Why is the dogfish shark a model organism to dissect?

Why is the dogfish shark a model organism to dissect?

During this activity you will observe and dissect a shark to develop a better understanding of vertebrate anatomy’ The dogfish shark is an excellent model organism for comparative vertebrate anatomy due to its size and availability.

What are the characteristics of a dogfish shark?

Spiny dogfish are slim, with a narrow, pointed snout and characteristic white spots. They are gray above and white below. They have two dorsal fins with ungrooved large spines. Males grow up to 3.3 feet, and females grow up to 4 feet.

How many fins do dogfish sharks have?

two dorsal fins
This long, slender dogfish has a pointed snout, large eyes, and spines in front of its two dorsal fins.

What is the benefit of having a cloaca in sharks?

The cloaca serves for the elimination of urinary and fecal wastes as well as an aperture through which the young “pups” are born. The two uteri open into the posterodorsal portion of the cloaca just ventral to the urinary papilla.

What special structure is located inside the intestine of a dogfish shark?

The rectal gland is a slender, blind-ended, finger-like structure that leads into the intestine by means of a duct. It has been shown to excrete salt (NaCl) in concentrations higher than that of the shark’s body fluids or sea water. It is thus an organ of osmoregulation, regulating the shark’s salt balance.

What kind of shark do you dissect?

dogfish shark
Dissecting a dogfish shark allows students to develop their dissection and observation skills, identify major external and internal features of the shark, understand form and function, and gain a better understanding of vertebrate and fish anatomy.

What is the difference between dogfish and shark?

Smooth Dogfish. This small, slender shark has elongated cat-like eyes, triangular fins, and an asymmetrical, notched caudal (tail) fin. Unlike most sharks, this dogfish has rows of flat grinding teeth rather than sharp blades, which are ideal for crushing and chewing the crustaceans and mollusks that it hunts.

What kind of shark is a dogfish?

dogfish, (order Squaliformes), any of several small sharks making up an order of chondrichthyian fishes composed of the families Centrophoridae (gulper sharks), Dalatiidae, Echinorhinidae, Etmopteridae, Oxynotidae, Somniosidae, and Squalidae. In North America the name is also used for a freshwater fish, the bowfin.

What is the anatomy of a dogfish shark?

Anatomy and Physiology Dogfish Distribution External Anatomy of the Dogfish Shark •Double dorsal fin –anterior dorsal finis larger than the –posterior dorsal fin –Presence two spines •one immediately in front of each dorsal fin •spines carry a poison secreted by glands at their base. •The paired pectoral fins

How do I perform a shark dissection?

1. Place your shark ventral side up on the dissection tray. 2. Using scissors – blunt tip inside the shark – make a cut from the left side of the jaw (the shark’s left) caudally down through the middle of the gill slits and through the pectoral girdle down to just above the cloaca.

What equipment do I need to dissect a dogfish shark?

Activity: Dogfish Shark Dissection Duration:2 hours Materials You will be dissecting a dogfish shark: Squalus acanthias. The equipment you will be using includes:  a large dissection tray  surgical scissors  scalpel  probe  forceps Dissection is a learned skill that takes practice and patience. Some general rules to remember are:

How does the shark bring water into the pharynx?

The shark can bring water into its pharynx to the gills by way of the spiracle and mouth. Urogenital Anatomy of the Dogfish Shark •Thekidneys are flattened, ribbon-like, darkly colored structures lying dorsally on either side of the midline, along the entire length of the body cavity.