five internal ________ lead into cavities called gill pouches, which lead to the outside by external ______.
What are gill slits?
100
Sharks have the ability to determine the direction of a given _____ based on the timing of ______ detection. This is similar to the method mammals use to determine direction of sound. (one answer)
What is scent
100
The three means sharks have been known to bear young.
What is oviparity, viviparity and ovoviviparity
100
longitudinal folds that help in the churning and mixing the food with digestive juices.
What are rugae
100
These scales, also called denticles, are similar in structure to teeth, and have one median spine, and two lateral spines.
What is a placoid scale
200
The gill slits are supported by cartilaginous __________.
What are gill arches
200
This is an internal sense that allows sharks to detect vibrations in the water - it is primary used to find their prey in the water as well as the location of other sharks that may be in the area.
What is the lateral line
200
Sharks practice internal fertilization; for this reason, male sharks have _________ to help transfer sperm into the oviduct.
What are claspers
200
A smooth, shiny membrane seen lining the inside of the body wall.
What is the peritoneum
200
Due to their lack of swim bladder, sharks rely on their large _________ to stay bouyant. It contains oils filled with squalene.
What is the liver
300
gill slits are guarded by small cartilaginous papillae-like ________ which act as strainers to prevent food particles from leaving the pharynx through the gill slits.
What are gill rakers
300
Some species of sharks have protective a __________. They will use them when they are being attacked or when they are attacking prey. This is an instinct reaction that helps to ensure their sight isn’t hindered during the process.
What is the nictitating membrane (or Third Eye-lid)
300
Oviparious sharks encase their eggs in an egg case with a consistenc similar to ________. Once empty, this case is referred to as "the mermaid's purse"
What is leather
300
The membrane in which visceral organs are suspended dorsally by a double membrane of peritoneum
What is mesentery
300
Sharks are ________, meaning their body temperature is based on their ambient surroundings.
What is poikilothermic
400
The gills are provided with a rich blood supply. Arteries run directly from the nearby heart to the gills bringing deoxygenated blood into the _______. Oxygen diffuses from the ventilating water current flowing over the gills into the blood.
What are gill lamellae (Gill filaments)
400
Like humans, and unlike teleost fish, SHarks have the ability to both ______ and ________ their pupils to help allow them see. (two answers)
What is contract and dilate
400
Parthenogenesis has had at least two documented cases in sharks in which females gave birth ___________.
What is asexually
400
The screw-like, symmetrical shape within the valvular intestine. It adds surface area for digestion and absorption to an otherwise relatively short intestine.
What is the spiral vlave
400
Filters the salt from the shark's blood
What is the rectal gland
500
A modified slit called a ________ lies just behind the eye; the ________ assists water intake during respiration and plays a major role in bottom–dwelling sharks. They tend to be reduced or missing in active pelagic sharks.
What are Spiracles
500
Electroreceptor organs that allows sharks to detect the electromagnetic fields produced by all surrounding life forms.
What is the Ampuellae of Lorenzini
500
Oophagy has been documented in certain shark species. This means that in utero, some shark pups in Ovoviviparious species have been known for...
What is embryotic(intrauterine) canniballism
500
The last portion of the alimentary canal. It collects the products of the colon as well as the urogenital ducts.