Test Thre1

Test Thre1 - Test Three! Chapter 34 Concept 34.1: Chordates...

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Test Three! Chapter 34        Concept 34.1: Chordates have a notochords and a dorsa, hollow nerve chord Chordates are deuterostome bilaterian animals 2 chordate subphyla are invertebrates  Urochordata Cephalochordata Craniata is also a subphylum of Chordata Figure 34.2   Derived Characters of Chordates All chordates share 4 derived characters Although some species possess some of these traits only during embryonic development Figure 34.3   Tunicates Subphylum Urochordata Deepest-branching lineage of chordates Sessile marine suspension feeders Draws water in through incurrent siphon, filtering food particle Tunicates possess the chordate characteristics during their larval stage  Figure 34.4c   Lancelets Subphylum Cephalochordata Marine suspension feeders  Retain chordate features throughout lifespan Figure 34.5     Concept 34.2 : Craniates are chordates that have a head The origin of the head in chordates allowed some to become active predators Shared characters in craniates Skull Brain Eyes and other sensory organs     Neural Crest Another feature unique to craniates
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A collection of cells appearing near the dorsal margin of the closing neural tube in an embryo Figure 34.7   Hagfishes Class Myxini The least derived extant species of craniate Jawless, marine craniates Cartilaginous skull and axial rod derived from notochord No vertebrae Figure 34.9   Concept 34.3 They have Vertebrae enclosing a spinal chord An elaborate skull Fin rays, in aquatic forms   Lampreys Class cephalaspidomorphi Oldest living lineage of vertebrates  Cartilagenous segments surrounding the notochord and arching partly over the nerve chord Jawless Found in marine and freshwater Figure 34.10   Origins of Bone and Teeth Mineralization appears to have originated with vertebrate mouthparts Conodonts were 1st with mineralized mouth and pharyngeal parts Ostracoderms had mineralized plates on their skin Endoskeleton became mineralized later Figure 34.11 and 34.12   Concept 34.4: Gnathostomes are vertebrates that have jaws The most successful group of vertebrates alive today   The term  agnathan  could be used to describe ______. Conodonts Gnathostomes Conodonts and Myxini Gnathostomes and Conodonts Myxini   Derived Characters of Gnathostomes
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Jaws  Evolved from skeletal supports of the pharyngeal slits Enhanced sensory system, including lateral line system Mineralized endoskeleton  Paired appendages Figure 34.13   Chondrichthyans (Sharks, Rays, and Their Relatives)
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This note was uploaded on 04/11/2008 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Test Thre1 - Test Three! Chapter 34 Concept 34.1: Chordates...

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