BIOL 1002 Chapter : More Animals The Chordates Chapter 24
Document Summary
The last group of animals features four new characteristics: __nerve cord_______________ lies above the digestive tract on the upper- dorsal- portion of body, unlike other animals (fig 23-11: becomes thick at one end (anterior) that will become the brain. ____notocord__________: 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. __tails____________: posterior extension that continues past the anus. The organisms with these (and other features) are the: __lack jaws__________________: hagfish, grind and tear food w/a tongue-like structure w/teeth. Secrete massive amounts of slime as a defense mechanism. Mammals include marsupials, monotremes, and placental mammals: cartilaginous fish, have jaws, cartilage skeletons. Fins formed by webs of skin supported by bony spines: diversity of ray-finned fishes, other bony fish have __lobed fins_________________
