The surface velocity of a river is measured at several locationsx and can be reasonably represented byV = V0 + V(1 eax),where V0, V, and a are constants. Find the Lagrangian descriptionof the velocity of a fluid particle flowing along the surface if x =0 at time t = 0.
Phylum Platyhelminthes - Flatworms, Flukes, Tapeworms Animalia Parazoa Eumetazoa Protostomia Spiralia Platyzoa – flatworms, rotifers Trochozoa – mollusks, annelids Ecdysozoa Deuterostomia Platyzoans are animals that Are usually acoelomate Are usually flat Use cilia to help move around Often have very complex mouth parts (“jaws”) Phylum Platyhelminthes – Flatworms 18,500 species, from Greek platys = flat, helminthes = worm Flatworms, flukes, and tapeworms Cephalized - flatworms are looking back! Acoelomate - solid body, except for GVC (gasceo vascular cavity) Most primitive animal with all three germ tissue layers (ectoderm, mesoderm, endoderm) Such animals are called triploblastic Dorsoventrally flattened (advantage) Rely on diffusion - no respiratory or circulatory systems First animals with true organs - ovaries, testes etc. First animals with true systems - digestive system, excretory system Sticks out a tubular pharynx to feed Digests food in a complex GVC Complex excretory system Excrete ammonia by diffusion Water and other wastes pass through simple tubes called protonephridia Specialized cells called flame cells drive fluid through the protonephridia Complex nervous system Two lateral nerve cords Rudimentary “brain” (cerebral ganglion) Primitive sense organs
