1 Chapter 30 How Animals Move

2 Introduction Horses are well adapted for long-distance running with legs that are long and light. © 2012 Parson Education, Inc. 2

3 The Vertebrate SkeletonFigure 30.0_1 Chapter 30: Big Ideas Movement and Locomotion The Vertebrate Skeleton Figure 30.0_1 Chapter 30: Big Ideas Muscle Contraction and Movement 3

4 Figure 30.0_2 Figure 30.0_2 A horse at full gallop 4

5 MOVEMENT AND LOCOMOTION© 2012 Parson Education, Inc. 5

6 30.1 Locomotion requires energy to overcome friction and gravityAnimal movement is very diverse but relies on the same cellular mechanisms, moving protein strands against one another using energy. Locomotion is active travel from place to place and requires energy to overcome friction and gravity. Student Misconceptions and Concerns Students may struggle to understand the physics of the mechanisms of movement and the resistant forces that are overcome. Students may not have had a physics course or be able to recall basic principles of force and motion. Consider addressing the fundamental concepts of friction and resistance before addressing examples of terrestrial, aquatic, and aerial locomotion. Teaching Tips 1. Aquatic turtles generally have a more streamlined profile than their terrestrial relatives such as box turtles. 2. Students may not have considered the impact of drag forces on the efficiency of movement through air or water. The tapered trailing end of a boat or automobile may reduce drag and improve efficiency. Rowing a boat with a blunted end reveals the turbulence that trails the craft in the water. This contrasts with the more even flow of water past the tapered rear end of a canoe. The structural advantage of a tapered tail can be observed in the conical end of a jet and that of a fast-moving fish. 3. As a laboratory exercise, challenge students to observe the movements of an earthworm and describe the mechanism outlined in Module Students will require a thorough understanding of the muscle layers, setae, hydrostatic skeleton, and internal compartmentalization of an earthworm’s body before they can offer detailed explanations. 4. Challenge your students to distinguish between flying and gliding. Despite the names of flying squirrels and flying fish, these animals glide. One distinction between gliding and flying is the ability to gain and maintain altitude. © 2012 Parson Education, Inc. 6

7 30.1 Locomotion requires energy to overcome friction and gravityAn animal swimming is supported by water but slowed by friction. Student Misconceptions and Concerns Students may struggle to understand the physics of the mechanisms of movement and the resistant forces that are overcome. Students may not have had a physics course or be able to recall basic principles of force and motion. Consider addressing the fundamental concepts of friction and resistance before addressing examples of terrestrial, aquatic, and aerial locomotion. Teaching Tips 1. Aquatic turtles generally have a more streamlined profile than their terrestrial relatives such as box turtles. 2. Students may not have considered the impact of drag forces on the efficiency of movement through air or water. The tapered trailing end of a boat or automobile may reduce drag and improve efficiency. Rowing a boat with a blunted end reveals the turbulence that trails the craft in the water. This contrasts with the more even flow of water past the tapered rear end of a canoe. The structural advantage of a tapered tail can be observed in the conical end of a jet and that of a fast-moving fish. 3. As a laboratory exercise, challenge students to observe the movements of an earthworm and describe the mechanism outlined in Module Students will require a thorough understanding of the muscle layers, setae, hydrostatic skeleton, and internal compartmentalization of an earthworm’s body before they can offer detailed explanations. 4. Challenge your students to distinguish between flying and gliding. Despite the names of flying squirrels and flying fish, these animals glide. One distinction between gliding and flying is the ability to gain and maintain altitude. © 2012 Parson Education, Inc. 7

8 Figure 30.1A Figure 30.1A A fish swimming 8

9 30.1 Locomotion requires energy to overcome friction and gravityAn animal walking, hopping, or running involves less overall friction between air and the animal, must resist gravity, and requires good balance. Student Misconceptions and Concerns Students may struggle to understand the physics of the mechanisms of movement and the resistant forces that are overcome. Students may not have had a physics course or be able to recall basic principles of force and motion. Consider addressing the fundamental concepts of friction and resistance before addressing examples of terrestrial, aquatic, and aerial locomotion. Teaching Tips 1. Aquatic turtles generally have a more streamlined profile than their terrestrial relatives such as box turtles. 2. Students may not have considered the impact of drag forces on the efficiency of movement through air or water. The tapered trailing end of a boat or automobile may reduce drag and improve efficiency. Rowing a boat with a blunted end reveals the turbulence that trails the craft in the water. This contrasts with the more even flow of water past the tapered rear end of a canoe. The structural advantage of a tapered tail can be observed in the conical end of a jet and that of a fast-moving fish. 3. As a laboratory exercise, challenge students to observe the movements of an earthworm and describe the mechanism outlined in Module Students will require a thorough understanding of the muscle layers, setae, hydrostatic skeleton, and internal compartmentalization of an earthworm’s body before they can offer detailed explanations. 4. Challenge your students to distinguish between flying and gliding. Despite the names of flying squirrels and flying fish, these animals glide. One distinction between gliding and flying is the ability to gain and maintain altitude. © 2012 Parson Education, Inc. 9

