Download Phylum Chordata

Phylum Chordata
(Part 1: Lower Chordates)
[Exercise 17, p265 & Exercise 18, p 275]
Bio 1413: General Zoology Lab
Ziser, 2008
Identifying Characteristics of the Phylum
-dorsal, hollow, tubular nerve cord
-notochord for support
-paired gill (pharyngeal) slits
-segmentation in some systems
-most with postanal tail
-deuterostome development
Body Organization and Charactristic Structures
-cartilaginous notochord for support in larva, adult or both
-pharynx used for filter feeding and/or respiration
Classification:
Subphylum: Urochordata (Tunicates)
- solitary or colonial; microscopic to 1 ft in diameter
-motile larvae with dorsal nerve cord and notochord
-adults sessile and lacking these characteristics
-no cranium or braincase
Subphylum: Cephalochordata (Lancelets)
-burrow in sand; active swimmers
-elongated, streamlined,fishlike vertebrates with all chordate characteristics in adult stage
Subphylum: Vertebrata (vertebrates)
-all chordate characteristics in either the embryonic or adult form
-well developed cephalization
-endoskeleton with cranium enclosing the brain and vertebrae enclosing the spinal cord
Lab Activities:
Subphylum: Urochordata
1. The Adult Tunicate (p 266):
Ecteinascidia is a sessil benthic sea squirt;
Salpa, Doliolum, and Oikopleura are planktonic
look at each slide and try to find the following:
tunic, incurrent and excurrent siphons, gill slits, pharynx,
gill slits, digestive tract, anus, muscle bands
2. Ascidian Larvae (p 269):
know: adhesive papillae, branchial basket, intestine,
atriopore, notochord
Slides: Ecteinascidia wm,
Salpa, Doliolum,
Oikopleura
Slides: Ascidian tadpole &
ascidian swimming tadpole
Subphylum Cephalochordata
3. Amphioxus (p270):
Slide: Amphioxus immature, wm
know: rostrum, oral cirri, notochord, fin rays, myomeres,
dorsal nerve cord, pharynx, gill slits, hepatic caecum,
intestine, anus
4. Amphioxus cross sections (p 273):
Slide: Amphioxus representative cs
cross section through pharyngeal region: skin, epidermis,
dermis, dorsal fin, fin ray, myomeres, dorsal nerve cord,
notochord, pharynx, gill slits, gill bars, atrium, gonads,
metapleural fold, ventral aorta
cross section through intestinal region: dorsal fin, fin ray, dorsal
nerve cord, notochord, myomere, dorsal aorta, intestine,
ventral fin
Subphylum Vertebrata
5. The Adult Lamprey (Ex 18, p 278):
external anatomy; know: dorsal fin, caudal fin, rasping
teeth, eyes, median nostril, gill slits, lateral line, anus
Preserved Specimens,
plastimount
observe the prepared sagittal sections to find the internal anatomy;
know: notochord, brain, spinal cord, myotomes, digestive
tract, oral hood, mouth, tongue, esophagus, intestine
with typhlosole, pharynx, liver, gonad, kidneys, heart
6. Lamprey Larva, Ammocetes (Ex 18, p 275):
know: oral tentacles, eye, caudal fin, myotomes,
gill pouch, notochord, brain, spinal cord,
intestine, cloaca
Slide: Ammocetes, wm
Demonstrations:
• Similarities between the larvae of Hemichordates and Primitive Chordates
• Deuterostome Evolution & Generalized Chordate
• Vertebrate Relationships
• Representative Urochordates (tunicates)
• Metamorphosis in Tunicates
• Representative Cephalochordates
• Phylum Chordata; Class Agnatha
Notebook Suggestions:
 How do sessile and planktonic tunicates differ from each other
 How does the anatomy differ between larval and adult tunicates
 Compare tunicate larvae with lamprey larvae; what are the similarities, what are the differences
Disposal:
Do not discard, return preserved animals to bucket