Non-Vertebrates

1
Non-Vertebrates

• Period 5
• Umer Khan
• James Trimble

2
General Characteristics

• Small filter-feeders
• Lack big brains and enhanced sensory structures
• Has a set of characters that unifies the phylum
• a notochord
• A perforated pharynx (gill silts)
• A dorsal nerve cord
• A post anal-tail

3
Classes within the phylum

• There are two subphyla

1. Urochordata
2.Cephalocordata
represented by Tunicates
represented by Lancelets
http//www.tunicates.com/tunicates.jpg
http//www.nationmaster.com/wikimir/images/upload.
wikimedia.org/wikipedia/commons/thumb/a/a0/Branchi
ostoma_lanceolatum.png/250px-Branchiostoma_lanceol
atum.png
4
Body Plan Tunicates
http//kentsimmons.uwinnipeg.ca/16cm05/16labman05/
lb7pg1_files/tunicates.jpg
5
Body Plan Lancelets
http//kentsimmons.uwinnipeg.ca/16cm05/16labman05/
lb7pg1_files/amphioxsis.jpg
6
Feeding Tunicates

• Suspension feeders
• Two openings in their body cavity
• In-current intake food and water
• Ex-current expels waste and water
• Feed by filtering sea water through pharyngeal
  slits
• Primary food source is plankton
• Pharynx is covered by ciliated cells which allow
  consumed plankton to pass through the esophagus.

7
Feeding Lancelets

• Suspension feeders
• Water passes from the mouth into the large
  pharynx
• Lined by gill-slits
• The ventral surface of pharynx contains the
  endostyle
• Endosytle produces a film of mucus
• Ciliary action pushes the mucus in a film over
  the surface to the gill slits, trapping suspended
  food particles as it does so.

8
Respiration

• Lancelets
• Have no respiratory system
• Breathe solely through their skin
• Skin consists of a simple epithelium
• Little respiration occurs in the gill slits
• Silts are primarily devoted to feeding
• Tunicates
• Gas exchange occurs across the gill and also
  across the lining of the atrium

9
Circulation

• Lancelets
• The circulatory system does resemble that of
  primitive fish in its general layout, but is much
  simpler, and does not include a heart.
• There are no blood cells
• No hemoglobin
• Tunicates
• Controlled by blood vessels that circulate
  through the exoskeleton

10
Excretion

• Lancelets
• The excretory system consists of segmented
  kidneys containing protonephridia instead of
  nephrons
• There are numerous, segmented gonads
• Tunicates
• Wastes are excreted through the intestine
• The intestine ends as an anus in the atrium below
  the atrial aperture

11
Response

• Lancelets Tunicates
• Have a dorsal nerve cord not protected by bone
• Protected by notochord
• Do not posses a true brain
• No complex sense organs comparable to those of
  vertebrates

12
Movement

• Lancelets
• Have a translucent, fish-like body, but without
  any paired fins or other limbs
• Poorly developed tail fin
• Are not efficient swimmers
• Do posses some cartilage but no true skeleton for
  movement
• Tunicates
• Movement is controlled by the cerebral ganglion
• Movement is equivalent to the human brain

13
Reproduction

• Lancelets
• Have separate sexes
• Equal numbers of males and females
• Egg and sperm are released into the water
• The fertilized eggs develop into larvae
• Tunicates
• Reproduce asexually and sexually
• Reproduce by budding
• Have one testes and the ovary organ inside the
  body
• Fertilization takes place outside and eggs are
  produced inside

14
WORKS CITED

• Bassham, Susie. "Chordates." N.p., 2010. Web. 20
  Apr 2010. lthttp//www.neuro.uoregon.edu/postle/peo
  ple/Bassham.htmlgt.
• Holland, L.Z. "Early Development in the
  Lancelets." The Biological Bulletin. Marine
  Biological Laboratory, 1992. Web. 20 Apr 2010.
  lthttp//www.biolbull.org/cgi/content/abstract/182/
  1/77gt.
• "Lancelets Cephalochordata." Animals Jrank. Net
  Industries, 2010. Web. 20 Apr 2010.
  lthttp//animals.jrank.org/pages/1663/Lancelets-Cep
  halochordata-BEHAVIOR-REPRODUCTION.htmlgt.