10 Figure 30.1B Figure 30.1B A dog running at full speed 10

11 Figure 30.1C Figure 30.1C Kangaroos hopping 11

12 30.1 Locomotion requires energy to overcome friction and gravityAn animal burrowing or crawling must overcome great friction between the animal and the ground, is more stable with respect to gravity, may move by side-to-side undulations (such as snakes), or may move by a form of peristalsis (such as worms). Student Misconceptions and Concerns Students may struggle to understand the physics of the mechanisms of movement and the resistant forces that are overcome. Students may not have had a physics course or be able to recall basic principles of force and motion. Consider addressing the fundamental concepts of friction and resistance before addressing examples of terrestrial, aquatic, and aerial locomotion. Teaching Tips 1. Aquatic turtles generally have a more streamlined profile than their terrestrial relatives such as box turtles. 2. Students may not have considered the impact of drag forces on the efficiency of movement through air or water. The tapered trailing end of a boat or automobile may reduce drag and improve efficiency. Rowing a boat with a blunted end reveals the turbulence that trails the craft in the water. This contrasts with the more even flow of water past the tapered rear end of a canoe. The structural advantage of a tapered tail can be observed in the conical end of a jet and that of a fast-moving fish. 3. As a laboratory exercise, challenge students to observe the movements of an earthworm and describe the mechanism outlined in Module Students will require a thorough understanding of the muscle layers, setae, hydrostatic skeleton, and internal compartmentalization of an earthworm’s body before they can offer detailed explanations. 4. Challenge your students to distinguish between flying and gliding. Despite the names of flying squirrels and flying fish, these animals glide. One distinction between gliding and flying is the ability to gain and maintain altitude. © 2012 Parson Education, Inc. 12

13 Longitudinal muscle relaxed (extended) Circular muscle contractedFigure 30.1D Longitudinal muscle relaxed (extended) Circular muscle contracted Circular muscle relaxed Longitudinal muscle contracted Head 1 Figure 30.1D An earthworm crawling by peristalsis Bristles 2 3 13

14 Longitudinal muscle relaxed (extended) Circular muscle contractedFigure 30.1D_1 Longitudinal muscle relaxed (extended) Circular muscle contracted Circular muscle relaxed Longitudinal muscle contracted Head 1 Bristles Figure 30.1D_1 An earthworm crawling by peristalsis (part 1) 2 3 14

15 Figure 30.1D_2 Figure 30.1D_2 An earthworm crawling by peristalsis (part 2) 15

16 30.1 Locomotion requires energy to overcome friction and gravityAn animal flying uses its wings as airfoils to generate lift. Flying has evolved in very few groups of animals. Flying animals include most insects, reptiles, including birds, and bats (mammals). Student Misconceptions and Concerns Students may struggle to understand the physics of the mechanisms of movement and the resistant forces that are overcome. Students may not have had a physics course or be able to recall basic principles of force and motion. Consider addressing the fundamental concepts of friction and resistance before addressing examples of terrestrial, aquatic, and aerial locomotion. Teaching Tips 1. Aquatic turtles generally have a more streamlined profile than their terrestrial relatives such as box turtles. 2. Students may not have considered the impact of drag forces on the efficiency of movement through air or water. The tapered trailing end of a boat or automobile may reduce drag and improve efficiency. Rowing a boat with a blunted end reveals the turbulence that trails the craft in the water. This contrasts with the more even flow of water past the tapered rear end of a canoe. The structural advantage of a tapered tail can be observed in the conical end of a jet and that of a fast-moving fish. 3. As a laboratory exercise, challenge students to observe the movements of an earthworm and describe the mechanism outlined in Module Students will require a thorough understanding of the muscle layers, setae, hydrostatic skeleton, and internal compartmentalization of an earthworm’s body before they can offer detailed explanations. 4. Challenge your students to distinguish between flying and gliding. Despite the names of flying squirrels and flying fish, these animals glide. One distinction between gliding and flying is the ability to gain and maintain altitude. © 2012 Parson Education, Inc. 16

17 Figure 30.1E Airfoil Figure 30.1E A bald eagle flying 17

18 Figure 30.1E_1 Figure 30.1E_1 A bald eagle flying 18

19 30.1 Locomotion requires energy to overcome friction and gravityAnimal movement results from a collaboration between muscles and a skeletal system to overcome friction and gravity. Student Misconceptions and Concerns Students may struggle to understand the physics of the mechanisms of movement and the resistant forces that are overcome. Students may not have had a physics course or be able to recall basic principles of force and motion. Consider addressing the fundamental concepts of friction and resistance before addressing examples of terrestrial, aquatic, and aerial locomotion. Teaching Tips 1. Aquatic turtles generally have a more streamlined profile than their terrestrial relatives such as box turtles. 2. Students may not have considered the impact of drag forces on the efficiency of movement through air or water. The tapered trailing end of a boat or automobile may reduce drag and improve efficiency. Rowing a boat with a blunted end reveals the turbulence that trails the craft in the water. This contrasts with the more even flow of water past the tapered rear end of a canoe. The structural advantage of a tapered tail can be observed in the conical end of a jet and that of a fast-moving fish. 3. As a laboratory exercise, challenge students to observe the movements of an earthworm and describe the mechanism outlined in Module Students will require a thorough understanding of the muscle layers, setae, hydrostatic skeleton, and internal compartmentalization of an earthworm’s body before they can offer detailed explanations. 4. Challenge your students to distinguish between flying and gliding. Despite the names of flying squirrels and flying fish, these animals glide. One distinction between gliding and flying is the ability to gain and maintain altitude. © 2012 Parson Education, Inc. 19

20 30.2 Skeletons function in support, movement, and protectionSkeletons provide body support, movement by working with muscles, and protection of internal organs. There are three main types of animal skeletons: hydrostatic skeletons, exoskeletons, and endoskeletons. Student Misconceptions and Concerns As noted below, many analogies can be developed to help illustrate the fundamental differences between hydrostatic skeletons, exoskeletons, and endoskeletons. Although students may be able to distinguish between these types of skeletons, appreciating the advantages and disadvantages of each is typically more challenging. Students may need to be reminded why each system is adaptive for the particular organisms in which it is found. Teaching Tips 1. The internal pressure exerted by the water enclosed in a water balloon determines the balloon’s physical shape and properties, much as it does in a hydrostatic skeleton. Internal fluid pressure also helps to increase the stiffness of leaves. 2. Like a suit of armor, an exoskeleton must be rebuilt to permit growth. Similarly, as children grow, we must provide larger clothing to cover the surface of their bodies. 3. An exoskeleton is generally similar to the structure of a piece of M&M candy. The hard outer coating provides firm support and protection for the soft interior. © 2012 Parson Education, Inc. 20

