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Invertebrate Chordates. http://funscubadiver.com/gallery/belize-scuba-photo/belize-painted-tunicate.jpg. Characteristics. Lancelets and Tunicates Tadpole-like larvae A notochord, semi-flexible rod running down the length of the animal A dorsal nerve cord
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Invertebrate Chordates http://funscubadiver.com/gallery/belize-scuba-photo/belize-painted-tunicate.jpg
Characteristics • Lancelets and Tunicates • Tadpole-like larvae • A notochord, semi-flexible rod running down the length of the animal • A dorsal nerve cord • Pharyngeal slit, an opening between the throat and the outside • Post-anal tail, waste is excreted at the posterior end • Aquatic animals
Classes within the Phylum: Leptocardii (Cephalochordate) http://en.wikipedia.org/wiki/File:Branchiostoma_lanceolatum.jpg
Classes within the Phylum: Ascidiacea (Urochordata) http://en.wikipedia.org/wiki/File:BU_Bio.jpg
Classes within the Phylum: Larvacea (Urochordata) http://jellieszone.com/images/oikopleura.jpg
Classes within the Phylum: Appendicularia (Urochordata) http://www.meer.org/M20.htm
Classes within the Phylum: Thaliacea (Urochordata) http://www.meer.org/M20.htm
Body Plan • A characteristic of the invertebrate chordates is bilateral symmetry (symmetry along one axis) • Very long, tubular body structure • Little specialization • Segmentation of the embryo usually occurs early in development • Has a coelomate (fluid-filled body cavity) • Is a deuterostome (first opening of the embryo becomes anus while the opposite side becomes the mouth) http://www.bumblebee.org/invertebrates/images/AmphioxusLanceolatus.jpg http://biodidac.bio.uottawa.ca/ftp/BIODIDAC/ZOO/CHORDATA/DIAGBW/UROC005B.GIF
Body System: Feeding • Are filter feeders of the water; Lancelets use their pharyngeal-gill slits to take in water • Lancelets burrow in soft ground with their mouth facing upward to filter-feed • Urochordates take in water to their body cavity to siphon food (usually plankton) • Plankton gets entangled on the mucus on the endostyle (cavity wall) http://comenius.susqu.edu/bi/202/Animals/DEUTEROSTOMES/cephalochordata/uwinnipeg-Lancelet.jpg
Body System: Respiration • Lancelets (cephalochordata) do not use the gills for respiration but resperate through their skin • Urochordata use an internal gill to extract oxygen from the water they take in http://www.bethel.edu/~johgre/bio114d/LowerVerts.html
Body System: Circulation Lancelets: • closed circulatory system (has vein and vessels) • pumped by ventral aorta to branched vessels • Lacks a heart • Colorless blood • Urochordatas: • Open circulatory system • Has a ventral heart • Contains high levels of metal in blood such as lithium and vandium
Body System: Excretion • Lancelets have a one way stream of wastes that exit the anus • Urochordates take in water through one entrance, extract the food and oxygen before pumping out another entrance http://www.emc.maricopa.edu/faculty/farabee/BIOBK/chordate.gif http://ian.umces.edu/imagelibrary/displayimage-4350.html
Body System: Response Lancelets: • Has a dorsal nerve running down its body • Slightly larger end at the front which is its brain • Cephalization occurs • Urochordatas: • Has a nervous system in the larvae stage • Digests its own brain in the mature stage • Nervous system soon disintegrates
Body System: Movement Lancelets: • Are feeble swimmers • Use contraction of muscles to move the tail from side to side • Urochordata: • Are motile during their larvae stage; they have a tail to swim with • Once they become mature, they attach to a substrate and become non-motile
Body System: Reproduction Lancelets: • Is gonochoristic (there’s a male and female individual) • Releases the appropriate sex cell into the water • Fertilization is external • Develops into a larvae stage • Urochorata: • Contain both male and female parts (hermaphrodites) • Do not fertilize themselves but send sperm out to fertilize other indivduals • Keeps the eggs inside themselves
Work Cited • “Chordata.”Bumblebee. 2010. Web. 4/16/2010. http://www.bumblebee.org/invertebrates/CHORDAT A.htm • “Subphylum Urochordata (tunicates)” Meer. Web. 4/16/2010. http://www.meer.org/M20.htm • “Introduction to the Urochordata.” UCMP. 4/16/2010. http://www.ucmp.berkeley.edu/chordata/urochordata. html • “Introduction to the Cephalchordata.” UCMP. 4/16/2010. http://www.ucmp.berkeley.edu/chordata/cephalo.html