Animal Movement Chapter 30

Locomotion Active travel from place to place Requires energy expenditures to over come 2 forces Friction Gravity Importance depends on the environment

Types of Locomotion Swimming Locomotion on land Gravity not a problem, but friction is Water supports weight, but is dense and presents resistance Legs as oars, jet-propelled, and undulating side to side or up and down Streamlined body shapes aids increased speed Locomotion on land Need to be able to support self and overcome gravity Air presents little resistance, but also little support Energy expenditure to propel forward and keep from falling down Muscles and skeleton more important that streamline shape

Types of Locomotion (cont.) Hopping Tendons in legs store energy when landing, like a spring for the next jump Cost free energy boost Rest with tail and hind feet on ground Costs little energy to maintain Walking and running Overcome friction between foot and ground Walking: 4 legged – 3 on ground all times; 2 legged – part of 1 at all times Running: 4 legged – 2 -3 feet move at once if not all Momentum stabilizes body position

Types of Locomotion (cont.) Crawling Friction adds considerable resistance because of increased contact Undulate body side to side, inch forward, or peristalsis Flying Wings developed to completely overcome gravity Shape must alter air current to create lift Air pressure underneath is greater All based on mircotubule or microfilament systems. Animals in motion Leading edge thicker, lagging edge thinner; top convex, bottom concave or flat

Skeletons 3 main types Hydrostatic skeletons Exoskeletons Endoskeletons Necessary for support, protection, and maintaining form

Hydrostatic Skeleton Fluid held under pressure in a closed body compartment Cushions body parts from shock, gives shape, and support for muscle action Earthworms have coelum Cnidarians exert pressure on gastrovascular cavity Can’t support terrestrial locomotion which requires the body to be held off ground

Exoskeletons Rigid external skeleton Arthropods are protein and chitin Thinner at joints to allow movement Nonliving, so can’t grow must be shed Animal is susceptible to predation and weak until new exoskeleton hardens Molluscs shells of calcium carbonate Mantle secretes shell Grows by enlarging diameter

Endoskeleton Hard or leathery supporting elements among the soft tissues Sponges with tough protein fibers Echinoderms have under their skin Vertebrates of cartilage or cartilage and bone

The Evolved Skeleton All vertebrates have an axial skeleton Supports axis or trunk of the body Skull, vertebrae, and rib cage Vertebrae all similar in structure Cervical, thoracic, lumbar, and sacral, and coccygeal Most have appendicular skeleton Bones of appendages and anchoring appendages Pelvic and pectoral girdle with supporting limbs Modified versions of same bones in all vertebrates, but specialized for locomotion

Bones Organs composed of moist, living tissues Pink=fibrous connetctive, forms new bone after fractures Blue=cartilage, forms cushion- like surface for joints Inside are osteocytes that secrete bone matrix Yellow bone marrow is stored fat from blood to bone Red bone marrow produces RBC’s

Creating Movement Tendons connect muscles to bones Muscle action shortens or contracts muscles The agonist moves the muscle while the antagonist reverses the movement Antagonistic pairs of muscles are found in all animals

Dissecting Muscles Muscles consist of bundles of muscle fibers (cells), oriented parallel to each other Cells are bundles of myofibrils, which are composed of the contractile proteins actin (thin) and myosin (thick) Proteins form a striped banding pattern that characterizes skeletal muscles Contractile unit of skeletal muscle is the sarcomere

Contracting Filament Model Sarcomere contracts when thin filaments slide over thick Sarcomere shortens, but length of filaments don’t change Heads of myosin (thick) filaments bind ATP so they can bind to actin (thin) filaments Head produces power stroke which moves the actin toward the center of the sarcomere when ADP is released

Muscle Fiber Types Slow fibers better designed for endurance activities Weight lifting stimulates muscle fibers to produce additional myofibrils Each muscle has a mix of the above types