21 30.2 Skeletons function in support, movement, and protection1. Hydrostatic skeletons are fluid held under pressure in a closed body compartment and found in worms and cnidarians. Hydrostatic skeletons help protect other body parts by cushioning them from shocks, give the body shape, and provide support for muscle action. Student Misconceptions and Concerns As noted below, many analogies can be developed to help illustrate the fundamental differences between hydrostatic skeletons, exoskeletons, and endoskeletons. Although students may be able to distinguish between these types of skeletons, appreciating the advantages and disadvantages of each is typically more challenging. Students may need to be reminded why each system is adaptive for the particular organisms in which it is found. Teaching Tips 1. The internal pressure exerted by the water enclosed in a water balloon determines the balloon’s physical shape and properties, much as it does in a hydrostatic skeleton. Internal fluid pressure also helps to increase the stiffness of leaves. 2. Like a suit of armor, an exoskeleton must be rebuilt to permit growth. Similarly, as children grow, we must provide larger clothing to cover the surface of their bodies. 3. An exoskeleton is generally similar to the structure of a piece of M&M candy. The hard outer coating provides firm support and protection for the soft interior. © 2012 Parson Education, Inc. 21

22 Figure 30.2A Figure 30.2A The hydrostatic skeleton of a hydra in two states 22

23 30.2 Skeletons function in support, movement, and protection2. Exoskeletons are rigid external skeletons that consist of chitin and protein in arthropods and calcium carbonate shells in molluscs. Exoskeletons must be shed to permit growth. Student Misconceptions and Concerns As noted below, many analogies can be developed to help illustrate the fundamental differences between hydrostatic skeletons, exoskeletons, and endoskeletons. Although students may be able to distinguish between these types of skeletons, appreciating the advantages and disadvantages of each is typically more challenging. Students may need to be reminded why each system is adaptive for the particular organisms in which it is found. Teaching Tips 1. The internal pressure exerted by the water enclosed in a water balloon determines the balloon’s physical shape and properties, much as it does in a hydrostatic skeleton. Internal fluid pressure also helps to increase the stiffness of leaves. 2. Like a suit of armor, an exoskeleton must be rebuilt to permit growth. Similarly, as children grow, we must provide larger clothing to cover the surface of their bodies. 3. An exoskeleton is generally similar to the structure of a piece of M&M candy. The hard outer coating provides firm support and protection for the soft interior. © 2012 Parson Education, Inc. 23

24 Figure 30.2B Figure 30.2B The exoskeleton of an arthropod: a crab molting 24

25 Shell (exoskeleton) Mantle Figure 30.2CFigure 30.2C The exoskeleton of a mollusc: a cowrie (a marine snail) 25

26 30.2 Skeletons function in support, movement, and protection3. Endoskeletons consist of hard or leathery supporting elements situated among the soft tissues of an animal. They may be made of cartilage or cartilage and bone (vertebrates), spicules (sponges), or hard plates (echinoderms). Student Misconceptions and Concerns As noted below, many analogies can be developed to help illustrate the fundamental differences between hydrostatic skeletons, exoskeletons, and endoskeletons. Although students may be able to distinguish between these types of skeletons, appreciating the advantages and disadvantages of each is typically more challenging. Students may need to be reminded why each system is adaptive for the particular organisms in which it is found. Teaching Tips 1. The internal pressure exerted by the water enclosed in a water balloon determines the balloon’s physical shape and properties, much as it does in a hydrostatic skeleton. Internal fluid pressure also helps to increase the stiffness of leaves. 2. Like a suit of armor, an exoskeleton must be rebuilt to permit growth. Similarly, as children grow, we must provide larger clothing to cover the surface of their bodies. 3. An exoskeleton is generally similar to the structure of a piece of M&M candy. The hard outer coating provides firm support and protection for the soft interior. © 2012 Parson Education, Inc. 26

27 Figure 30.2D Figure 30.2D A living sea urchin (left) and its endoskeleton (right) 27

28 Figure 30.2E Figure 30.2E Bone (tan) and cartilage (blue) in the endoskeleton of a vertebrate: a frog 28

29 Figure 30.2E_1 Figure 30.2E_1 The endoskeleton of a vertebrate: a frog (photo) 29

30 THE VERTEBRATE SKELETON© 2012 Parson Education, Inc. 30

31 30.3 EVOLUTION CONNECTION: Vertebrate skeletons are variations on an ancient themeThe vertebrate skeletal system provided the structural support and means of location that enabled tetrapods to colonize land. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips 1. Students often struggle to distinguish the series of vertebrae forming the vertebral column from the actual nervous tissue of the spinal cord. They may benefit from instructors making a clear distinction between these related structures when the axial skeleton is first introduced. 2. Most vertebrate skulls do much more than house the brain. In most vertebrates, the brain is a relatively small structure housed deep in the skull. A vertebrate skull typically houses all the major sense organs, serves as the site of firm muscle attachments, and is the entry point for the respiratory and digestive systems. 3. The pectoral girdle is attached much more loosely to the axial skeleton than the pelvic girdle, in which the sacral vertebrae are firmly attached to the ilium on each side of the body. Challenge your students to explain why the pectoral and pelvic girdles have such different relationships to the axial skeleton. (The propulsive forces of the rear legs can best drive the body through the direct transfer of forces with a firmly attached pelvic girdle. The more loosely arranged pectoral girdle permits a broader range of motion and flexibility, but at the expense of the efficient transfer of forces.) © 2012 Parson Education, Inc. 31

