Question | Answer |
notochord | a flexible rod that supports the animal's back |
cartilage | a connective tissue that is softer than bones, but flexible and strong. |
vertebrae | similar bones lined up in a row, like beads on a string |
endoskeleton | internal skeleton |
ectotherm | an animal whose body does not produce much internal heat -- its body temperature changes depending upon the temperature of its environment |
endotherm | an animal whose body controls and regulates its temperature by controlling the internal heat it produces |
fossil | the hardened remains or other evidence of a living thing that existed a long time in the past |
sedimentary rock | made of hardened layers of sediments, particles of clay, sand, mud, or silt. |
fish | a vertebrate that lives in the water and has fins, which are structures used for moving. |
jawless fishes | skeleton made of cartiloage and do not have fins and mouths do not have jaws. their mouths have structures for scraping, stabbing, and sucking. |
catilaginous fishes | skeleton made of cartilage, have jaws and pairs of fins, pointed, toothlike scales voer their bodies, carnivores |
bony fishes | have skeletons made of hard bone, body coved with scales and gills |
swim bladder | an internal gas-filled sac that helps the fish stabilize its body at different depths |
buoyant force | the force that water exerts upward on any underwater object |