BIOL 1002 Study Guide - Midterm Guide: Agnatha, Cartilage, Chordate
Document Summary
The last group of animals features four new characteristics: Lies above the digestive tract on the upper- dorsal- portion of body, unlike other animals (fig. Becomes thick at one end (anterior) that will become the brain. A stiff, but flexible rod running the length of the body between the digestive tract and nerve cord. Provides support, but in many it"s only present in early development until skeleton takes over. In others, only present in early embryonic development. The organisms with these (and other features) are the: Secrete massive amounts of slime as a defense mechanism. Fins formed by webs of skin supported by bony spines. Other bony fish have lobed fins (fleshy fins w/ rod-shaped bones surrounded by muscle) Thought to be extinct for 80 million years! Straddle life on land with life in water. Lungs are not well developed and skin is used for respiration too. In some, the fertilized egg develops into tadpoles.