32 30.3 EVOLUTION CONNECTION: Vertebrate skeletons are variations on an ancient themeThe human skeleton consists of an axial skeleton that supports the axis or trunk of the body and consists of the skull, vertebrae, and ribs and appendicular skeleton that includes the appendages and the bones that anchor the appendage and consists of the arms, legs, shoulders, and pelvic girdles. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips 1. Students often struggle to distinguish the series of vertebrae forming the vertebral column from the actual nervous tissue of the spinal cord. They may benefit from instructors making a clear distinction between these related structures when the axial skeleton is first introduced. 2. Most vertebrate skulls do much more than house the brain. In most vertebrates, the brain is a relatively small structure housed deep in the skull. A vertebrate skull typically houses all the major sense organs, serves as the site of firm muscle attachments, and is the entry point for the respiratory and digestive systems. 3. The pectoral girdle is attached much more loosely to the axial skeleton than the pelvic girdle, in which the sacral vertebrae are firmly attached to the ilium on each side of the body. Challenge your students to explain why the pectoral and pelvic girdles have such different relationships to the axial skeleton. (The propulsive forces of the rear legs can best drive the body through the direct transfer of forces with a firmly attached pelvic girdle. The more loosely arranged pectoral girdle permits a broader range of motion and flexibility, but at the expense of the efficient transfer of forces.) © 2012 Parson Education, Inc. 32

33 Figure 30.3A The human skeletonSkull Clavicle Pectoral girdle Scapula Sternum Ribs Humerus Vertebra Radius Ulna Pelvic girdle Carpals Phalanges Metacarpals Figure 30.3A The human skeleton Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges 33

34 Skull Clavicle Pectoral Sternum girdle Scapula Ribs Humerus VertebraFigure 30.3A_1 Skull Clavicle Pectoral girdle Sternum Scapula Ribs Humerus Vertebra Radius Ulna Figure 30.3A_1 The human skeleton (part 1) Pelvic girdle Carpals Phalanges Metacarpals 34

35 Femur Patella Tibia Fibula Tarsals Metatarsals PhalangesFigure 30.3A_2 Femur Patella Tibia Figure 30.3A_2 The human skeleton (part 2) Fibula Tarsals Metatarsals Phalanges 35

36 7 cervical vertebrae Intervertebral discs 12 thoracic vertebraeFigure 30.3B 7 cervical vertebrae Intervertebral discs 12 thoracic vertebrae 5 lumbar vertebrae Figure 30.3B The human backbone, showing the groups of vertebrae Hip bone Sacrum Coccyx 36

37 30.3 EVOLUTION CONNECTION: Vertebrate skeletons are variations on an ancient themeVertebrate bodies reveal variations of this basic skeletal arrangement. Master control (homeotic) genes are active during early development and direct the arrangement of the skeleton. Vertebrate evolution has included changes in these master control genes. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips 1. Students often struggle to distinguish the series of vertebrae forming the vertebral column from the actual nervous tissue of the spinal cord. They may benefit from instructors making a clear distinction between these related structures when the axial skeleton is first introduced. 2. Most vertebrate skulls do much more than house the brain. In most vertebrates, the brain is a relatively small structure housed deep in the skull. A vertebrate skull typically houses all the major sense organs, serves as the site of firm muscle attachments, and is the entry point for the respiratory and digestive systems. 3. The pectoral girdle is attached much more loosely to the axial skeleton than the pelvic girdle, in which the sacral vertebrae are firmly attached to the ilium on each side of the body. Challenge your students to explain why the pectoral and pelvic girdles have such different relationships to the axial skeleton. (The propulsive forces of the rear legs can best drive the body through the direct transfer of forces with a firmly attached pelvic girdle. The more loosely arranged pectoral girdle permits a broader range of motion and flexibility, but at the expense of the efficient transfer of forces.) © 2012 Parson Education, Inc. 37

38 Python Chicken T h o r a c i Thoracic vertebrae v e r t b a LumbarFigure 30.3C Python Chicken T h o r a c i Thoracic vertebrae v e r t b a Lumbar vertebrae Cervical vertebrae Gene expression during development Figure 30.3C Expression of two Hox genes in a python (left) and a chicken (right) Hoxc6 Hoxc8 Hoxc6 and Hoxc8 38

39 30.4 Bones are complex living organsCartilage at the ends of bones cushions joints and reduces friction of movements. Fibrous connective tissue covering most of the outer surface of bone forms new bone in the event of a fracture. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips 1. Students may have encountered hyaline cartilage at the ends of chicken bones during a meal. If the ends of bones have been exposed during cooking, the cartilage dehydrates and does not appear white and glossy. However, if a joint has been separated after cooking, such as a thigh that has been dislocated from the drumstick of a chicken, the glossiness of the white cartilage, which reduces friction, can be appreciated. 2. People do not often consume the nutritious elements inside of bone (although these tissues provide flavoring in soups that include a soup bone). However, in times and places with limited nutritional resources, boiling bones and/or breaking them open allows access to these additional nutrients. © 2012 Parson Education, Inc. 39

