Animal Life – Reproduction in Animals
You must have seen sometime, bird feeding their babies or
dog playing with their puppies or monkey hugging its baby. Do you wonder at the
similarity between animals and their babies? We observe that animal and their
babies have same characteristic and features. Both animal and their young ones
have same pattern of hair, skin, tail etc.
do animals have babies similar to them?
All living thing reproduce to replace their old and
dying forms. If they do not reproduce their form will disappear from the earth.
Example: If cat does not reproduce, they will not be seen in future after some
time. So, reproduction is vital process for every animal to continue its race.
Reproduction is a process by which living organism
produce another one of their own kind.
do animals reproduce?
Two main ways of reproduction
- By laying eggs
- By giving birth to young ones
That Lay Eggs
Some animals reproduce by laying eggs. These include
insects, fish, frogs, snakes, lizards, snails, birds and crocodiles.
Bird builds nest to lay eggs. Birds nurture their eggs
to keep them at the proper temperature, before these eggs hatch into young
All eggs are protected by hard covering made of calcium
carbonate called the shell. Shell is porous that allows the transfer of
gases through the shell. Within the shell are the albumen (white) and the yolk
(yellow). Albumen contains protein that is necessary for development of
growing bird and Yolk is the source of food, contains the fat. The young
bird will only develop at the proper temperature, this happens only when bird
sits on them for several days.
When the baby bird hatches from the egg, they do not
have feathers. So, the bird feeds their young ones till their feather develops.
Most of the insects such as butterflies, grasshoppers,
cockroaches and houseflies lay eggs. The young ones when come out of eggs look
very different from their parent. During their growth, they keep shedding their
outer layer or covering of their body and gradually develop into adult. This
process of shedding off outer covering of the body i.e. skin by the baby insect
during their growth is called Moulting.
Small baby cockroach or grasshopper that hatches from
egg is called nymph. They do resemble their parent but lack wings. After
shedding their skin several times, they turn into adult.
Butterfly and housefly eggs when hatches, small worms
come out called larva. The larva of butterfly is called caterpillar and
larva of housefly is called maggot.
Cycle of Butterfly
Butterfly lay eggs on leaf and tiny worm like structure
hatch from the egg called larva (caterpillar). Caterpillar eats leaves
all the time and becomes plump and sluggish. When it cannot eat more, it covers
itself from the thread that comes out of the caterpillar’s body. This stage is
called pupa. The caterpillar undergoes many changes inside the cocoon. This
change occurring in the form, structure, or function of organism in the process
of its growth or development is called metamorphosis. After few weeks
later, a beautiful butterfly comes out of cocoon.
Cycle of Frog
Frogs lay eggs in water or wet place. Eggs hatches into
small tadpoles. These tadpoles look more like a fish rather a frog. Tadpole has
no legs but has a long tail and breathes through gills in water. They feed on
pond weeds and gradually turns into froglets and then into frog. An adult frog
breathes through lungs.
Lizards, turtle and snakes also lay eggs but do not
give any parental care. Most of their laid eggs are eaten by other animals. Among
reptiles only crocodiles and their relatives tend both eggs and babies. Crocodiles
make nest in the ground and lay eggs there. They carry their babies to the
water body after the egg hatches and took care of them for some time.
that give birth to young ones
Some animal give birth to young ones. Such animal are
called mammals. This includes animals such as dogs, cats, monkeys, tigers, cows,
elephants, horses and humans. The baby develops inside the mother’s body. After
their birth they feed on mother’s milk till they learn to feed by their own.
Whales and dolphins lives in water but they give birth
to young ones. Bat though a bird give birth to young ones.