BIOL 150 Lecture Notes - Lecture 3: Chondrichthyes, Endoskeleton, Amniote
Document Summary
Deuterostomes: are monophyletic, internal skeletons segmentation less obvious mouth forms toward anus. However: deuterostomes include invertebrates; invertebrates include proto- and deuterostomes. All deuterostomes are considered to be bilateral . Although echinoderms are radial (but have bilateral larvae) No brain, circulatory system, radial symmetry, has hard plate endoskeleton. Pharyngeal gill slits are openings to the throat. Runs length of body and composed of nerves. Notochord stiff but flexible rod; extends length of body, supports body. Phylum chordata (however: not all chordates are vertebrates) Phylum chordata has three sub-phyla (we"ll just skip to the vertebrates) The dorsal hollow nerve cord is the spinal cord (which are nerves that run from the brain to the posterior) Vertebrae - notochord secretes proteins that induces its formation. Vertebrates: about half are fish; half are tetrapods. Vertebrae of cartilage or bone (protects spinal cord) endoskeleton of cartilage or bone. Column of cartilaginous or bony structures called vertebrae (protects the spinal cord)