40 30.4 Bones are complex living organsBone cells live in a matrix of flexible protein fibers and hard calcium salts and are kept alive by blood vessels, hormones, and nerves. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips 1. Students may have encountered hyaline cartilage at the ends of chicken bones during a meal. If the ends of bones have been exposed during cooking, the cartilage dehydrates and does not appear white and glossy. However, if a joint has been separated after cooking, such as a thigh that has been dislocated from the drumstick of a chicken, the glossiness of the white cartilage, which reduces friction, can be appreciated. 2. People do not often consume the nutritious elements inside of bone (although these tissues provide flavoring in soups that include a soup bone). However, in times and places with limited nutritional resources, boiling bones and/or breaking them open allows access to these additional nutrients. © 2012 Parson Education, Inc. 40

41 30.4 Bones are complex living organsLong bones have a central cavity storing fatty yellow bone marrow and spongy bone located at the ends of bones containing red bone marrow, a specialized tissue that produces blood cells. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips 1. Students may have encountered hyaline cartilage at the ends of chicken bones during a meal. If the ends of bones have been exposed during cooking, the cartilage dehydrates and does not appear white and glossy. However, if a joint has been separated after cooking, such as a thigh that has been dislocated from the drumstick of a chicken, the glossiness of the white cartilage, which reduces friction, can be appreciated. 2. People do not often consume the nutritious elements inside of bone (although these tissues provide flavoring in soups that include a soup bone). However, in times and places with limited nutritional resources, boiling bones and/or breaking them open allows access to these additional nutrients. © 2012 Parson Education, Inc. 41

42 Cartilage Spongy bone (contains red bone marrow) Compact bone CentralFigure 30.4 Cartilage Spongy bone (contains red bone marrow) Compact bone Central cavity Yellow bone marrow Figure 30.4 The structure of an arm bone Fibrous connective tissue Blood vessels Cartilage 42

43 Cartilage Spongy bone (contains red bone marrow) Compact bone CentralFigure 30.4_1 Cartilage Spongy bone (contains red bone marrow) Figure 30.4_1 The structure of an arm bone (part 1) Compact bone Central cavity 43

44 Yellow bone marrow Fibrous connective tissue Blood vessels CartilageFigure 30.4_2 Yellow bone marrow Fibrous connective tissue Blood vessels Figure 30.4_2 The structure of an arm bone (part 2) Cartilage 44

45 30.5 CONNECTION: Healthy bones resist stress and heal from injuriesBone cells repair bones and reshape bones throughout life. Broken bones are realigned and immobilized and bone cells build new bone, healing the break. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips Astronauts typically suffer from bone loss. After months of time in the microgravity of space, the problem can become significant. Biomedical researchers working with NASA are trying to better understand the causes of bone loss so that they can develop methods to limit it. © 2012 Parson Education, Inc. 45

46 Figure 30.5A Figure 30.5A X-rays of a broken leg (left) and the same leg after the bones were set with a plate and screws (right) 46

47 30.5 CONNECTION: Healthy bones resist stress and heal from injuriesOsteoporosis is a bone disease, characterized by low bone mass and structural deterioration, and less likely if a person has high levels of calcium in the diet, exercises regularly, and does not smoke. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips Astronauts typically suffer from bone loss. After months of time in the microgravity of space, the problem can become significant. Biomedical researchers working with NASA are trying to better understand the causes of bone loss so that they can develop methods to limit it. © 2012 Parson Education, Inc. 47

48 Figure 30.5B Figure 30.5B Healthy spongy bone tissue (left) and bone damaged by osteoporosis (right) 48

49 30.6 Joints permit different types of movementJoints allow limited movement of bones. Different joints permit various movements. Ball-and-socket joints enable rotation in the arms and legs. Hinge joints in the elbows and knees permit movement in a single plane. Pivot joints enable the rotation of the forearm at the elbow. Student Misconceptions and Concerns 1. Students often think of bones as static structures that provide support. The continuous growth of bone is a nonstop sculpting process that allows our bones to accommodate the dynamic effects of mass and motion. 2. General definitions of tissue often fail to include extracellular substances. In endoskeletons and exoskeletons, such substances play vital roles in mineral storage and resisting the dynamic forces of movement. Teaching Tips Consider challenging your students to identify examples of human engineered structures that reflect the properties of the three types of joints described in Module The authors already note the similarity between a hinge joint in our elbow and the hinge of a door. © 2012 Parson Education, Inc. 49

50 Figure 30.6 Three kinds of jointsHead of humerus Humerus Scapula Ulna Ulna Radius Ball-and-socket joint Hinge joint Pivot joint Figure 30.6 Three kinds of joints 50

51 Ball-and-socket jointFigure 30.6_1 Head of humerus Scapula Figure 30.6_1 Three kinds of joints: ball-and-socket joint (part 1) Ball-and-socket joint 51

52 Humerus Ulna Hinge joint Figure 30.6_2Figure 30.6_2 Three kinds of joints: hinge joint (part 2) Hinge joint 52

53 Ulna Radius Pivot joint Figure 30.6_3Figure 30.6_3 Three kinds of joints: pivot joint (part 3) Pivot joint 53

54 MUSCLE CONTRACTION AND MOVEMENT© 2012 Parson Education, Inc. 54

55 30.7 The skeleton and muscles interact in movementMuscles and bones interact to produce movement. Muscles are connected to bones by tendons and can only contract, requiring an antagonistic muscle to reverse the action and relengthen muscles. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. Muscle cells are only able to contract. None can actively relengthen. Challenge your students to explain how muscle cells return to their extended length. (Answer: Opposing muscles or other forces, such as gravity, act in opposition to relengthen muscle cells when they relax.) Teaching Tips The structure of a tendon is very similar to that of a steel cable. In a tendon, collagen fibers are neatly arranged and slightly twisted together. Steel wire in a cable has a similar design. The twist in both structures permits a limited amount of stretch to prevent the tendon or cable from snapping when a strong force is suddenly applied. © 2012 Parson Education, Inc. 55

