1. Intro, Urochordata and Cephalochordata
Victor Pontis & Kaushik Sahoo
AP Bio Period 3
Rall

2. Intro to Chordata

3. Characteristics of Chordata
Deutorosomes, Bilaterally Symmetrical
Four key characteristics:
Notochord - skeletal
Dorsal, hollow nerve cord - CNS
Pharyngeal slits or clefts – “gills”
Muscular, post-anal tail

4. Tunicates are members of the subphylum Urochordata
Tunicates Overview
Tunicates are members of the subphylum Urochordata
Nicknamed "Sea Squirts"
Has body cavity that holds the atrium
Bilaterally Symmetrical
Nervous system degenerates after larval stage. Some cells detect light and gravity allowing it to settle on a substrate. Limited nervous system in adult stage. 
Member of Urochordata subphylum
Nicknamed "Sea Squirts"
Similar to other chordates while in larva stage
Uses tail muscles and notochord to swim 
Settles on substrate
Light and gravity cues
Radical metamorphosis where Chordate characteristics disappear
Bilaterally Symmetrical

5. Digestive, Excretory, and Circulatory Systems
Incurrent siphon sucks water
Atrium filters food
Water and waste excreted through excurrent siphon
Food travels from esophagus to stomach
Siphons also function as circulatory system
Digestive and Execretory Info: Incurrent siphon to bring in water passes through pharyngeal slits into atrium that filters particles of water. The filtered water then passes out an excurrent siphon. The atrium has a mucous net that traps food particles and cilia that transports them to the esophagus. Food travels from esophagus to stomach and after it is process it leaves through the intestine and finally the anus and excurrent siphon.
Circulatory Info
Circulates water with incurrent and excurrent siphons. The water is sucked in and it brings other stuff with it. The two siphons are the only modes of absorption and excretion.

6. Locomotion/Musculature
Uses tail muscles and notochord to swim as a larvae
Excurrent siphon can do jet propulsion

7. Skeletal Type/Sensory Structures
Larval stage has notochord and dorsal, hollow nerve chord
In adult form the skeleton is lost and resorbed
Light and gravity sensing cells
Larval stage has notochord and dorsal, hollow nerve chord but as the tunicate goes through radical metamorphosis they are resorbed.

8. Reproduction Hermaphrodite = both male/female Settles on substrate
Light and gravity cues
Chordate characteristics disappear as adult

9. Gas Exchange Water is sucked in and pushed out through siphons
Diffusion

10. Sample Example Organisms
Class: Ascidiacea Order: Pleurogona Suborder: Stolidobranchia Family: Pyuridae Genus: Halocynthia Species: H. roretzi
Sea Pineapple

11. Lancelets/Cephalochordata
In the lavaral form lancelets develop a notochord, a dorsal, hollow nerve cord, numerous pharyngeal slits, and a post-anal tail.
Body Cavity is present.
Bilateral Symmetry
Feed on plankton.
Adult lancelets up to 5 cm long
Frequently swim to new locations
Lanclets- globally rare

12. Nervous System Lancelets develop a hollow nerve cord
Have slightly swollen tip on the anterior end of their dorsal nerve cord
However, no true brain

13. Circulatory System
Water enters mouth and passes through the pharyngeal slits into the atrium
The atrium is a chamber that vents to the outside by way of the atriopore
No heart and blood cells

14. Digestive System/Excretory System
Mucous net around pharyngeal slits remove small food particles from seawater
Ciliary pumping draws these particles into the mouth
Trapped food enters the intestine
Food finally leaves through anus

15. Locomotion/Musculature
Swimming mechanism of fishes
Coordinated contraction of muscles
Serially arranged segmental muscles 
Muscle segments develop from blocks of mesoderm-Somites
Undulatory (wavelike) movements

16. Skeletal Type/Sensory Structures
As larvae develop a dorsal, hollow nerve cord and notochord
Somites found along each side of notochord
Tentacles by mouth act as sensory devices, and as a water filter
No eyes, or complex sensory structures

17. Reproduction Sexual Reproduction
Lanclets have separate sexes - Male & Female
Eggs and Sperm released into water
Fertilized eggs develop into larvae

18. Gas Exchange Diffusion across external body surface
Pharynx and Pharyngeal slits play a minor role in gas exchange

19.
Lancelets are globally rare, but can reach large densities (5000/m2) in areas like Tampa Bay

20. QUIZ TIME! 1) Which of following outline the notochord, and
    are prevalent in all chordate embryos?
A. Atriums
B. Somites
C. Siphons
D. Tunics

21. QUIZ TIME! 1) Which of following outline the notochord, and
    are prevalent in all chordate embryos?
A. Atriums
B. Somites
C. Siphons
D. Tunics

22. QUIZ TIME! 2) Mature tunicates are able to move by A. their muscles.
B. clinging to other animals as they pass by.
C. teleportaion. 
D. jet propulsion.

23. QUIZ TIME! 2) Mature tunicates are able to move by A. their muscles.
B. clinging to other animals as they pass by.
C. teleportaion. 
D. jet propulsion

24. QUIZ TIME! 3. Chordates are A. bilaterally symmetrical.
B. radially symmetrical.
C. not symmetrical at all.
D. aesthetically symmetrical. 

25. QUIZ TIME! 3. Chordates are A. bilaterally symmetrical.
B. radially symmetrical.
C. not symmetrical at all.  
D. aesthetically symmetrical. 

26. QUIZ TIME! 4. Tunicates _____ and Lancelets _____.
A. are sexual; are asexual
B. are asexual; are sexual
C. have separate sexes; are hermaphrodites
D. are hermaphrodites; have separate sexes

27. QUIZ TIME! 4. Tunicates _____ and Lancelets _____.
A. are sexual; are asexual
B. are asexual; are sexual
C. have separate sexes; are hermaphrodites
D. are hermaphrodites; have separate sexes