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Phylum Chordata. Protostome vs. Dueterostome Development Chordates and Echinoderms have deuterostome development, and so are considered related.
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Protostome vs. Dueterostome DevelopmentChordates and Echinoderms have deuterostome development, and so are considered related.
Objectives: Describe characteristics of phylum Chordata, compare to other phyla. Examine key evolutionary developments within the vertebrates.S4, C4, PO 5: Analyze how patterns in the fossil record, nuclear chemistry, geology, molecular biology, and geographical distribution give support to the theory of organic evolution through natural selection over billions of years and the resulting present day biodiversity. Phylum Chordata • Subphylum Cephalochordata- Lancelets • Subphylum Urochordata- Tunicates • Subphylum Vertebrata • Class Myxini- Jawless fishes • Class Chondrtichthyes- Sharks & Rays • Class Osteithchyes- Bony Fishes • Class Amphibia- Amphibians • Class Reptilia- Reptiles • Class Aves-Birds • Class Mammalia- Mammals
Phylum Chordata • At some point in the lifecycle, all Chordates have : • Dorsal hollow nerve cord • Notochord • Pharyngeal pouches • Post-anal tail
The Notochord allows for more effective movement. • Lancelets are filter feeders with no brain.
Dorsal Hollow Nerve Cord • All Chordates have one. • Only sub-phylum vertebrata has a spine.
Dorsal Hollow Nerve Cord • The nerve cord is continuous with the brain.
Pharyngeal Pouches • All Chordates have pharyngeal pouches at some stage in their development.
Pharyngeal Pouches • In some aquatic chordates, such as fish, the pharyngeal pouches become gills.
Pharyngeal Pouches • In humans the pharyngeal pouches become part of our ears, tonsils and thyroid glands.
Post-anal Tail • Remember, some chordates do not have all these features (such as a post-anal tail) as adults, but at some stage in their development.