56 Biceps contracted, triceps relaxed (extended) Triceps contracted,Figure 30.7A Biceps contracted, triceps relaxed (extended) Triceps contracted, biceps relaxed Biceps Biceps Figure 30.7A Antagonistic action of muscles to pull bones up or down in the human arm Triceps Triceps Tendons 56

57 30.8 Each muscle cell has its own contractile apparatusMuscle fibers are cells that consist of bundles of myofibrils. Skeletal muscle cells are cylindrical, have many nuclei, and are oriented parallel to each other. Myofibrils contain overlapping thick filaments composed primarily of the protein myosin and thin filaments composed primarily of the protein actin. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. The actual mechanism of skeletal muscle contraction, the bending of myosin heads, is not well understood by most students. Consider focusing on this fundamental question as an introduction, exploring the answer as the detail of muscle structure is explored. Teaching Tips Students might wonder why skeletal muscle cells have many nuclei. One of the limits of cell size is the ability of a nucleus to control the cytoplasm. As the cytoplasmic volume increases, additional nuclei have been adaptive. A general analogy is that of a day-care center. At some point, as additional children are accepted into the center, more supervisors are required. There is a limit to the number of children that can be responsibly supervised by a single person, just as there is a limit to the amount of cytoplasm that can be controlled by one nucleus. © 2012 Parson Education, Inc. 57

58 30.8 Each muscle cell has its own contractile apparatusSarcomeres are repeating groups of overlapping thick and thin filaments and the contractile unit—the fundamental unit of muscle action. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. The actual mechanism of skeletal muscle contraction, the bending of myosin heads, is not well understood by most students. Consider focusing on this fundamental question as an introduction, exploring the answer as the detail of muscle structure is explored. Teaching Tips Students might wonder why skeletal muscle cells have many nuclei. One of the limits of cell size is the ability of a nucleus to control the cytoplasm. As the cytoplasmic volume increases, additional nuclei have been adaptive. A general analogy is that of a day-care center. At some point, as additional children are accepted into the center, more supervisors are required. There is a limit to the number of children that can be responsibly supervised by a single person, just as there is a limit to the amount of cytoplasm that can be controlled by one nucleus. © 2012 Parson Education, Inc. 58

59 Figure 30.8 The contractile apparatus of skeletal muscleSeveral muscle fibers Single muscle fiber (cell) Nuclei Plasma membrane Myofibril Light band Dark band Light band Z line Figure 30.8 The contractile apparatus of skeletal muscle Sarcomere Thick filaments (myosin) Thin filaments (actin) Z line Z line Sarcomere 59

60 Muscle Several muscle fibers Single muscle fiber (cell) Figure 30.8_1Figure 30.8_1 The contractile apparatus of skeletal muscle (part 1) Single muscle fiber (cell) 60

61 Single muscle fiber (cell) Nuclei Plasma membrane Myofibril Light bandFigure 30.8_2 Single muscle fiber (cell) Nuclei Plasma membrane Myofibril Light band Dark band Light band Z line Figure 30.8_2 The contractile apparatus of skeletal muscle (part 2) Sarcomere 61

62 Light band Dark band Light band Z line Sarcomere Thick filamentsFigure 30.8_3 Light band Dark band Light band Z line Sarcomere Thick filaments (myosin) Figure 30.8_3 The contractile apparatus of skeletal muscle (part 3) Thin filaments (actin) Z line Z line Sarcomere 62

63 Figure 30.8_4 Figure 30.8_4 The contractile apparatus of skeletal muscle (part 4) 63

64 30.9 A muscle contracts when thin filaments slide along thick filamentsAccording to the sliding-filament model of muscle contraction, a sarcomere contracts (shortens) when its thin filaments slide across its thick filaments. Contraction shortens the sarcomere without changing the lengths of the thick and thin filaments. When the muscle is fully contracted, the thin filaments overlap in the middle of the sarcomere. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. The actual mechanism of skeletal muscle contraction, the bending of myosin heads, is not well understood by most students. Consider focusing on this fundamental question as an introduction, exploring the answer as the detail of muscle structure is explored. Teaching Tips Students might need help understanding how the contraction of sarcomeres over microscopic distances results in the perceptible motions of our body. Consider explaining it like this: Imagine we have a train with 100 cars that are all 20 feet long. If we shorten each car by 1 foot, how much shorter will the train be? (100 feet.) The collective contraction of sarcomeres adds up to much larger movements. © 2012 Parson Education, Inc. 64

65 Sarcomere Dark band Z Z Relaxed muscle Contracting muscleFigure 30.9A Sarcomere Dark band Z Z Relaxed muscle Contracting muscle Figure 30.9A The sliding-filament model of muscle contraction Fully contracted muscle Contracted sarcomere 65

66 30.9 A muscle contracts when thin filaments slide along thick filamentsMyosin heads of the thick filaments bind ATP and extend to high-energy states. Myosin heads then attach to binding sites on the actin molecules and pull the thin filaments toward the center of the sarcomere. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. The actual mechanism of skeletal muscle contraction, the bending of myosin heads, is not well understood by most students. Consider focusing on this fundamental question as an introduction, exploring the answer as the detail of muscle structure is explored. Teaching Tips Students might need help understanding how the contraction of sarcomeres over microscopic distances results in the perceptible motions of our body. Consider explaining it like this: Imagine we have a train with 100 cars that are all 20 feet long. If we shorten each car by 1 foot, how much shorter will the train be? (100 feet.) The collective contraction of sarcomeres adds up to much larger movements. © 2012 Parson Education, Inc. 66

