Transcript Invertebrate Chordates

http://funscubadiver.com/gallery/belize-scubaphoto/belize-painted-tunicate.jpg
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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
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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/Amphio
xusLanceolatus.jpg
http://biodidac.bio.uottawa.ca/ftp/BIODIDAC/ZO
O/CHORDATA/DIAGBW/UROC005B.GIF
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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 filterfeed
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/DEUTER
OSTOMES/cephalochordata/uwinnipegLancelet.jpg
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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/LowerVe
rts.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
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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.marico
pa.edu/faculty/farabee/
BIOBK/chordate.gif
http://ian.umces.edu/imagelibr
ary/displayimage-4350.html
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
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“Chordata.”Bumblebee. 2010. Web. 4/16/2010.
http://www.bumblebee.org/invertebrates/CHOR
DAT
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/urochor
data.
html
“Introduction to the Cephalchordata.” UCMP.
4/16/2010.
http://www.ucmp.berkeley.edu/chordata/cephalo.
html