Biology 3484A/B Lecture Notes - Deuterostome, Electric Eel, Bilateria
24 Dec 2012
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Bilateria deuterostomia: synapomorphies are specialized embryonic development and dna sequence data. Groups that are branches of deuterostomia include echinodermata (ex. starfish) and chordata (ex. cheetah). Bilateria deuterostomia echinodermata: these are seemingly simple organisms, but they share much of our dna. Bilateral symmetry means there is only one way to cut it while having identical sides. Adults appear to have radial symmetry, but it is actually unique pentaradial symmetry. They have distinct front and rear ends and always burrow with their front end first. Their mouth and anus are separated by a complete gut. Bilateria deuterostomia chordata: a synapomorphy of this group is a hollow nerve cord. Includes tunicates (hollow nerve cord in the larval stage), hagfish, and vertebrates. Bilateria deuterostomia chordata craniata: synapomorphy is skull or cranium, and no cartilaginous backbone. Bilateria deuterostomia chordata craniata vertebrata: synapomorphy is vertebral column or backbone. Vertebrates sharks and rays: they have full cartilaginous skeletons, which are flexible and not as hard as bone.