67 Figure 30.9B The mechanism of filament slidingThick filament Thin filaments Z line Actin 1 Thin filament ATP Myosin head (low- energy configuration) Thick filament 2 ADP Myosin head (high- energy configuration) P 3 ADP P Cross-bridge ADP P  New position of Z line Figure 30.9B The mechanism of filament sliding Thin filament moves toward center of sarcomere. 4 Myosin head (pivoting to low-energy configuration) 5 ATP Myosin head (low- energy configuration) 67

68 Thick filament Thin filaments Z line Figure 30.9B_s1Figure 30.9B_s1 The mechanism of filament sliding (part 1, step 1) 68

69 energy configuration)Figure 30.9B_s2 Thick filament Thin filaments Z line Actin 1 Thin filament ATP Myosin head (low- energy configuration) Thick filament Figure 30.9B_s2 The mechanism of filament sliding (part 1, step 2) 69

70 energy configuration)Figure 30.9B_s3 Thick filament Thin filaments Z line Actin 1 Thin filament ATP Myosin head (low- energy configuration) Thick filament Figure 30.9B_s3 The mechanism of filament sliding (part 1, step 3) 2 ADP Myosin head (high- energy configuration) P 70

71 Cross-bridge 3 ADP P Figure 30.9B_s4Figure 30.9B_s4 The mechanism of filament sliding (part 2, step 1) 71

72 Cross-bridge New position of Z line Thin filament moves toward center.Figure 30.9B_s5 3 ADP P Cross-bridge New position of Z line ADP P  Thin filament moves toward center. 4 Myosin head (pivoting) Figure 30.9B_s5 The mechanism of filament sliding (part 2, step 2) 72

73 Cross-bridge New position of Z line Thin filament moves toward center.Figure 30.9B_s6 3 ADP P Cross-bridge New position of Z line ADP P  Thin filament moves toward center. 4 Myosin head (pivoting) Figure 30.9B_s6 The mechanism of filament sliding (part 2, step 3) 5 Myosin head (low-energy) ATP 73

74 30.10 Motor neurons stimulate muscle contractionA motor neuron carries an action potential to a muscle cell, releases the neurotransmitter acetylcholine from its synaptic terminal, and initiates a muscle contraction. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. Students often fail to realize that aerobic metabolism is a process generally similar to the burning of wood or the burning of gasoline in an automobile engine. Noting these general similarities can help students better comprehend both the overall reaction and the heat generation associated with these processes. Teaching Tips One way to help explain motor units is to provide an analogy with the controls for the sets of lights in your classroom (if you are so equipped). Each set of lights is controlled by its own switch. The lights in one set all turn on or off (or perhaps dim) together. The total amount of light in the room depends upon how many sets of lights are turned on. Just as in muscles, if a room requires more refined lighting, more switches (more motor units) will control fewer lights each (fewer muscle cells per motor unit). © 2012 Parson Education, Inc. 74

75 Mitochondrion Motor neuron axon Action potential Synaptic terminalFigure 30.10A Mitochondrion Motor neuron axon Action potential Synaptic terminal T tubule Endoplasmic reticulum (ER) Figure 30.10A How a motor neuron stimulates muscle contraction Ca2 released from ER Myofibril Plasma membrane Sarcomere 75

76 30.10 Motor neurons stimulate muscle contractionAn action potential in a muscle cell passes along T tubules and into the center of the muscle fiber. Calcium ions are released from the endoplasmic reticulum and initiate muscle contraction by moving the regulatory protein tropomyosin away from the myosin-binding sites on actin. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. Students often fail to realize that aerobic metabolism is a process generally similar to the burning of wood or the burning of gasoline in an automobile engine. Noting these general similarities can help students better comprehend both the overall reaction and the heat generation associated with these processes. Teaching Tips One way to help explain motor units is to provide an analogy with the controls for the sets of lights in your classroom (if you are so equipped). Each set of lights is controlled by its own switch. The lights in one set all turn on or off (or perhaps dim) together. The total amount of light in the room depends upon how many sets of lights are turned on. Just as in muscles, if a room requires more refined lighting, more switches (more motor units) will control fewer lights each (fewer muscle cells per motor unit). © 2012 Parson Education, Inc. 76

77 Myosin-binding sites blockedFigure 30.10B Myosin-binding sites blocked Tropomyosin Ca2-binding sites Actin Troponin complex Ca2 floods the cytoplasmic fluid Figure 30.10B Thin filament, showing the interactions among actin, regulatory proteins, and Ca2+ Myosin-binding sites exposed Myosin-binding site 77

78 30.10 Motor neurons stimulate muscle contractionA motor unit consists of a neuron and the set of muscle fibers it controls. More forceful muscle contractions result when additional motor units are activated. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. Students often fail to realize that aerobic metabolism is a process generally similar to the burning of wood or the burning of gasoline in an automobile engine. Noting these general similarities can help students better comprehend both the overall reaction and the heat generation associated with these processes. Teaching Tips One way to help explain motor units is to provide an analogy with the controls for the sets of lights in your classroom (if you are so equipped). Each set of lights is controlled by its own switch. The lights in one set all turn on or off (or perhaps dim) together. The total amount of light in the room depends upon how many sets of lights are turned on. Just as in muscles, if a room requires more refined lighting, more switches (more motor units) will control fewer lights each (fewer muscle cells per motor unit). © 2012 Parson Education, Inc. 78

79 Spinal cord Motor unit 1 Motor unit 2 Nerve Motor neuron cell bodyFigure 30.10C Spinal cord Motor unit 1 Motor unit 2 Nerve Motor neuron cell body Motor neuron axon Synaptic terminals Nuclei Muscle fibers (cells) Muscle Figure 30.10C Motor units Tendon Bone 79

