NOTE: Formal Lab Write-Up (With On-Line Template)

SHARK DISSECTION Pre-lab Preparations NOTE: ☼ Formal Lab Write-up (with on-line template) A. Bring to lab: 1. 4 large black garbage bags 2. 4 kitchen size white garbage bags 3. 4 pairs latex gloves 4. Small bottle Dawn dishwashing liquid (blue or orange) for extra credit. B. DO NOT wear open-toed shoes of any kind to lab. C. Tie back long hair and bring an old shirt to wear. D. Label Exterior Shark Diagram (cut out & put in results, diagrams, include title) E. Record functions of external structures (put in results, under data, table form, w/ title) F. Label Interior Shark Diagram (cut out & put in results, diagrams, include title) Shark dissection website with videos: http://www.amnh.org/learn/pd/sharks_rays/rfl_dissection/ Watch the following video clips: 1. Intro. to specimen 2. Overview of specimen 3. Dissection : opening the two cavities 4. Liver dissection: watch, but DO NOT REMOVE THE LIVER! 5. Description of Alimentary canal

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12 8 11 7 10 3 External Anatomy of Dogfish Shark Internal Anatomy – Dogfish Shark

Anatomy of the Shark – Functions of External Structures the dogfish shark, Squalus acanthias.

The dogfish is a small predator that occurs along both coasts of the Atlantic Ocean. This shark has internal fertilization, with the eggs being retained in the mother during their development (ovoviviparous). The young are then born live. The dogfish has the longest gestation period of any of the sharks, extending for 16 – 20 months. Usually two to six pups are born per litter and will measure approximately six inches long.

The terms to be covered during the examination of external anatomy include:

1. Spiracle: modified gill slit for water intake to mouth and gills

2. Lateral line: sensory cells that pick up vibration in water from over a 600 yard distance!!! 3. Gill slits: water passes over gills and respiration occurs

4. Anterior dorsal fin: bears spine for protection from enemies

5. Posterior dorsal fin: bears spine for protection from enemies

6. Caudal fin: drives shark forward

7. Pectoral fin: swimming and steering

8. Pelvic fin: swimming and steering

9. Clasper: if specimen is a male, these fingerlike extensions of the pelvic fin will be used to transfer sperm to the female during mating. 10. Mouth: note ventral location

11. Nostrils: paired nostrils for olfactory sense can detect blood from a distance of ¼ mile. (one part blood in 100 million parts of water) 12. Ampullae: tiny pores in the face for picking up electric fields in the water to help guide the shark and locate prey at minimal distances. Placoid Scales: Dermal denticles of the shark’s skin with a similar structure to teeth – gives a sandpaper feel. You will have the opportunity to feel this later.