CHAPTER 30 How Animals Move

1. CHAPTER 30How Animals Move

2. How Do Ants Move Forests? • A colony of leaf-cutter ants can strip a large tree of its foliage in a single night • Adults feed on the sap from the trees • Young ants eat fungi that grow on the leaves

3. Here other workers chew the leaves to cultivate a particular species of fungus for food • Over a period of 4-5 years, a colony of leaf-cutters may excavate 50 tons of forest soil (to make nests) and process many tons of forest leaves • Ants carry the leaves to their subterranean nest

4. an exoskeleton made of chitin • three pairs of jointed legs • The ant body is a model of strength and mobility made possible by Exoskeletalpiece Joints

5. The nervous system issues commands to the muscular system • The muscular system exerts propulsive force against the skeleton • Movement is one of the most distinctive features of animals

6. MOVEMENT AND LOCOMOTION 30.1 Diverse means of animal locomotion have evolved • Some aquatic animals do not move • Instead they move body parts to generate currents that bring them food • Example: sponges

7. It requires use of energy to overcome forces of friction and gravity • The relative importance of friction and gravity varies depending on the environment • Locomotion is active travel from place to place

8. Gravity has little effect on aquatic animals • But friction slows them down • A streamlined body shape is an adaptation that aids rapid swimming • Swimming Figure 30.1A

9. Using limbs as oars • Expelling water for jet propulsion • Moving tail from side to side • Moving body up and down • There are several methods of swimming

10. Gravity has a great effect on land animals • But friction has little effect • Animals must be able to support themselves against the force of gravity • They must also maintain balance • Movement on land

11. Legs stabilize the body and propel the animal forward • Muscles generate power for movement • Springy legs store energy for each step or jump • Hopping, walking, running, and crawling are methods of movement on land Figure 30.1B, C

12. There are two methods of crawling • Side-to-side undulation • Peristalsis (head-to-tail waves of muscle contraction) • Animals that crawl must overcome friction

13. Longitudinalmusclerelaxed(extended) Circular musclecontracted Circular musclerelaxed Longitudinalmusclecontracted • An earthworm crawls by peristalsis Head 1 Bristles 2 3 Figure 30.1D

14. Birds, bats, some insects, and extinct reptiles • Flying is the locomotion method of only a few animal groups

15. Lift is generated by the airfoil structure of the wing • Wings must develop enough lift to completely overcome the downward pull of gravity Airfoil Figure 30.1E

16. SKELETAL SUPPORT 30.2 Skeletons function in support, movement, and protection • Skeletons have three major functions • Support • Movement • Protection of internal organs

17. Hydrostatic skeleton • Exoskeleton • Endoskeleton • There are three main types of skeletons

18. Consists of fluid held under pressure in a closed body compartment • Protects body parts by cushioning them from shock • Provides body shape, which can be changed by contracting muscles in the body wall • Provides support for muscle action • Earthworms, hydras, and jellies have hydrostatic skeletons • Hydrostatic skeleton

19. The hydrostatic skeleton of a hydra Figure 30.2A

20. Rigid external skeleton • It can be hard or leathery • Exoskeleton

21. The shells of mollusks are exoskeletons made of calcium carbonate • The exoskeleton of arthropods is made of chitin Shell (exoskeleton) Mantle Figure 30.2B, C

22. Consists of hard or leathery supporting elements situated among the soft tissues • Most echinoderms, including sea stars and sea urchins, have an endoskeleton of hard plates beneath their skin • Endoskeleton Figure 30.2D

23. Vertebrate endoskeletons consist of cartilage or a combination of cartilage and bone Figure 30.2E

24. 30.3 The human skeleton is a unique variation on an ancient theme • All vertebrates have an axial skeleton • Supports the axis, or trunk, of the body • Consists of the skull, backbone, and, in most vertebrates, a rib cage • Most vertebrates also have an appendicular skeleton • Supports the paired appendages • Consists of bones of the shoulder girdle, upper limbs, pelvic girdle, and lower limbs in humans

25. Figure 30.3A

26. Three kinds are found in the vertebrate skeleton • Movable joints provide flexibility Head ofhumerus Humerus Scapula Ulna Ulna Radius 1 2 3 Ball-and-socket joint Hinge joint Pivot joint Figure 30.3C

