A. The concept of force as a vector 1. Every forces has a direction and a magnitude 2. When two or more forces are produced by a single object, the resultant force can be determined by geometric or trigometric means, e.g., added vectors tail to head. Resultant force indicates what direction movement will occur in and with what force. 3. Every force has an equal but opposite reactant force. B. Use of lateral undulation 1. Sinusoidal wave passes down organisms body. As body bends outward, force is exerted on water column. 2. That force can be resolved into two components, a force along the organisms body and a force at right angles to that force. 3. On opposite side of body there is a reactant force to item 2. This force can also be broken into two components, a force in the direction of movement and a force at right angles to that forces. Because body is oscillating back and forth, the lateral forces cancel each other, but he forward forces indicate the direction and magnitude of the forward movement 4. Forces in item represent frictional forces. C. Use of lever systems 1. Three types a. Class one--fulcrum in middle, in and out forces to either side of fulcrum. In force * mass = to out force*mass. Physical example of teeter-totter. Biological example Animal balanced on legs b. Class two--fulcrum at one end in and out forces opposite ends with in force further out than out. Physical example--wheelbarrow. Biological example Appendages in arthropod c. Class three--fulcrum at one end and in and out forces at opposite end with out force further out than in. Physical example--pulling on fishing pole Biological example--curls D. Appendage movement 1. Inertia/momentum 2. Problem of acceleration/deacceleration 3. Speed of animal based on a. stride length b. number of strides per second 4. Appendage design a. muscle mass near base b. distal portion thin with little mass E. Pressure 1. force per area in a container--always at right angles to surface 2. Use of pressure in hydrostatic functions a. eversion of proboscis b. haemocoel fluids in arthropods. extend legs of spiders so that muscle can then move the legs.