Transcript Vertebrates
Vertebrates P Phylum Chordata • • • • Dorsal hollow nerve cord (nervous system) Notochord Muscular tail during one part of development Internal skeleton of calcified bone or cartilage (or both) • Gill slits behind dorsal opening • Most advanced animal phylum Subphylum Urochordata • Live in salt water • Tough outer covering • Many adults are sessile but some are free swimming • Ex: Sea Squirt, Sea Peach Subphylum Cephalochordata • • • • • Fish like Live in salt water Filter feeders No internal skeleton Ex: Branchiostoma Subphylum Vertebrata • Most have backbone – Supports and protects dorsal nerve cord • Endoskeleton • Distinct head with a skull and brain • 8 Classes (were not covering all of them) What do you see? • • • • • • Class Myxini (Class Agnatha in your book) Ex: Hagfish Jawless Scavengers Lack eyes, short tentacles around mouth Slimy Open circulatory system Hag Fish • Secrete slime • Can secrete enough slime to fill a 5 gal bucket in minutes What do you see? Class Cephalaspidomorphi (Class Agnatha in your book) • • • • • Ex: Lampreys Jawless Nostril on top of the head 7 gill pores Larvae are filter feeders, adults have circular mouth with tooth like structures • Some are parasitic (feed on other fish) What do you see? Class Chondrichthyes • • • • • • Ex: Sharks, skates, rays and chimeras Several gill slits Jaws with teeth Paired fins Tough small scales with spines Ectothermic- regulates body temperature by exchanging heat with surroundings • Two Chambered heart • Males possess structures for internal fertilization Skates and Rays • • • • • Flattened appearance Spreading pectoral fins Flap fins to glide through water No gas bladder so negatively buoyant One family of rays has barb on tail Chimeras • Ratfish • Rare • Found below middle depths Sharks • Attracted to prey by vibrations in the water • More than 80% are less than 2 meters What do you see? Class Osteichthyes • • • • • • Ex: Salmon, perch, Tuna, eel Bony endoskeleton Ectothermic Well-developed respiratory system Have swim bladder Two groups – Ray finned fishes – Lobe-finned fishes Class Osteichthyes • 27,000+ species • 77 million tons taken for human demand(food) • Problems of fish: – Movement – Buoyancy – Gas exchange – Feeding and defense Movements • Small organisms face drag due to viscosity • Turbulence- maximized by streamlining • Swimming adaptations – Tail shape Buoyancy • • • • Counteract the weight Swim Bladder- gas filled structure Due to the density of seawater Fast predators do not have a swim bladder Gas Exchange • Bring oxygen into the body and eliminate the carbon dioxide • Take in water, pump past gill membranes, exhaust through rear facing gill slits Feeding and Defense • • • • • • • • Position of mouth Schooling Lateral line system Countershading and bioluminescence Cryptic coloring Shape Sight Armor plating Types of fish fins Types of Caudal Fins • forked caudal fins are many of the continuous swimmers • lunate caudal fins tend to be the fastest fishes and maintain a rapid speed for long durations • continuous caudal fins (dorsal, caudal, and anal fins attached) are able to swim in and around cracks and crevices. Types of Caudal Fins • rounded caudal fins are usually strong, but slow, swimmers • truncate caudal fins are usually strong, but slow, swimmers