1. Phylum Chordata the chordates

2. Phylum Chordata chordates
Primary characters include:
Notochord

3. Phylum Chordata Primary Characters
pharyngeal gill slits
dorsal nerve cord
ventral heart
post anal tail

4. Phylum Chordata Secondary Characters
tailed larvae or direct development
dorsal and ventral blood vessels; closed circulatory system
endoskeleton

5. Phylum Chordata Includes two groups:
Protochordata or Acraniata – those without a cranium
Craniata – those with a cranium

6. Phylum Chordata Group Protochordata (=Acraniata) (the first chordates)
Includes two subphyla:
Urochordata – tunicates or sea squirts
Cephalochordata- lancelets

7. Subphylum Urochordata (tunicates or sea squirts)
about 2000 species
all marine, free-living or sessile, solitary or colonial
adult has no coelom; no segmentation, no bones
have a test or tunic; made of cellulose

8. Subphylum Urochordata (tunicates or sea squirts)
dorsal atrium, chamber used for filter feeding
there is a heart, with colorless blood
respiration is probably function of pharynx

9. Subphylum Urochordata (tunicates or sea squirts)
notochord is restricted to tail, and is found only in larvae (except for one class- there are 3 classes)
larvae are called "tadpole larvae“

10. Subphylum Urochordata (tunicates or sea squirts)
most species are hermaphroditic, fertilization is external
some species reproduce asexually through budding

11. Subphylum Cephalochordata (lancelets)
about 23 species
all marine, free-living or sessile, solitary or colonial, live on bottom
no well developed head

12. Subphylum Cephalochordata (lancelets)
many gill slits in pharyngeal basket, act in excretion and respiration
have a tail; projects behind anus
muscles arranged in blocks- myotomes
have a notochord made of muscle fibers

13. Subphylum Cephalochordata (lancelets)
are microscopic suspension feeders
has closed circulatory system, with colorless blood
sexes are separate; fertilization is external

14. Phylum Chordata Group Craniata (the vertebrates)
Includes one subphylum:
Subphylum Vertebrata

15. Phylum Chordata Subphylum Vertebrata
Contains a wide variety of animals that include:
Class Myxini – hagfishes
Class Cephalaspidomorphi – lampreys
Class Chondrichthyes – sharks and rays
Class Osteichthyes- bony fishes
Class Amphibia – amphibians
Class Reptilia – reptiles
Class Aves – birds
Class Mammalia - mammals

16. Subphylum Vertebrata Divided into: Without useable jaws
Agnatha
With useable jaws
Gnathostomata

17. Subphylum Vertebrata Earliest vertebrates were jawless:
Agnathans
Earliest of these were Ostracoderms
500 million years ago

18. Subphylum Vertebrata Earliest jawed vertebrates or Gnathastomes
Earliest of these were Placoderms
400 million years ago