Chapter 2

1. Chapter 2 Locomotion and Support

2. 2.1 Support and Locomotion in Humans and Animals

3. 2.1 Support and Locomotion in Humans and Animals • Importance of support and locomotion • Search for food • Provide protection by escaping from enemies or avoiding danger • Search for more conducive living environment • Find mates for reproduction • Avoid overcrowding which enables the offspring to move to another place

4. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Human skeletal system • Consist of two main part; axial skeleton and appendicular skeleton

5. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Skull • Cranium – enclose and protect the brain • Facial bones and jaw • Protect the eyes and ears • Upper jaw is fixed • Skull is joined to the vertebral column at the base of cranium

6. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Rib • Twelve pairs of ribs • Articulate with thoracic cavity dorsally, and sternum ventrally • Sternum is the front part

7. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Vertebral column • Consists of 33 vertebrae, joined but separated by discs of cartilage • Five types of vertebrae • Cervical vertebrae (7) • Thoracic vertebrae (12) • Lumbar vertebrae (5) • Sacral vertebrae (5) • Coccyx

8. 2.1 Support and Locomotion in Humans and Animals (cont’d) Neural arch Forms neural canal Neural spine Muscle attachment Centrum Gives support Neural canal Protects spinal cord

9. 2.1 Support and Locomotion in Humans and Animals (cont’d)

10. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Support head and neck • Sentrum is short and thick • Large and thick sentrum

11. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Appendicular skeleton • Consists of • Pectoral girdles and forelimbs (arms) • Pelvic girdle and hind limbs (legs)

12. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Arms

13. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Legs Pelvic girdle

14. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Joints • Place where two bones meet • Bones are held together by ligaments • Sinovial joints – joints that contains a cavity filled with fluid • End of bones are covered with cartilage.

15. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Joints • Various types of joints • Hinge joint • Allow movement in one plane • Ball-and-socket joint • Allow movement in all directions

16. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Movement in a limb • Skeletal muscles are attached to bones by tendons. • Movements of cause by antagonistic movement of muscles: • One muscles is contracted, another is relaxed

17. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Structure of a muscle • Muscle fibre– single, long cylindrical cell that contains many nuclei • Myofibrils – smaller units that made up muscle fiber • Interaction of actin and myosin will cause muscle contraction

18. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of earthworm • Earthworms have a hydrostatic skeleton (the force of contraction is applied to a coelum(fluid filled chamber). • Coelom is surrounded by two antagonistic muscle • circular muscles – surround the chamber • longitudinal muscles – extend from one end to the other. • Thinner and longer: When circular muscle contract and the longitudinal muscle relax. (and vice verca) • The muscles contract rhythmically to produce peristaltic waves which begins at the front and move towards the end of the body. • Earthworm has chaetae (bristles) which anchor parts of the body to the ground so that other parts can be pulled towards it.

19. 2.1 Support and Locomotion in Humans and Animals (cont’d)

20. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of grasshopper • The flexor and extensor (antagonistic) muscles are attached to the internal surface of the exoskeleton. • Flexor muscles bend a joint. • Extensor muscles straighten it. • The rear legs of a grasshopper are long and muscular and is adapted for hopping. • Sitting position: When the flexor muscle contracts, the lower leg is pulled towards the body. The hind leg is folded in a Z shape and ready for a jump. • Jump: When the extensor muscle contracts, the leg jerks backwards, propelling the grasshopper forward and upward into the air.

21. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of grasshopper

22. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of grasshopper • The flexor and extensor (antagonistic) muscles are attached to the internal surface of the exoskeleton. • Flexor muscles bend a joint. • Extensor muscles straighten it. • The rear legs of a grasshopper are long and muscular and is adapted for hopping. • Sitting position: When the flexor muscle contracts, the lower leg is pulled towards the body. The hind leg is folded in a Z shape and ready for a jump. • Jump: When the extensor muscle contracts, the leg jerks backwards, propelling the grasshopper forward and upward into the air.

23. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of fish • Fish has streamlined body shape • Scales that overlap one another, with free ends pointing backwards to reduce friction • Fish have W-shaped muscles called myotome

24. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of fish • Fish move forward from the contraction and relaxation (antagonistic) of myotome on either side of the body

25. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of fish • Function of fins in fish – balance the body • Pectoral fins – for steering • Pelvic fins – for balance, to prevent diving and rolling

26. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of bird • Bird can fly either by flapping their wings or gliding

27. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of bird • When wings move down • Pectoralis major contracts • Wings are pulled down • When wings move up • Pectoralis minor contracts

28. 2.1 Support and Locomotion in Humans and Animals (cont’d) • Locomotion of bird • During gliding, wings are spread – act as aerofoil • Bernoulli principle – provide upward thrust

29. 2.3 Support SYSTEM IN PLANTS

30. 2.3 Support Systems in Plants • Support in plants is necessary to: • Stay upright • Obtain sufficient sunlight • Bear the weight the plant • Provide strength to withstand wind ressistance

31. 2.3 Support Systems in Plants (cont’d)

32. 2.3 Support Systems in Plants (cont’d) • Submerged plants • Hydrillasp. • Have thin, narrow and flexible leaves – provide little ressistance • Air sacs inside the leaves and stems - keep the plant floating close to the surface to obtain maximum sunlight.

33. 2.3 Support Systems in Plants (cont’d) • Floating plants • Lotus plant • Have broad leaves that are firm but flexible enough to resist tearing by wave action. • Aerenchyma tissues (spongy tissues with large air spaces between the cells) in the stems and leaves provide buoyancy so that the plants can float on the surface of the water

34. 2.3 Support Systems in Plants (cont’d) • Herbaceous plant • Support provided by the turgidity of the parenchyma and collenchyma cells. • Turgor pressure of the fluid content in the central vacuole pushes the cell membrane and the cell contents against the cell wall, creating support for the stem, root and leaves. • The thickening of the cell walls with cellulose and pectin in collenchyma cells provide additional mechanical strength

35. 2.3 Support Systems in Plants (cont’d) • Woody plants • Support provided through tissue modification • Xylem tissues • Strenghtened by lignin • Lignin – tough, not elastic and nor permeable to water • Parenchyma tissues • Store starch, sugars and water • It become turgid – give support

36. 2.3 Support Systems in Plants (cont’d) • Woody plants • Collenchyma tissues • Thickened with cellulose and pectin • Sclerechyma tissues • Thickened with lignin