The Animal World
Concept: Locomotion in Animals
What is locomotion?
Locomotion is defined as the ability of an organism to move from one place to another.
Features of locomotion:
- The skeletal system in the human body helps in locomotion.
- Different types of bones and muscles take part in the locomotory action.
- The mode of locomotion varies from one animal to another depending on their structural makeup and habitats.
Need for locomotion:
- Animals move from one place to another for the following reasons—
- In search of shelter.
- In search of food.
- For reproduction.
- For escaping from predators.
Locomotion in earthworm:
- Earthworms are invertebrates, and they lack bones. Their body is made of segmented rings.
- Locomotion of earthworms depends on their muscular actions.
- Continuous expansion and contraction of muscles help them move.
- The body of an earthworm secretes a slimy substance that also helps them move and keep their body moist.
- Earthworms possess tiny hair-like structures called bristles under their body that allow them to get a grip on the ground.
Locomotion in snail:
- Snails are invertebrates, and they have a characteristic shell on their back. The shell plays no role in the locomotion of a snail; rather, it has to be dragged along.
- Snails have a thick muscular structure at the base, which is considered their feet.
- The surface below the muscular foot is covered with mucus that helps in locomotion and decreases the body’s risk of injury from sharp objects.
- Snails propel themselves using their muscular feet by generating waves of muscular contractions along the surface.
Locomotion in cockroach:
- Cockroaches are invertebrates having a hard outer skeleton, called exoskeleton, covering their bodies.
- They have a body structure that enables them to walk, climb and fly in the air.
- Cockroaches have three pairs of legs and two pairs of wings attached to their feet.
- There are specific muscles in a cockroach’s body for walking and flying.
- Cockroaches have spines on their legs that help them move in different landscapes.
Locomotion in birds:
- Birds are vertebrates, and their streamlined body makes it easier for them to fly.
- The bones of birds are hollow that make their bodies light.
- Strong muscles attached to the breast bones help in flight.
- Their forelimbs are modified into wings, whereas the hind limb bones are modified to walk and perch.
- Birds have strong shoulder bones, and their tails help control the direction of flight.
Locomotion in fishes:
- Fishes are vertebrates. They are aquatic organisms adapted to live in water.
- Their streamlined body is covered with scales, and this unique body shape help them move in the water.
- The skeleton of fish has strong muscles that contract and relax to make a jerk-like movement.
- A series of these jerk-like movements causes the fish to swim ahead.
- The limbs are modified to form fins that help in swimming.
- The different fins help in keeping the body balance and maintaining directions.
- The tail helps the fish move in the right direction.
Locomotion in snakes:
- Snakes are vertebrates.
- They do not move in a straight line; rather, they move in S-shaped loops in a zigzag manner.
- Snakes slither against the ground with the help of their long backbone and thin muscles attached to it.
- The loop-like movement allows the snake to make a forward push against the surface.
Other modes of locomotion:
Some other modes of locomotion seen in animals are—
- Running: Tiger, lion, deer, cheetah.
- Hopping: Rabbit, Hare
- Gliding: Flying squirrel
Adaptations in animals for locomotion:
- Presence of webbed feet
- Presence of a membrane between hindlimbs and forelimbs:
Webbed feet in some animals enables them to swim very well, such as frogs, ducks, swans and penguins.
An additional membrane present between the hindlimb and forelimb in flying squirrels enables them to glide when they open their limbs.
Hindlimbs and Forelimbs: Hindlimbs are limbs present at the lower end of the body, i.e., legs, whereas limbs present at the upper end of the body, i.e., hands, are called forelimbs.
Vertebrates and Invertebrates: Animals with a backbone are called vertebrates, and animals without a backbone are called invertebrates.
Mucus:A slippery substance released by certain animals for locomotion and keeping their body moist.
Streamlined: A body shape that tapers at both ends.
Did You Know?
- A hippopotamus runs faster than a man.
- A grasshopper can jump 40 times the length of their bodies.
- Caterpillar has 4000 muscles, whereas a human has around 630 muscles.