photo/belize-painted-tunicate.jpg
TRANSCRIPT
http://funscubadiver.com/gallery/belize-scuba-photo/belize-painted-tunicate.jpg
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
http://en.wikipedia.org/wiki/File:Branchiostoma_lanceolatum.jpg
http://en.wikipedia.org/wiki/File:BU_Bio.jpg
http://jellieszone.com/images/oikopleura.jpg
http://www.meer.org/M20.htm
http://www.meer.org/M20.htm
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
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
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
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
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://ian.umces.edu/imagelibrary/displayimage-4350.html
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/chordate.gif
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
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
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
“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