What is the difference between

bony fish's skeleton and cartilaginous fish's skeleton.

Bony fish have a bone skeleton while

Cartilaginous fish have a skeleton of cartilage.

What is the difference between

bony fish's body covering and cartilaginous fish's body covering.

Bony fish have scales as a body covering. 

There are four different kinds of bony fish scales: cosmoid, ganoid, cycloid, and ctenoid.

True cosmoid scales are found only on extinct Crossopterygians.

Ganoid scales are diamond-shaped, shiny, and hard.

Most bony fishes have cycloid or ctenoid scales. Both cycloid and ctenoid scales consist of an outer layer of calcium and an inner layer of connective tissue.

Cycloid scales are circular and smooth. They are most common on fishes with soft fin rays.They overlap from head to tail and help reduce drag as a fish swims.

Ctenoid scales have a characteristic toothed edge. They are most common on fishes with spiny fin rays.

Cartilaginous fish dermal denticles or placoid scales.

Placoid scales have the same structure as a tooth, consisting of three layers: an outer layer of vitro-dentine (an enamel), dentine, and a pulp cavity. Placoid scales are arranged in a regular pattern in sharks and an irregular pattern in batoids.

What is the difference between

bony fish's gill covering and cartilaginous fish's gill covering.

Bony fish have operculum gill covers while

Cartilaginous fin have 5 to 7 pairs of gill slits.

What is the difference between

bony fish's fins and cartilaginous fish's fins.

Some Bony fish have flexible fin rays and some have rigid fins while

Cartilaginous fish have rigid fins.

What is the difference between

bony fish's fertilization and cartilaginous fish's fertilization.

Some Bony fish externally fertilize their eggs and some internally fertilize their eggs while

Cartilaginous fish fertilize their eggs internally.

What is the difference between

bony fish's number of young and cartilaginous fish's number of young.

Bony fish are prolific breeders having 100's of young while

Cartilaginous fish have only a few, 1 - 100 at a time.

What is the difference between

bony fish's buoyancy and cartilaginous fish's buoyancy.

Bony fish have a gas-filled swim bladder while Cartilaginous fish have a fatty liver.

Describe the differences in body shape between sharks and rays.

Sharks are typically have a fusiform body (rounded and tapering at both ends) to reduce drag and requiring a minimum of energy to swim.

Rays are flattened with a ventral mouth and gill slits.

How many years have sharks existed on earth?

Sharks have existed for 350- 400 million years since the Devonian period (the Age of the Fishes).

Where are sharks and rays typically found?

Sharks and rays inhabit tropical and temperate seas as well as some cold and polar seas and freshwater lakes.

What is the largest species of shark?

The Whale Shark is the largest species of shark.

(approx. 40 ft long)

What is the smallest species of shark?

Among the smallest sharks (8-10 in) are:

• Midwater shark
• Pygmy ribbontail catshark
• Dwarf Lantern (6.5in).

What is the largest species of ray?

The Manta Ray is the largest species of ray reaching a width of over 22 ft.

Sharks can be countershaded or camouflaged to blend in with their environment, and some species have markings that change as they age.

Describe how a Zebra Shark changes over its lifetime.

A Zebra Shark pup has dark bands and saddles that fade to rather uniformly distributed spots on adults.

What is a nictitating membrane?

A nictitating membrane is a clear eyelid like structure that retracts laterally across the eye.

How does the nictitating membrane in sharks function?

The nictitating membrane protects the eye from injury from thrashing prey while shark is feeding.

How many teeth can some species of shark replace in their lifetime?

Some species of shark can shed as many as 30,000 teeth in a lifetime.

What are spiracles?

Spiracles originate from rudimentary first gill slits. 

They bring oxygen-carrying water into the gill chamber.

Do all sharks have spiracles?

Not all sharks have spiracles.

Thay are reduced or absent in active, fast swimming sharks.

Describe the scales of Sharks.

Sharks have placoid scales (dermal denticles) having the same 3 layer structure as a tooth (enamel, dentin and pulp.

These scales are arranged in a regular pattern in sharks.

How do scales help Sharks swim more efficiently?

Each placoid scale on a shark come to a hydrodynamic point allowing water to vortex or whirlpool behind each scale helping the shark to swim efficiently.

Do all rays have barbs or spines?

No, not all rays have barbs.

All stringrays have barbs.

Do rays use their barbs aggressively?

No, Stingrays use their barbs defensively against predators.

How can you prevent getting barbed by a stingray?

You can avoid getting barbed by a stingray by letting your presence be known as you walk in shallow water.

The "Stingray Shuffle" which involves sliding your feet along the sandy bottom instead of lifting.

This warns the stingray you are approaching giving them time to flee.

Do all sharks have to keep swimming in order to respire? Explain.

No, only about 50% are Obilgate Ram Ventilators meaning they must swim to move water into their mouth over their gills and out their gill slits.

