Chapters 50 - 748 Unit VII Animal Form and Function Animals...

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748 Unit VII Animal Form and Function Animals that hop generate a lot of power in their hind legs by momentarily storing energy in their tendons. Maintaining balance is also essential for running, walking, or hopping. Bipedal animals keep part of at least on e foot on the ground when walking. When running, momentum more than foot contact keeps the body upright. Crawling animals must exert considerable effort to overcome friction. 3. Flying Flying animals do not use a skeleton for support during motion, and must almost completely overcome gravity to become airborne. Wings must provide enough lift to overcome gravity; the key is in the shape of the wings. B. Skeletons support and protect the animal body and are essential to movement Skeletons function in support, protection, and movement. Help maintain shape of aquatic animals. Hard skeletons protect soft body tissues. Skeletons provide a firm attachment against which muscles can work during movement. 1. Hydrostatic skeletons Hydrostatic skeletons consist of fluid held under pressure in a closed body compartment. Found in most cnidarians, flatworms, nematodes, and annelids Control form and movement by using muscles to change the shape of fluid-filled compartments Provide no protection and could not support a large land animal The hydrostatic skeleton of earthworms and other annelids allows for the rhythmic locomotion ( peristalsis ) these animals are known for (see Campbell, Figure 49.23). 2. Exoskeletons Exoskeleton = Hard encasement deposited on the surface of an animal Mollusks are shed (molted) as the animals grow. 3. Endoskeletons Endoskeleton = Hard supporting elements buried within the soft tissues of an animal Sponges possess hard spicules of inorganic material or softer protein fibers. Echinoderms have ossicles composed of magnesium carbonate and calcium carbonate forming hard plates beneath the skin. Chordates have cartilage and/or bone skeletons divided into several areas. The vertebrate frame is divided into an axial skeleton (the skull, vertebral column, and rib cage) and an appendicular skeleton (limb bones, pectoral and pelvic girdles) (see Campbell, Figure 49.24).
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This note was uploaded on 02/08/2012 for the course BIOL 119 taught by Professor Hannam during the Spring '11 term at SUNY Geneseo.

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Chapters 50 - 748 Unit VII Animal Form and Function Animals...

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