BIOLOGY FORM THREE TOPIC 2: MOVEMENT

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MOVEMEN

Concept of Movement and Locomotion
Movement refers to change of position and posture. Therefore the change of position of body parts such as limbs and other body parts.
Locomotion is the movement or change of position of the whole organism from one place to another.
But normally organisms have different kinds of movement. Plants show movement but do not show locomotion.
Since locomotion involves coordination between nervous muscular and skeletal system and all these system enable the organism to locomote.
Ankit Yadav: Chapter 20

The Importance of Movement in Animals and Plants

Animals and plants move about to:
  1. Find a mate and to reproduce
  2. Escape danger
  3. Seek and capture food
  4. To seek shelter, a suitable habitat/climate
  5. To avoid competition for food/water, living space etc
  6. Find water/soil nutrients, and hold leaves to get maximum sunlight
  7. Seek and capture food
  8. Obtain support
  9. Protect themselves from damage from: touch/pressure, pain or sudden temperature change
  10. Disperse seeds

Movement and Locomotion Actions

Demonstration of movement and locomotion
Movement action
Movement action
Locomotion action
Locomotion action
Explain the concept of movement in plants (movement of curvature)
Generally plants do not show locomotion (movement of the entire organism). However, movement of individual plant organs is possible and modified by sensitivity of the plant to external stimuli.
Plant movements in response to internal stimuli are known as spontaneous movement. Examples of these movements are metabolic conditions, disease conditions, vex ages and parental influence Those movements shown by plants in response to external stimuli are known as induced or irritablemovements.
Plant Life: Nastic Movements
Types of Movement Exhibited by Plants
Normally there are two types of plant movements, which are:
  1. Spontaneous movement
  2. Induced (irritable) movement
Spontaneous Movement is plant movement in response to internal stimuli. Example of these movements are metabolic conditions, disease conditions, vex ages and parental influences
Induced or Irritable Movement is the type of plant movement shown by plants in response to external stimuli. Light, temperature, gravity, touch, water and chemical substances are examples of induced movement.
Induced movements include nastic movement, tactic movement and tropic movement.

A summary of the types of movements shown by plants in response to stimuli.
STIMULI
  • Light
  • Chemicals
  • Water
  • Temperature
  • Contact
  • Gravity
  • Gravitactic or Gravitaxis
Tropic Movements in Plants
Tropic movements are the growth movements shown by a fixed part of a stationary plant towards or away from a stimulus coming from one direction. Tropic movements are also known as tropism movements.
Tropic (tropism) is growth movements, which take place at a very slow pace. The growth movement is caused by an increased or decreased rate of growth on the side of the organ, which is under the influence of the stimulus, with respect to the opposite side. This results in growth in curvature.
There are various types of tropic movements, these types are:
  • Phototropism or phototropic which is a growth movement shown by part of a fixed plant in response to light
  • Hydrotropism (Hydrotropic) which is growth movement in a response to water
  • Thigmotropism (Thigmotropic) which is the growth movement in response to touch
  • Chemotropism (Chemotropic) which is a growth movement made by plants towards chemicals
  • Thermotropism (Thermotropic), a growth movement shown in plants in response to heat.
Experiments to Investigate Movement in Plants
Carry out experiments to investigate movement in plants
An experiment to investigate movement in plants

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