80 30.11 CONNECTION: Aerobic respiration supplies most of the energy for exerciserequires a constant supply of glucose and oxygen and provides most of the ATP used to power muscle movement during exercise. The anaerobic process of lactic acid fermentation can provide ATP faster than aerobic respiration but is less efficient. Student Misconceptions and Concerns 1. As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). 2. Students often fail to realize that aerobic metabolism is a process generally similar to the burning of wood or the burning of gasoline in an automobile engine. Noting these general similarities can help students better comprehend both the overall reaction and the heat generation associated with these processes. Teaching Tips During cellular respiration, our cells convert about 40% of our food energy to useful work. The other 60% of the energy is released as heat. We use this heat to maintain a relatively steady body temperature near 37°C (98–99°F). This is about the same amount of heat generated by a 75-watt incandescent light bulb. When we exercise our muscles, we need more ATP. The extra production of ATP results in an excess production of heat. Thus, we generally produce too much heat when we exercise, and have evolved various mechanisms to dissipate this heat into our environment (such as sweating and increasing blood flow to the surface of our body). © 2012 Parson Education, Inc. 80

81 Figure 30.11 Figure Running, a good form of aerobic exercise 81

82 Table 30.11 Table Sources of ATP for athletic activities 82

83 30.12 CONNECTION: Characteristics of muscle fiber affect athletic performanceDepending on the pathway they use to generate ATP, muscle fibers can be classified as slow, intermediate, or fast. Most muscles have a combination of fiber types, which can be affected by exercise. Student Misconceptions and Concerns As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). Teaching Tips 1. As noted in Module 30.12, exercise stimulates the production of additional myofibrils. Thus, muscle growth is primarily a consequence of an increase in cell size due to the addition of myofibrils. (Additional mitochondria and blood vessels also contribute to the increase in muscle mass). 2. The differences between dark meat and white meat in birds such as chickens reflect differences in types of skeletal muscle fibers. Unlike humans, these birds have muscles made up primarily of just one type of muscle fiber. Dark meat contains higher amounts of myoglobin, fat, and capillaries, which are associated with sustained exertion. White meat, with less fat, less myoglobin, and fewer capillaries, is associated with quick bursts of energy, such as the contractions of the pectoral muscles to generate lift during takeoff. Artificial selection has resulted in variations on these basic differences. © 2012 Parson Education, Inc. 83

84 Table 30.12 Table Characteristics of muscle fibers 84

85 30.12 CONNECTION: Characteristics of muscle fiber affect athletic performanceMuscles can adapt to exercise by increasing the levels of myoglobin, number of mitochondria, and/or number of capillaries going to muscles. Student Misconceptions and Concerns As the generation of ATP is discussed, students should be cautioned against the idea that “energy is created” when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics, addressed in Module 5.10). Teaching Tips 1. As noted in Module 30.12, exercise stimulates the production of additional myofibrils. Thus, muscle growth is primarily a consequence of an increase in cell size due to the addition of myofibrils. (Additional mitochondria and blood vessels also contribute to the increase in muscle mass). 2. The differences between dark meat and white meat in birds such as chickens reflect differences in types of skeletal muscle fibers. Unlike humans, these birds have muscles made up primarily of just one type of muscle fiber. Dark meat contains higher amounts of myoglobin, fat, and capillaries, which are associated with sustained exertion. White meat, with less fat, less myoglobin, and fewer capillaries, is associated with quick bursts of energy, such as the contractions of the pectoral muscles to generate lift during takeoff. Artificial selection has resulted in variations on these basic differences. © 2012 Parson Education, Inc. 85

86 Percentage of total muscleFigure 30.12 100 Slow 80 Intermediate Fast 60 Percentage of total muscle 40 20 Figure Percentage of slow, intermediate, and fast muscle fibers in quadriceps (thigh) muscles of different individuals World- class sprinter Average couch potato Average active person Middle- distance runner World- class marathon runner Extreme endurance athlete 86

87 You should now be able toDescribe the diverse methods of locomotion found among animals and the forces each method must overcome. Describe the three main types of skeletons, their advantages and disadvantages, and provide examples of each. Describe the common features of terrestrial vertebrate skeletons, distinguishing between the axial and appendicular skeletons. © 2012 Parson Education, Inc. 87

88 You should now be able toDescribe the complex structure of bone, noting the major tissues and their relationship to blood-forming tissues. Explain why bones break and how we can help them heal. Describe three types of joints and provide examples of each. Explain how muscles and the skeleton interact to produce movement. © 2012 Parson Education, Inc. 88

89 You should now be able toExplain at the cellular level how a muscle cell contracts. Explain how a motor neuron signals a muscle fiber to contract. Describe the role of calcium in a muscle contraction. Explain how motor units control muscle contraction. Explain what causes muscle fatigue. © 2012 Parson Education, Inc. 89

90 You should now be able toDistinguish between aerobic and anaerobic exercise, noting the advantages of each. Compare the structure and functions of slow, intermediate, and fast muscle fibers. © 2012 Parson Education, Inc. 90

91 Figure 30.UN01 Figure 30.UN01 Reviewing the Concepts, 30.1 91

92 Sarcomere Myosin Actin Figure 30.UN02Figure 30.UN02 Reviewing the Concepts, 30.9 92

93 Animal movement must overcome forces of requires both gravityFigure 30.UN03 Animal movement must overcome forces of requires both gravity and friction (a) (b) types are move parts of usually in hydrostatic skeleton units of contraction are antagonistic pairs (c) (d) Figure 30.UN03 Connecting the Concepts, question 1 shorten as myosin pulls actin filaments endoskeleton made of called sliding-filament model (e) 93