turtle, and crab
Turtle Octopus Crab

Amphibians
• Animals that live both on land and in water.
• The back legs of a frog and toad are stronger than
their front legs. This helps them to jump, which is
how they move on land.
• They have webbed feet that help them to swim in
water.
• Example : Toad, Frog

Arboreal animals
• Land animals that live mostly on trees are called
arboreal animals.
• They have sharp claws to climb up and down the
branches and usually have strong, muscular limbs
and a tail for holding on to the branches.
• Example : Monkey and koala bear.
Koala bear

Aerial animals
• Animals that can fly and spend a lot of their time in the air are
called aerial animals.
• Their hollow bones make their bodies light.
• They have one set of limbs modified as wings to help them fly.
• The body shape of aerial animals is such that they able to cut
through the air easily.
• In the cold winter months, when the food become scarce
many birds fly towards warmer countries in search of food
and warmth. This mass movement of birds from a colder to a
warmer place is called migration
• Example : Almost all birds, except flightless birds, Bats

Animal Group based on food they eat.
• Based on the type of food animals eat, they can be
divided into five main groups
1. Herbivores : Animals that eat plants
2. Carnivores : Animals that eat the flesh of other
animals
3. Omnivores :Animals that eat plants as well as the
flesh of other animals
4. Scavengers : Flesh eating animals that feed on the
flesh of dead animals
5. Parasites : Some small animals get their food from
other living organisms

Herbivores.
• Animals that eat plants are called
herbivores.
• They have sharp teeth for biting and cutting,
and very strong teeth for grinding as plant
food needs to be chewed a lot as it is very rich
in a substance called cellulose.
• Example :Horse, Cow

Carnivores
• Animals that eat the flesh of other
animals are called Carnivores.
• Most carnivorous animals have very
sharp teeth for tearing out the flesh of its
prey.
• Example :Lion, tiger, snake, and lizard

Omnivores, Scavengers
• Animals that eat plants as well as the flesh of
other animals are called Omnivores
– Example :Crow ,bear and Human beings
• Scavengers are some flesh-eating animals feed
on the flesh of dead animals.
– Example :Vulture, hyena

Parasites
• Some small animals get their food from other
living organisms.
• They get their food by sucking the blood of
their host.
• They may live on or inside the body of their
host.
• Example : Fleas and lice live on the host body ,
tapeworm, roundworm and hook worm live
inside the host’s body

Adaptations for protection
• Many animals have adapted themselves to the environment
and to protect themselves from their enemies.
1. Animals like elephant and hippopotamus have thick skin to
protect themselves from the hot climate.
2. Some animals have very strong legs and are able to run
very fast and can easily run away from danger. For
example, deer and gazelle
3. Some animals like chameleon, zebra, arctic fox, polar bear,
and frog can trick their enemies because their body colour
easily blends with their surroundings, thus confusing their
enemies. This is known as camouflaging.
4. A chameleon can also change its body colour according to
the surroundings. Grasshopper and the stick insect are
other examples of animals that show perfect camouflage.

Extinct and Endangered animals
• Some animals like the Dodo has already
disappeared from the Earth. Such animals are
called extinct animals
• Animals like the Giant Panda and tiger are in
danger of becoming extinct. Such animals are
called endangered animals.