|
PinkMonkey Online Study Guide-Biology
CHAPTER 21 : LOCOMOTION
21.0 Introduction
Movement is one of the most functional characteristics
of animals. In most animals, movement or locomotion is brought about
by special fibrils or muscular tissues. The basic components
consist of the external body covering the supporting framework (skeleton)
and the skeletal muscles, and provide the means for locomotion.
These components also protect and support internal structures and
provide body shape and form. Locomotion may occur in the form of
walking, running, flying etc. This helps the animal to capture food,
escape from predators, find its mate for reproduction, and many
such activities which help in its survival.
The process of locomotion takes place on certain
physical principles such as density, forces (thrust or pull), machines
(levers in animal bodies), friction, buoyancy (upthrust in air or
water) and stability which is important in a body at rest or in
motion.
In most terrestrial mammals, the hindlimbs provide
the pushing force or thrust which moves the body forward
by foot pressure against the ground. The foot remains in contact
with the ground by friction. The hindlimb produces a power stroke
through straightening of the limb by contraction of extensor muscles,
and a recovery stroke by bending the limb with flexor muscles.
[next page]
|
Table of Contents
21.0 Introduction
21.1 Joints - Articulations between bones
21.2 Muscle movements
Chapter 22
|
