BIOL 1108 Lecture Notes - Lecture 22: Echinoderm, Endoskeleton, Tube Feet
Document Summary
Phylum hemichordates: marine-dwelling bottom or filter feeders, small in size, sister group to echinodermata, pharyngeal slits, dorsal hollow nerve cord, not the same body plan as other deuterostomes. Chordates: tunicates, lancelets, and hagfish are chordates without a backbone, so they are not vertebrates, four synapomorphies of all chordates are, dorsal hollow nerve cord, notochord, pharyngeal gill slits, muscular post-anal tail, vertebrate characteristics, vertebrae. Jaws: gill slits become gills, paired appendages, well-developed brain and eyes, cranium, vertebrata have a jointed axial skeleton. Myxini: hagfish: agnatha without jaw, two rows of keratin teeth , produce slime. Petromyzontidae: lamprey: agnatha, most basal extant vertebrate, adults are predaceous and migratory, keratin teeth . Amphibia: means double life : metamorphic life cycle (fish-like larval stage, adult, lunged terrestrial stage, tetrapods that remain dependent on free water for reproduction, eggs must always be kept in moist environments. Sauropsid (amniotes): most have up to 4 egg membranes, desiccation resistant shell, and yolk.
