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Chordata Intro, Urochordata and Cephalochordata

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Presentation on theme: "Chordata Intro, Urochordata and Cephalochordata"— Presentation transcript:

1 Chordata Intro, Urochordata and Cephalochordata

2 Intro to Chordata 40&vid=19992

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

4 Tunicates Overview 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. Tunicates are members of the subphylum Urochordata

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

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

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 Sea Pineapple zi-Sea_pineapples_at_Tsukiji_Market-01.jpg Class: Ascidiacea Order: Pleurogona Suborder: Stolidobranchia Family: Pyuridae Genus: Halocynthia Species: H. roretziAscidiaceaPleurogonaStolidobranchiaPyuridaeHalocynthia

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 o 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/m 2 ) 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


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