PHYLUM CHORDATA

PHYLUM CHORDATA Characteristcs of Chordates: all chordates have 4 characteristics in common at some point in their life cycle: dorsal, hollow nerve tube: in most adult chordates, the posterior part develops into a spinal cord and the anterior part develops into a brain notochord: firm flexible tube just below the nerve tube(backbone in vertebrates), where muscles can attach gill slits: paired openings along the pharynx which functions in filter feeding post-anal tail: at some point during development, a tail reaches beyond the anus There are actually 3 subphylums of chordates, 2 of which are invertebrates)

The Phylum Chordata Includes: Subphylum Cephalochordata (=lancelets) Subphylum Urochordata (= tunicates) Subphylum vertebrata: Class Agnatha - jawless fish Class Amphibia Class Aves – birds Class Chondrichthyes - cartilaginous fish Class Osteichthyes - bony fish Class Reptilia Class Mammalia

* Efficient respiratory systems * Only phylum to have bones