Answer 5 questions Essay Example | Topics and Well Written Essays - 1250 words

Answer 5 questions - Essay Example It is made up of two proteins named fibroin and sericin. There are various mechanical properties of silk depending on the animal that produces it. Spiders, for example, produce dragline silk that has a high tensile strength and a strain that fails at 6%. Other forms of silk produced by spiders, especially the orb-web-spinning spiders, are superior to almost all natural structural materials produced by man and other animals. Another type of spider silk, the viscid silk, possesses remarkable extensibility and maximum strength of over 1 GPa (Meyers et al.). Other structural materials derived from animals include exoskeleton of arthropods, as well as keratin-based hooves and horns (Meyers et al.). Synthetic fibers rayon and nylon are also actually organic in origin. Rayon comes from cellulose, which is the solid part of the plant cell wall. On the other hand, nylon is the first type of fiber that is considered truly synthetic. It is made up of linear superpolymers (â€Å"Miracle Fibersà ¢â‚¬ ). 2. Terrestrial Locomotion Typically, tetrapods have the upper arm and upper leg extended in such a way as it is almost at a straight horizontal line with respect to its body. Moreover, the forearm and the leg form a nearly right angle relative to the body. The body weight of the tetrapod is actually concentrated into the torso or the upper segment with only a small portion of the weight on the upper part of the lower limbs or the area of the thighs. The main task of the limbs is to lift the body off the ground in order to walk. Moreover, the legs of tetrapods have internal bones within them and with muscles that are externally attached in order to facilitate movement. Furthermore, the basic form of the leg of a tetrapod is that it has three key points or joints: the shoulder joint, the knee joint and the ankle joint. The sequence and the arrangement of these joints facilitate movement and make it possible and smooth (Polly). One principle of tetrapod locomotion includes the fact that locomotion must be a compromise or a balancing force between movement and gravity. This means that the animal must always remain in a state of balance whether it is at rest or it is in motion, except when it is falling over. Secondly, the force for locomotion is derived from muscles and gravity. Thirdly, bones and muscles must be regarded as lever systems in order to produce locomotion. Bones and the joints that they form are usually involved in one or more lever systems while muscles are confined to only one lever system. It is the action of these lever systems that produce a forward motion in tetrapods. There are several lever systems suited for each task in the body. However, those lever systems that work the hardest include those that support weight, close jaws or produce forward motion. The heavy muscles, in particular, which are located toward the center of the body and the proximal ends of bones, are actually a major source of movement for the tetrapod body (Polly) . Unlike in bipedal and flying animals whose balance in locomotion centers on the hindlimbs, tetrapods have their balance concentrated over their forelimbs. Moreover, the propulsion for locomotion comes from their hindlimbs, and their head serves to counterbalance the body (Polly). Cats usually have a longer swing duration of the hind limbs, a shorter stance duration, and the same step durations of fore and hind limbs. However, as the cat moves faster, its step duration becomes shorter. These specifics may become slightly different in the case of a