Kerala SSLC Class 9 Solutions for biology – Movement and Locomotion (English Medium)
Page No. 46:
What are the benefits of movement to organisms?
Benefits of movement to organisms:
- Helps in gathering food
- Helps to catch prey
- Helps to protect oneself from predators
What are the activities that people are involved in?
People are involved in the following activities:
- Sowing seeds
- Planting saplings
- Cutting logs of wood
- Carrying goods
- Drawing water from a well
- Playing cricket
Find out other examples for voluntary movements.
Examples of voluntary movements:
- Driving car
- Waving of hand
Page No. 47:
Find out examples for involuntary movements.
Examples of involuntary movements:
- Blinking of eye
- Reflexive knee jerk
- Peristaltic movement of oesophagus
- Contraction of the pupil of eyes according to the intensity of light
Examine the following figure and identify some of our voluntary muscles.
Voluntary muscles in our body:
- Muscles of hands
- Muscles of legs
- Muscles in the shoulders
- Muscles of the back
- Muscles in the waist
- Muscles in the neck
How are voluntary movements effected?
Voluntary movements are effected by the contraction and relaxation of voluntary muscles of a particular part of the body.
Observe the figure and find out how movement of the hand is made possible.
- Which muscle is contracting when the hand folds?
- Which muscle is relaxing when the hand folds?
- Which muscle contracts during the stretching of hand?
- Which muscle relaxes when the hand straightens?
- Draw muscles in figure c on the basis of your inferences.
- When the hand folds, the flexor muscle contracts.
- When the hand folds, the extensor muscle relaxes.
- During stretching of the hand, the extensor muscle contracts.
- When the hand straightens, the flexor muscle relaxes.
Page No. 48:
Where are involuntary muscles seen?
Involuntary muscles are seen in tubular structures such as
- Alimentary canal
- Urinary tract
- Blood vessels
What are their (involuntary muscles) characteristics?
Characteristics of involuntary muscles:
- Muscle fibres are spindle shaped.
- The fibres lack striations.
- They do not get tired.
Figures of different types of muscles are given below. Identify the muscles and fill up the table.
Page No. 49:
Are the muscles alone involved in making movement possible?
Movement is possible because of co-ordination in muscles and bones.
Observe the figure. Identify the bones that belong to the axial skeleton and the appendicular skeleton and fill up the table given below.
Page No. 50:
What types of movable joints are available in our body? Where are these joints found?
Movable joints present in our body and their location:
Move the parts of your body, identify the type of joints involved and fill up the table.
Name the part that connects bones to each other?
Ligaments connect the bones to each other.
What is the function of the capsule?
A capsule covers and protects the joints.
How is friction between the bones avoided at the joints?
Synovial fluid secreted by the synovial membrane of the joint acts as a lubricant and avoids friction between the bones at the joints.
Identify the immovable joints of the skull from the figure.
The bones of the skull are joined at the sutures. These are seen as curvy lines on the skull. They are immovable joints present in the skull.
Page No. 51:
Where else in the body do you find cartilage?
Cartilage is found:
- Between joints
- Bronchial tubes
- Intervertebral discs
The skeletal system has many other functions besides helping in movement. Do you know what they are?
Besides helping in movement, the skeletal system has the following functions:
- Provides framework to the body
- Provides structure to the body
- Provides protection to soft tissues and other vital organs of the body
- Stores minerals and releases them in the blood as required
- Helps in the formation of blood cells
Prepare a list of animals with exoskeleton.
Animals which have an exoskeleton:
Are remnants of exoskeleton seen in vertebrates?
Some vertebrates show the presence of an exoskeleton.
For example, crocodiles have horny scales and turtles have an exoskeleton.
Some fish and mammals also show the presence of exoskeleton-like structures. For example, nails, hair, toes and horns are considered parts of the exoskeleton.
Have you thought of the difference between movement and locomotion?
Movement is a change in position of a part of the body. Locomotion is the displacement of the entire body from one place to another.
Page No. 52:
How does the shape of the fish help in its locomotion in water?
Fish have a streamlined body with tapering ends. Pointed ends help fish to tear the course of water as well as reduce friction.
Which are the features in the body of fish that help in movement?
Following features in the body of fish help in its movement:
- Presence of air bladder
- Streamlined body
- Presence of fins
How are fins useful to fish?
Fins are useful to fish in the following ways:
- Fins maintain the balance of the body
- Fins regulate the direction of movement
Page No. 55:
There are plenty of other examples of movements in plants. Find out and list them.
Examples of movement in plants:
- Closing of Venus fly trap to capture its prey
- Dispersal of seeds
- Dispersal of pollen grains
- Movement of the stem towards the direction of sunlight
- Movement of roots towards the direction of water and minerals
- Growth of pollen tube
- Opening and closing of stomata
- Opening and closing of flowers
- Growth of tendrils on the external support
- How does the experimental setup differ from the control setup?
- In which direction has the stem bent in the experimental setup?
- What could be the reason for this?
- What type of phototropism did the stem in the experiment show?
- In the control set up, the plant can receive light from all directions. On the other hand, in the experimental set up, light can enter only through one circular hole created in the wooden box.
- In the experimental set up, the stem bends towards the circular hole from where light enters.
- In the experimental set up, light can enter only through the circular hole created in the box. Thus, the stem of the plant responds to the stimulus of light and grows in the direction of light.
- The stem in the experimental set up showed positive phototropism.
You would have seen that a plant in a pot that has fallen bends to grow upward. Is the influence of light the only reason for this?
The stem of the plant exhibits positive phototropism and negative geotropism. Thus, the plant in a pot which has fallen bends to grow upwards, towards the direction of light and opposite to the direction of gravity.
In the figure, what would be the direction of roots of the plant?
The direction of the roots of the plant in a pot which has fallen is downwards towards gravity.
Page No. 56:
Observe the figures given below.
- In what manner did gravity influence the movements shown by the plant in figure a? Which plant part showed positive geotropism?
- Which part of the plant exhibited negative geotropism?
- Why are such movements not shown by the plant in figure b?
- Under the influence of gravity, the roots of the plant grow downwards and the stem of the plant grows upwards.The roots of the plant thus show positive geotropism.
- The stem of the plant exhibits negative geotropism.
- The set up b was a rotating set up. Thus, the stimuli of light and gravity are acting on all sides of the plant, thus balancing the growth in all directions. Hence, such movements are not shown by the plant in figure b.
Page No. 57:
Movements which are stimulated by touch are called haptotropism. Find out examples and note them down.
Examples of haptotropism:
- Twining of stem around a support
- Clinging roots which hold a support
- Twining of petioles
- Hooks of a stem which attach to a support
- Aerial roots holding a support
Find more examples of nastic movements and note them down.
Examples of nastic movements in plants:
- Leaves and leaflet becoming vertical at night
- Closing of Venus fly trap and Drosera on perched prey
- Blooming of buds
- Dispersal of seeds
- Opening and closing of flowers of tulip