Without the ability to move, there would be no life on Earth. Moving around is
essential to many animals for finding food and a mate. Even plants move, by
spreading themselves with the help of seeds or sprouts. But how is moving around
possible? What kinds of adaptations
do different kinds of animals in different environments have, and how do they help
them survive? Lets take a look at that.
Movement in Earthworm :
An earthworm move by contracting its muscles to shorten its body, then extending
the body to reach further. When an earthworm contracts its body, it holds shortened
portion or base to the ground with small bristles. These bristles anchor the worm,
allowing it to not slip backward when contracting and allowing it to stretch.
Earthworms are also covered in mucus, which helps their movement through soil.
Earthworms are highly beneficial to the soil as their movement mixes the dirt they
travel through. Worms also aid in the breakdown of organic matter such as
vegetation by consuming it. Earthworms tend to feed on leaves, plants and even clay
and chalk. Earthworm movement also creates open paths in the dirt, which allow for
water flow and water removal.
Movement in Snail :
The snail has an unusual body sticking out from the underside of its coiled shell.
This body is actually a strong muscle called a foot. A snail’s foot is made up of
many tiny muscles which help it to crawl about in an up-and-down, or wavelike,
motion. The waves start at the front of the snail’s foot and move backwards. As the
waves pass through the muscles from one end of the foot to the other, the snail
Snails can creep on the ground or on the ocean floor, climb walls and trees, and
even hang upside down. This is because as the snail moves, a sticky fluid, called
mucus, flows out from tiny glands in front of the foot. The mucus acts as a track
or roadway, allowing the snail to stick to surfaces, even while hanging upside
down. This mucus also protects the snail from rough or sharp surfaces. A snail can
actually glide right over the sharp edge of a knife or razor blade without getting
Snails can creep completely into their shell and even seal themselves in with a
“door” of their dried mucus!
Movement in Fish :
Fish swim by propelling themselves through the water in a wave-like fashion. Fish
with streamlined bodies and crescent-shaped caudel fins move faster through the
water by moving their tail from side to side - this moves them forward a lot like
rowing a boat with an oar.
Fish also use their pectoral fins, which are situated horizontally on the body of
fish who are fast swimmers. In combination with the pelvic fins, these help to
stabilize the fish to keep it from rolling over as it moves through the water.
The pectoral fins are set almost vertically in slower swimming fish. These with the
pelvic fins help the fish by acting as brakes. They can also assist the fish with
difficult maneuvers. Take an hour to just watch your fish swimming and you will
understand how they swim and why and you will start to see which kinds of aquariums
are more conducive to a better and healthier way of life for your fish. In general,
because of the way fish are put together (their anatomy) you can see that they
generally swim horizontally. This is why a longer, rectangular aquarium is best to
allow them to swim and maneuver freely.
Movement in Birds :
Birds are adapted to moving in the air. Their front limbs have turned into wings
and their strong pectoral muscles move their feathered wings. Bird bones are hollow
inside so that the bodyweight is as small as possible, which makes it easier for
them to fly.
Wing movement provides lift as well as the propulsion needed to overcome "drag" and
to gain speed. The bird's wing movement might be compared to a swimmer's doing the
"butterfly stroke." His arms rotate around his shoulder joint, as he throws them
forward through the air and then pulls them back through the water. Flight,
however, is far more complex, involving the rotation of the wing and the relative
movements of various parts of it.
The faster the bird travels, the more lift will come from the air passing around
the wings. It has been calculated that a pigeon first taking off uses five times as
much energy as when it reaches steady flight.
With most larger birds, the increased wingspan is still not large enough to cope
with their extra weight and greater drag, especially when taking off. So some of
these, such as the pelican, run on the ground for a few feet to gain speed for
lift. Others, such as the vultures, land on a tree or fence and then, by jumping
off, gain enough speed through the pull of gravity for their wings to provide lift.
The heaviest bird that can fly is the trumpeter swan, weighing up to 40 pounds (18
kilograms). Heavy birds are limited in the amount of flapping they can do because
of the strenuous effort involved. However, this does not restrict their ability to
fly, for they are masters of another form of flight.
Movement in Snakes :
Snakes have four ways of moving around. Since they don't have legs they use their
muscles and their scales to do the "walking".
- Serpentine method: This motion is what most people think of when they think of
snakes. Snakes will push off of any bump or other surface, rocks, trees, etc., to
get going. They move in a wavy motion. They would not be able to move over slick
surfaces like glass at all. This movement is also known as lateral undulation.
- Concertina method: This is a more difficult way for the snake to move but is
effective in tight spaces. The snake braces the back portion of their body while
pushing and extending the front portion. Then the snake drops the front portion of
their body and straightens an pulls the back portion along. It is almost like they
through themselves forward.
- Sidewinding: This is a difficult motion to describe but it is often used by
snakes to move on loose or slippery surfaces like sand or mud. The snake appears
to throw its head forward and the rest of its body follows while the head is thrown
forward again. (See picture.)
- Rectilinear Method: This is a slow, creeping, straight movement. The snake uses
some of the wide scales on its belly to grip the ground while pushing forward with
Movement in Human Beings :
The skeleton is the inner framework of BONES that supports and gives shape to the
human body. It also protects some of the soft organs of the body—for example, the
skull surrounds the brain. Muscles and ligaments pull on the bones of the skeleton
at JOINTS to make the body move.
Weight for weight, bone is five times stronger than steel, but it is very light.
The skeleton makes up only one-sixth of an adult’s weight. The skull, in
particular, is very strong, because it has to protect the brain and sense organs,
such as the eyes, ears, and nose.
This strong yet flexible material is a living tissue, made up of bone cells
embedded in a matrix of fibers. Bone is not solid—blood vessels and nerves run
through tunnels within it, and some areas are a honeycomb of small spaces. In the
center of many bones is a cavity packed with a jellylike substance called bone
WHAT IS BONE MADE OF?
The hard matrix of bone is made of crystals of calcium phosphate and other
minerals, and fibers of protein called collagen. The minerals make bone hard, while
the collagen fibers are arranged lengthwise to make bone flexible. Both are
produced by cells called osteocytes, found throughout the matrix.
Bones connect at joints. Different types of joint allow different movements. Joints
are often held together by straps of tough fibrous tissue, called ligaments, and
the muscles that cross the joint. The four major movable joints in our body are :
1. Hinge Joints
The human skeleton's range of movements depends on its joints--literally where
bones join with each other. One of the more obvious of such joints is the hinge
joint, of which is expressed every time we flex our elbows or knees.
2. Ball and Socket
There are four primary ball and socket joints in the human body, at both shoulders
and both hips. They allow the widest range of motion in the human body, offering
lateral, vertical and rotational movement across a much wider range than any other
3. Glide Joints
Glide joints allow the sliding of bone over each other. These are primarily found
in the hands and feet of the skeleton, and while are limited in range of motion,
offer overall flexibility across a surface.
4. Pivot Joint
Pivot joints allow rotation along an axis, such as that which is utilized by our
skull and spine. The two bones of the forearm also utilize a pivoting motion, but
rotate around each other.
- Overall Movement
The simplest actions, such as picking up an apple and bringing it to your mouth, is
actually a complex orchestra of multiple joints working in tandem. Even grasping
the apple utilizes the full range of hinge and gliding joints found in your hand.
Student of Class 6
National Public School Indore 452005