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 ChrondrichthesSharks, skates and rays

Class OsteichthesBony fish

Class ActinopterygiiRay- 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 ex-

current 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

hagfish

lamprey

shark ray

General Bony Fish

Ray finned fish

Lobe-finned fish

Phylum Chordata

http://trc.ucdavis.edu/biosci10v/bis10v/media/ch16/vertebrate_evolution.html