4Tunicates are members of the subphylum Urochordata Tunicates OverviewTunicates are members of the subphylum UrochordataNicknamed "Sea Squirts"Has body cavity that holds the atriumBilaterally SymmetricalNervous 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 subphylumNicknamed "Sea Squirts"Similar to other chordates while in larva stageUses tail muscles and notochord to swim Settles on substrateLight and gravity cuesRadical metamorphosis where Chordate characteristics disappearBilaterally Symmetrical
5Digestive, Excretory, and Circulatory Systems Incurrent siphon sucks waterAtrium filters foodWater and waste excreted through excurrent siphonFood travels from esophagus to stomachSiphons also function as circulatory systemDigestive 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 InfoCirculates 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.
6Locomotion/Musculature Uses tail muscles and notochord to swim as a larvaeExcurrent siphon can do jet propulsion
7Skeletal Type/Sensory Structures Larval stage has notochord and dorsal, hollow nerve chordIn adult form the skeleton is lost and resorbedLight and gravity sensing cellsLarval stage has notochord and dorsal, hollow nerve chord but as the tunicate goes through radical metamorphosis they are resorbed.
8Reproduction Hermaphrodite = both male/female Settles on substrate Light and gravity cuesChordate characteristics disappear as adult
9Gas Exchange Water is sucked in and pushed out through siphons Diffusion
10Sample Example Organisms Class: Ascidiacea Order: Pleurogona Suborder: Stolidobranchia Family: Pyuridae Genus: Halocynthia Species: H. roretziSea Pineapple
11Lancelets/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 SymmetryFeed on plankton.Adult lancelets up to 5 cm longFrequently swim to new locationsLanclets- globally rare
12Nervous System Lancelets develop a hollow nerve cord Have slightly swollen tip on the anterior end of their dorsal nerve cordHowever, no true brain
13Circulatory SystemWater enters mouth and passes through the pharyngeal slits into the atriumThe atrium is a chamber that vents to the outside by way of the atrioporeNo heart and blood cells
14Digestive System/Excretory System Mucous net around pharyngeal slits remove small food particles from seawaterCiliary pumping draws these particles into the mouthTrapped food enters the intestineFood finally leaves through anus
15Locomotion/Musculature Swimming mechanism of fishesCoordinated contraction of musclesSerially arranged segmental muscles Muscle segments develop from blocks of mesoderm-SomitesUndulatory (wavelike) movements
16Skeletal Type/Sensory Structures As larvae develop a dorsal, hollow nerve cord and notochordSomites found along each side of notochordTentacles by mouth act as sensory devices, and as a water filterNo eyes, or complex sensory structures
17Reproduction Sexual Reproduction Lanclets have separate sexes - Male & FemaleEggs and Sperm released into waterFertilized eggs develop into larvae
18Gas Exchange Diffusion across external body surface Pharynx and Pharyngeal slits play a minor role in gas exchange
19Lancelets are globally rare, but can reach large densities (5000/m2) in areas like Tampa Bay
20QUIZ TIME! 1) Which of following outline the notochord, and are prevalent in all chordate embryos?A. AtriumsB. SomitesC. SiphonsD. Tunics
21QUIZ TIME! 1) Which of following outline the notochord, and are prevalent in all chordate embryos?A. AtriumsB. SomitesC. SiphonsD. Tunics
22QUIZ 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.
23QUIZ 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
24QUIZ TIME! 3. Chordates are A. bilaterally symmetrical. B. radially symmetrical.C. not symmetrical at all.D. aesthetically symmetrical.
25QUIZ TIME! 3. Chordates are A. bilaterally symmetrical. B. radially symmetrical.C. not symmetrical at all. D. aesthetically symmetrical.
26QUIZ TIME! 4. Tunicates _____ and Lancelets _____. A. are sexual; are asexualB. are asexual; are sexualC. have separate sexes; are hermaphroditesD. are hermaphrodites; have separate sexes
27QUIZ TIME! 4. Tunicates _____ and Lancelets _____. A. are sexual; are asexualB. are asexual; are sexualC. have separate sexes; are hermaphroditesD. are hermaphrodites; have separate sexes