A. Arthropods--Other thoughts on flight 1. Three modes of wing use a. gliding b. vortex production c. rowing oneself through the air 2. Gliding was discussed in previous outline 3. Vortex production a. use of clap-flap action. Wings are raised upwards, leading edge towards medial surface. Wings are then flapped outwards. Air moving over foil surface is forced off the surface at the wing tip and produces a donut-shaped vortex of air that moves away from the creature and produces the force that allows the creature to move forward/upward. b. very common mode of locomotion in dipterans 4. Rowing onewself through the air a. Only used by very small creatures. Wings are very fuzzy rather than being shaped as a foil. b. Creature uses the viscosity of the air to maintain position vertically in the air mass. Wings are used to move creature foward. B. Arthropods--Other uses of appendages 1. Locomotion in the mole crab, Emerita analoga a. Walking appendages are modified for digging--Use an appendage length with a longer in length than out-length. Strong muscles in coxal segment produced a large force at tip of appendage. Tip of appendage only moves short distance, but large force can be produced, such as produced by pry bar. b. Animal uses antennae for foodgetting--Rushes up with a wave and quickly buries itself in the sand by digging in backwards. By vibrating appendages the sand behaves as a liquid and thus allows the creature to bury himself/herself more rapidly. Antennae are laid on sand and as water flows through the sieve produced by the setae on the antennae food particles are filtered out. 2. Horseshoe crab a. Lives in environments with muddy/sandy bottom. Last pair of appendages rather than being pointed look like a circlet of small paddles, which can be used to push against the substrate. The other appendages are pointed. b. As appendages are moved in the locomotory process, their bases rub against each other. Basal segments have series of spines (teeth). These will grind up the food materials. These "chewed" materials will be passed forward to the mouth. c. Horseshoe crab eats food such as clams, polychaete worms, snails, etc., so the process described above works very well for them. 3. Lobsters and crabs a. Use auxillary appendage associated with mouthpart to maintain circulation through branchial chamber b. Mouthparts consist (in anterior to posterior order) a. mandibles b. two-pair of maxillae c. three-pair of maxillipeds c. Last maxilliped has an appendage called the scapho- gnathite. As mouthpart works the scaphognathite causes current of water to pass from posterior entrance to branchial chamber forward to pass out anteriorly just beneath rostrum. d. Because the carapace encloses the branchial chamber, water in that chamber would stagnate and thus the gills attached either to coxal segments,or to lateral sides of body, would not be very functional The current produced by the scaphognathite maintains a high concentration gradient at the gill surface which allows the gases to move through the membranes. 4. Brine shrimp a. Animal is located in very salty bodies of water, eg., the Great Salt Lake, Mono Lake. Hatches as nauplius, then metamorphoses into adult. Adult swims upside down. As appendages beat, they cause a current that passes along the animals ventral surface and organism filters food particles from this current. C. Echinoderms 1. Use of water vascular system--sytem consists of tube feet, radial canals in each of the arms, a circular canal in disk area, a vertical canal that reaches the surface at the madreporite. The vertical canal is filled with a calcareous matrix and is called the Stone canal. Thoughts are that it filters the fluid that passes through the madreporite to get into the water vascular system. 2. Tube foot actually consists of the tube foot and an ampullae. The ampullae has muscles which can be used to squeeze water into the tube foot. Tube foot also has circular and longitutdinal muscles which can cause it to be long and slender or short and squat. Animal is using fluid in the system as a water skeleton to contract against. Because the system is under high pressure, fluid "leaks" out and this explains the use of the rest of the system to replace lost fluids 3. Tube feet are applied against the substrate or prey and a slight vacuum at the end is produced to keep foot attached to the substrate. Creature can use tube feet for locomotion by walking them in the direction the creature wishes to go. Individual tube feet may fatique, but since there are many tube feet the animal can move very slowly foward, or can apply a strong force when opening a mussel or clam. 4. Problems in movement are related to coordination amongs the five arms. One arm must lead, and the other four must follow. In effect, what happens is that the leading arm sends out information that inhibits the other arms from taking charge.