introduction to zoology week 12 - revisedlamarck.unl.edu/zoo/notes/notes2004/week-12.pdf ·...
TRANSCRIPT
Introduction to Zoology WEEK 12
(11/8-11/12)
November 8, 2004
Phylum Enchinodermata – continued from week 11 All Marine – Body fluids are Isosmotic to the sea water – Gastrovascular system – Tube Feet are oriented and move via a combination of muscles and water pressure. Know the cross section images from your book! The ampullae and the tube feet. In the Echinoidea - Aristotle’s Lantern – the picking grinding mouthparts of the sea urchin. Class Asteroidea
• True Sea Stars – originally bilaterally symmetrical but have secondarily derived pentamerous symmetry.
• Body tissues all isosmotic with sea water –
Class Echinoidea • Urchins
o Regular – rounded are used for food by Asian peoples o Irregular – examples are the sea biscuit and the sand dollar.
An echinopleuteus of a sea urchin!
Sand dollars – irregular urchins – the test only! (test is the shell of the urchin)
Strongylocentrotus purporatus- Pacific N.W. Urchin purporatus (purple) Class Holothuroidea
• Sea Cucumbers (fig/ 14.16) • Self evisceration • 3o Bilaterally Symmetrical from a bilaterial larval form to a
radially symmetrical form to a bilaterally symmetrical form for the adult!
Class Crinoidea • Sea Lilies • Feather Stars
Class Ophiroidea • Brittle Stars • Most # of species = most speciose
Phylum Chordata
• Bilaterally symmetrical • Well developed/defined coelom – True coelom {Eucdelic} • Body Cavity lined w/ mesodermally derived peritoneum
_____________________________________________________________ November 10, 2004 Synapomorphies of Chordates
• Notochord – flexibility for animal – provides rigidity. • Dorsal Hollow Nerve Cord (DHNC) • Pharyngeal Gill Arches (pouches)
o Chordates have or manifest these chars @ some stage in development.
• Post Anal Tail • Complete digestive system.
Super Phylum Urochordata • Tunicates • Salps • All marine • Tunic – body protective covering • Solitary feeders – suspension feeders • Filter feeders • Page 292 see that page for more details on the urochordates –
Subphylum Cephalochordata = Craniata • Vertebral column
o Composed of serially repeating units of bone or cartilage in some cases + vertebrate.
• Cranium
Super Class Agnatha (‘No Jaw”) Class Mxini (slime fish)
• No Jaw • Hagfish – blind – detect food by smell – predatory • Marine • Detritus feeders – eat dead stuff
Pacific hagfish -
Class Cephalospidomorphi • Lamprey – ectoparaties • Feed on salmoid fishes
Petromyzon:
November 12, 2004 Petromyzon (Lampreys)
• 22 species in N.A. o Only 11 parasitic
Superclass Gnathostomata Class chondrichthyes (850-900) (Sharks, skates, rays) Squalus – dogfish shark
- Chondrocranium
Chondrocranium of Squalus
Sharks and Rays
• Spiral intestine o Increase surface area = absorptive surface
spiral intestine photo vx. Diagram.
Elasmobrachii
• Rays and sharks • ALMOST ALL MARINE
o Few F.W. à Pomatotrygon – freshwater sting ray • Originally ancestors marine
o Captive of some species in to F.W. o Endosymbionts also made the change into F.W.
• Sharks have continuously growing teeth
Pomatotrygon – with tapeworms – of course! Fresh Water South America
Urolophus halleri the round stingray – I described new species of Eimeria from these