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Slide 1 Kingdom Animalia Phylum Chordata Subphylum Vertebrata All vertebrates share the following fundamental characteristics: A backbone called a vertebral column Nerve cord or spinal cord Bilateral symmetry Endoskeleton
The most primitive of any of the types of fish
They lack jaws
They lack paired fins
The only two species in this class:
Hagfish are entirely marine, benthic scavengers that secrete a thick slime from glands in their skin to protect them from predators
They can tie their body in a sliding knot to clean their body of excess slime or help tear food apart
Lampreys are anadromous meaning that the fish will move from a marine environment to a freshwater for spawning
They are parasitic using hook shaped teeth within their oral disc (mouth)
Sharks are torpedo shaped. Their tail is used for propulsion. They have 2 dorsal fins and all of the fins have cartilage supporting them.
Claspers are used for reproduction.
The skin of sharks is covered by a protective layer of scales called Placoid Scales. They are also called denticles. These scales have a small tooth like projection and gives the skin a sand paper type of texture.
The spiracle is remnant of a gill slit. The gill slits are where the water comes out with the carbon dioxide wastes.
The Liver functions to store surplus nutrients for the body and detoxify certain substances.
Sharks have a Spiral Valve and it serves to increase the surface area of the intestine to be able to absorb nutrients into the blood stream for use throughout the body.
The Kidneys help regulate or balance the blood chemistry ( all the chemicals found in the blood) waste products are passed through an urogenital opening.
Shark skeleton is flexible with fewer joints; therefore, the body is less maneuverable. The skeleton is made of cartilage, not bone. Cartilage is a tough, elastic connective tissue.
The claspers on the males are inserted into the female and sperm passes along a groove into the female. Some sharks lay eggs in a leathery case. Others have young develop inside the female. No sharks care for their young after hatching.
Sting-Rays, Manta Rays, Eagle Rays and Skates are cartilaginous fish.
They have flat bodies and wing like pectoral fins that are attached to the head.
Since Skates and Rays are bottom dwelling, if they tried to take in water through their mouth they could choke because they would take in sand at the same time. The spiracles located near their eyes are for taking in water. Water passes over the gills and then comes out of the gill slits located on the underneath side of them.
Skates are harmless, bottom dwelling fish. Their diet is shellfish, worms and crabs; they have strong jaws that can easily crush the shells.
Male skates have claspers and females produce a leathery egg case that hooks onto seaweed. Empty egg cases are called Mermaid’s purses.
Sting Rays are similar to Skates, but they have a long whip like tail with a stiff spine or barb. The spine is used for defense. Venom is released from the spine which is painful but not fatal.
Sting rays give birth to live young.
Sawfish is a shark like ray found in warm waters. The sawfish slashes through schools of fish with its saw-like nose eating those fish that he injured. Sawfish do not have a stinging barb (spine).
The skin also secretes a slimy mucus over the scales which acts as a barrier against infection and reduces the amount of friction as the fish moves through the water.
The color of fish is due to chromatophores (pigment cells) and iridocytes (reflective cells) in the skin.
observed with different mouth types.
Attackers- jaws with long sharp teeth
for seizing and holding prey
Pickers- stout jaws with protruding teeth
for crushing a variety of food
Probing & Sucking- have tube-like snouts
& small mouths
Grazers- have fused teeth with a sharp
cutting edge used for scraping
Grubbers- will blow jets of water into the
ocean bottom or have barbels
that hang from their lower jaw
which will move over the ocean
bottom finding food
Swim Bladder is a gas filled sac that the fish can inflate or deflate to maintain buoyancy or its ability to float or rise in the water. Neutral buoyancy is the ability to maintain a steady position in the water, so the fish neither floats up to the surface nor sinks to the bottom.
Fish have an excellent sense of smell and good vision.
Fish have external fertilization, sperm and eggs are released into the water where they will hopefully find each other with the exception of certain species such as the seahorse.