BZ 214 Lecture Notes - Lecture 6: Neopterygii, Endoskeleton, Actinopterygii
Document Summary
Whale sharks believed to travel the oceans of the world. We begin to see changes between cartilaginous fish and bony fish. Cartilaginous fish have placoid scales, which aid in reducing turbulence over body. Pelvic fins on back portion of body. Osmoconformers - body fluids slightly hyperosmotic to seawater, higher blood solute concentration (not salt concentration), solute concentration affects diffusion. Solute concentration very similar, slightly higher than environment. All types of fertilization seen in chondrichthyes. In every ecological niche found, sharks are one of the top predators of that ecological niche, why they are sometimes referred to as one of the most successful of the vertebrates. Modern fish have cycloid or ctenoid scales. Pectoral fins move up along side of body. Pelvic fins are now anterior but still ventral. Anal fin is in the place of chondrichthyes pelvic fin. Transition away from oily liver to use of swim bladder - most bony fish do not move continuously like cartilaginous fish do.