27. The human skeleton changed dramatically as upright posture and bipedalism evolved Human Baboon Figure 30.3B

28. 30.4 Connection: Skeletal disorders afflict millions • The human skeleton is versatile, but it is also subject to problems • Lower-back pain • Arthritis • Osteoporosis

29. 30.5 Bones are complex living organs • Bones consist of several kinds of living tissues • A sheet of fibrous connective tissue covers bones • Cartilage at the end of bones cushions joints • Bone tissues are served by blood vessels and nerves

30. Cartilage Spongybone(contains redbone marrow) • A human humerus Compact bone Central cavity Yellowbone marrow Fibrousconnectivetissue Bloodvessels Cartilage Figure 30.5

31. Protein fibers resist cracking • Calcium salts resist compression • Long bones • A central cavity contains the yellow marrow that stores fat • Spongy bone contains the red marrow that produces blood cells • Bone cells live in a matrix of flexible protein fibers and hard calcium salts

32. 30.6 Connection: Broken bones can heal themselves • Bones are rigid but not inflexible • If a force is applied that exceeds a bone's capacity, a fracture will result • Two factors determine whether a bone will break • The strength of the skeleton • The amount of energy applied to the skeleton

33. The first step is realigning the bone • Sometimes traction must be used to align the broken parts • The treatment of broken bones involves two steps

34. The second step is to immobilize the bone • Splint or cast • Plates, rods, and/or screws • Bone cells then build new bone and repair the break Figure 30.6A

35. Several materials can be used in this treatment • Titanium or cobalt alloys • Bone grafts • Synthetic polymers • Severely injured or diseased bone is beyond repair and must be replaced Figure 30.6B

36. MUSCLE CONTRACTION AND MOVEMENT 30.7 The skeleton and muscles interact in movement • Muscles pull on bones, which act as levers that produce movement • Tendons connect muscles to bone • Antagonistic pairs of muscles produce opposite movements

37. Biceps contracted,triceps relaxed(extended) Tricepscontracted,biceps relaxed Biceps Biceps Triceps Triceps Tendon Figure 30.7

38. A muscle is returned to an extended position by being pulled by other parts of the skeleton • Muscles perform work only when contracting

39. 30.8 Each muscle cell has its own contractile apparatus • Skeletal muscle • Attached to the skeleton • Provides body movements • Made up of a hierarchy of smaller and smaller parallel strands

40. Figure 30.8

41. 30.9 A muscle contracts when thin filaments slide across thick filaments Sarcomere Dark band Z Z • Sliding-filament model Relaxedmuscle • Explains the molecular process of muscle contraction Contractingmuscle Fully contractedmuscle Figure 30.9A

42. Thick filament (myosin) Z line Thin filament(actin) Myosinhead ATP binds to myosin head, which is releasedfrom an actin filament. 1 Hydrolysis of ATP cocks the myosin head. 2 The myosin head attaches to an actin bindingsite. 3 The power stroke slides the actin (thin)filament toward the center of the sarcomere. 4 Figure 30.9B

43. 30.10 Motor neurons stimulate muscle contraction • Motor neurons carry action potentials that initiate muscle contraction • A motor unit consists of a neuron and all the muscle fibers it controls • The strength of a muscle contraction depends on the number of motor units activated

44. Motorunit 1 Motorunit 2 Spinal cord Nerve Motor neuroncell body Motor neuronaxon Neuromuscularjunctions Nuclei Muscle fibers(cells) Muscle Tendon Bone Figure 30.10A

45. A neuron releases the neurotransmitter acetycholine • Acetycholine triggers an action potential in the muscle fiber • Calcium is released from the endoplasmic reticulum • Calcium then initiates muscle contraction • Activation of the motor units occurs across neuromuscular junctions

46. Motor neuronaxon Action potential Mitochondrion Tubule Endoplasmicreticulum (ER) Myofibril Ca2+ releasedfrom ER Plasma membrane Sarcomere Figure 30.10B

47. 30.11 Connection: Athletic training increases strength and endurance • A balance of aerobic and anaerobic exercise increases strength and endurance Figure 30.11

48. 30.12 The structure-function theme underlies all the parts and activities of an animal • Body movement is a visible reminder that function emerges from structure • An animal's nervous system connects sensations derived from environmental stimuli to responses carried out by its muscles Figure 30.12A, B