BIOL-2111 Study Guide - Dermal Bone, Ostracoderm, Pronephros
Document Summary
Paired pharyngeal gill slits, dorsal tubular nerve cord, notochord, post-anal muscular tail, subpharyngeal gland that binds iodine (endostyle or thyroid) Pharyngula stage in vertebrate development: pharyngula stage shows the basic chordate characteristics present in all vertebrates. Shared derived characters: outgroups/sister groups are the most distant relatives to the other species, sympleisiomorphy shared primitive trait such as the vertebrae (backbone) of tetrapods. Hemichordates (e. g. acorn worms and pterobranchs); 80 species 2cm-2m: pharyngeal gill slits, deuterostomes, but not chordates, filter feeders that burrow. The protochordates ( lower chordates : marine filter feeders use cilia to create a current to bring in food particles which are then trapped on mucus strands produced by an endostyle. Tunicates/urochordates 2000 species: ascidians- sea squirts (1900 sp. , tunic: tunicin and rare vanadium metal, pharynx takes up most of body o, gill slits are spirals to increase surface area.