BIOl 152 1st Edition Lecture 24Outline of Last Lecture I. Lophotrochozoaa. Platyhelminthesb. Molluscac. AnnelidaII. Ecdysozoa a. Nematodesb. Arthropods III. Deuterastomes a. EchinodermataOutline of Current Lecture I. ChordatesII. CraniumIII. VertebratesIV. GnathastomesV. OstheichthyansVI. Lobe finsVII. TetrapodsVIII. AmniotesCurrent LectureI. ChordatesThe hallmarks of the chordates are they contain notochords (an endoskeleton), Dorsal hollow nerve cord, pharyngeal gills, and a post anal tail. The clades of the chordates are the Cephalochordate, the tunicate, and the cranium. The Cephalochordate is commonly known as lancelets, is mostly marine and use the pharyngeal gills to concentrate food and gas exchange and are filter feeders. The tunicates are the sister taxa to the craniate and are mostly marine and are also filter feeders.II. CraniumThe Cranium is chordates and a synapamorphy is that they have neural crest cells that help create bone and cartilage of the head. Cranium refers to their skull.III. VertebratesA synapamorphy is that they contain vertebral column that surrounds the dorsal hollow nerve cord and provide the organisms with protection.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.IV. GnathastomesOrganisms in this clade contain jaws that arose from the modification of pharyngeal gill arches. They contain mineralized skeletons, and paired appendages. Examples are sharksand rays.V. OstheichthyansThese organisms contain lungs or lung derivatives that are derived from the gut. They have hard, bony, calcified skeletons. They have swim bladders that allow them to stay afloat and not sink.VI. Lobe FinsThese organisms have lobed pectoral fins and the other characteristics of craniates and chordates. VII. TetrapodsThese organisms contain four limbs with digits, and signified the movement from water to land. The first land vertebrates, the amphibians, required moist habitat to lay their eggs and the gas exchange was through their skin.VIII. AmniotesThese organisms contain an amniotic egg. This egg is specialized and allowed for the diversification of land species. The shell protects the embryo from drying out and acts asa shock absorber. The egg also allows for gas exchange. Mammalians are a class in this clade and contain mammary glands and hair. They have placenta that is an intimate connection between mother and embryo, it is highly vascularized. The placenta providesnutrients and gasses to the
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