- Basic Info
-Vertebrates enclose and protect the nerve cord(spinal cord) which ends at the brain.
Jawless Fishes
-The most primitive fishes living today
-Feed by suction with the aid of a round, muscular mouth and rows of teeth
-Body is cylindrical and elongated like that of eels or snakes
-They lack paired fins and scales
-Feed by suction with the aid of a round, muscular mouth and rows of teeth
-Body is cylindrical and elongated like that of eels or snakes
-They lack paired fins and scales
Cartilaginous fishes
--Also known as chondrichthyes
-Ancient group includes: sharks, rays, skates, and ratfishes
-"Bones" are made of cartilage which is lighter and more flexible than bones
-Possess movable jaws that have well developed teeth
-Mouth is almost always ventral
-Contained paired lateral fins for efficient swimming
-Rough, sandpaper-like skin because of tiny placoid scales. These scales have a pointed tip that's directed backward
-Incredibly adapted for fast swimming and predatory feeding
-"Living fossils"- many of them are similar to species that lived over 100 million years ago.
-Their tail(caudal fin) is well developed and powerful
-Upper surface of the body has 2 dorsal fins
-Sharks have 5-7 gill slits on each side of he body behind the head
-Ancient group includes: sharks, rays, skates, and ratfishes
-"Bones" are made of cartilage which is lighter and more flexible than bones
-Possess movable jaws that have well developed teeth
-Mouth is almost always ventral
-Contained paired lateral fins for efficient swimming
-Rough, sandpaper-like skin because of tiny placoid scales. These scales have a pointed tip that's directed backward
-Incredibly adapted for fast swimming and predatory feeding
-"Living fossils"- many of them are similar to species that lived over 100 million years ago.
-Their tail(caudal fin) is well developed and powerful
-Upper surface of the body has 2 dorsal fins
-Sharks have 5-7 gill slits on each side of he body behind the head