Phylum Chordata
Chordates
Basic Overview
• Four main qualities make a Chordate. At some
time during their development (humans
included) Chordates have
– A Notocord
– Pharyngeal Gill Slits
– Post-anal tail
– A Hollow dorsal nerve cord
Phylum Chordata
-Subphylum Urochordata (tunicates)
-Subphylum Cephalochordata
(lancelets)
-Subphylum Vertebrata(Craniata)
Class Agnatha
Jawless fish; hagfish and
lampreys
Class Chrondrichthes
Sharks, skates and rays
Class Osteichthes
Bony fish
Class Actinopterygii
Ray- finned fish
Class Sarcopterygii*
Lobe-finned fish
*Allowed for the evolution of 4 limbed amphibians
Subphylum Urochordata
(tunicates)
• Sac-like filter feeder
– They have an in-current and an excurrent siphon
– Primary food is Plankton
• The only animal able to create
cellulose
• The tunicate blood is incredibly
interesting. It contains vanadium
and vanadium-associated
proteins. Some Tunicates can
concentrate vanadium up to one
million time that of the
surrounding water.
Bluebell Tunicates
Subphylum Cephalochordata
(lancelets)
• Found buried in temperate and
tropical water
• Often harvested for food for
humans and animals
• Their notocord extends into the
head unlike the vertebral cord.
This is what gives the subphylum
its name : cephalo – meaning
related to the head.
Subphylum Vertebrata
(Crainata)
• This is the last step to vertebrate
evolution. Unlike the lancelets or
tunicates, this subphylum
developed craniums instead of
hard tissue to protect their
growing brains and other
receptive organs.
Pictures of classes
lamprey
General Bony
Fish
hagfish
shark
ray
Lobe-finned fish
Ray finned fish
Phylum Chordata
http://trc.ucdavis.edu/biosci10v/bis10v/media/ch16/vertebrate_e
volution.html