1. http://www.clipconverter.cc/download/EjciIwL6/60427923/
http://www.edunation.my/form-5-biology/
http://es.thefreedictionary.com/escap%c3%a9
Form 5: Chapter 2 – Locomotion and Support 2.1 Support and Locomotion in Humans and
Animals
Locomotion in an animal with an endoskeleton (fish)1. Why can a fish swim in a viscous and
dense environment:a) body wight is supported by water to overcome gravity. b) sleek and
streamlined body to overcome resistance.c) overlapping scales on the body of a fish face
backwards to overcome resistance.d) covered by slimy coating to minimize frictional drag and
maintains a smooth flow of water.2. Vertebral column of the fish is moved from side to side
by the contraction andrelaxation of myotomes.
Prepared by: Mr. Gerard Selvaraj
12

3. Form 5: Chapter 2 – Locomotion and Support 2.1 Support and Locomotion in Humans and
Animals
3. Myotomes – W shaped muscle blocks that make up each side of the body of a fish andcarry
out opposite action.4. Alternating waves of contraction and relaxation pass down the
myotomes on either side of the body from the head to the tail.5. These cause different parts of
the body to be swept from side to side pushing water backwards and sideways and the body
forwards.6. Tendency for a fish to become unstable in water during movement, leading to:-a)
yawing – sideways movement b) pitching – vertical plane movementc) rolling – transverse
plane movement7. Movements are countered by fins. Caudal fin provides thrust and controls
the fish’sdirection.8. These movements are countered by:-a) yawing – resisted by the median
(dorsal and ventral) fin b) rolling – resisted by median finc) Pitching – resisted by paired

4. pelvic fin and pectoral fin which acts as brakes andrudders.9. Bony fish have swim bladders
to help them maintain buoyancy in the water.10. The swim bladder is a sac inside the
abdomen that contains gas.11. Controlling the amount of gas in the swim bladder, a fish can
change its buoyancy sothat it has the same relative density as the surrounding water.
Prepared by: Mr. Gerard Selvaraj
13