Other Sharks can respire by opening and closing their mouths or

Use can spiracles to pump water over their gills and can lay motionless for extended periods.

Why do some species of shark have to swim continuously?

Some species of shark need to swim continuously to circulate their blood due to their low blood pressure, muscular contractions are needed to circulate their blood.

Obligate Ram Ventilators need to swim to respire.

Why is the shark's liver important?

A Shark's liver concentrates and stores oils and fatty acids.

The liver functions as an energy store and helps the shark attain neutral buoyancy.

A shark's liver is relatively large, making up 5% to 25% of its total body weight and takes up to 90% of the space inside its body cavity.

Shark's lack a swim bladder.

Describe Shark's Sense of Sound.

S- Sound .

Sharks can detect sounds using their inner ear from up to 820 ft away.

These sounds are often in the form of low frequency pulsed vibrations emitted by injured prey. 

A shark's inner ear can detect sound, acceleration and gravity. 

Describe the Shark's Olfactory sense.

O - Olfactory

Sharks have an extremely acute sense of smell. It is generally accepted that sharks can smell 1 part blood in 1 billion parts water.

What acronym can be used to recall the Shark senses?

SOLVAT

Sound

Olfactory

Lateral Lines

Vision

Ampullae of Lorenzini

Taste 

Describe the Shark's Lateral Line in terms of sense.

L - Lateral Line

The Shark's lateral line system is a series of fluid-filled canals just below the surface of the skin of the head and along the sides of the body.

The lateral line senses low frequency water vibrations and water pressure changes.

Describe a Shark's Vision.

V - Vision

Sharks are well suited for seeing in dim light.

Shark eyes are particularly sensitive to moving objects.

Shark eyes have a layer of reflective plates called tapetum lucidum behind the retina.

These plates act like mirrors to relect light back through the retina a second time increasing vision in dark conditions.

Describe the Shark's Ampullae of Lorenzini.

A - Ampullae of Lorenzini

The ampullae of Lorenzini form a complex and extensive sensory system around the sharks head.

They are jelly filled cavities/pits/pores that detect electrical fields.

This can aid in a number of ways including finding prey buried under a thin layer of sand.

Describe the Shark's sense of Taste.

T - Taste

Sharks have taste buds in their mouth but they have not been studied extensively.

Taste may be responsible for a shark's final acceptance or rejection of prey items.

Describe the Shark's Sensory Pits.

S Sensory Pits

A shark's Sensory Pits are sensory papilla similar to taste buds at the bottom of a slight depression in the skin guarded by enlarged placoid scales.

There are a large number on the back, flank and lower jaw of the shark.

The precise function is unknown.

What types of animals do sharks usually prey upon?

Sharks usually prey upon smaller fish, generally searching for weak, ill, dead or dying fish because they are easier to catch.

Why is it important for Sharks to prey upon smaller fish, generally searching for weak, ill, dead or dying fish?

This opportunistic feeding allows for a reduction in wasted energy.

What clues can Shark teeth give you about that particular species of Shark?

The shape of the Shark's tooth can indicate the type of food they eat.

What type of prey can a shark eat with can opener teeth.

By using the serrated edge with large center point, a shark can eat hard shelled prey such as turtles.

What type of prey can a Shark eat with Knife teeth?

With the serrated edges of the triangular Knife teeth, Sharks can tear large prey such as sea lions into more manageable pieces.

What type of prey can a Shark eat with Fork teeth?

With the long, pointy fork teeth Sharks can stab and grab small fish only needing to be trapped in the Shark's mouth.

What method of feeding do bottom feeders (sharks and rays) use?

Bottom feeding Sharks and Rays stir up sand and gravel uncovering invertebrates that they scrape and grind off the bottom of the ocean.

What method of feeding do filter feeders (whale shark, manta rays) use?

Although they have very tiny teeth, Filter feeding Sharks and Rays filter food by swimming under a school of fish and swimming directly up to gulp their prey into their mouth.

What method of feeding do Thresher sharks use?

Thresher Sharks use their long upper caudal lobe to swat at small fish stunning them long enough to be caught.

What feeding method do Sawfish use?

Sawfish, although naturally lethargic, slash their rostrum side to side when near prey to stun or injure long enough to consume them.

What feeding method do Nurse Sharks use?

Nurse sharks lay in caves or crevices waiting for prey (like crabs and crustaceans) to crawl underneath their mouth so they can suction them into their mouth.

What feeding method do CookieCutter Sharks use?

Cookie cutter sharks latch on to the side of their prey in the water and twist until a clean circular piece is removed. Sick or injured animals seem to be more susceptible to attack.

Explain how Sharks are fed at SeaWorld.

At SeaWorld our sharks are fed twice a week for a total of 1%  of the shark's body weight a week.

There are only 32 species of Shark identified with aggression toward humans or boats.

What do these species have in common?

The Shark species identified as having aggression toward humans or boats have these things in common:

• Prey on fish or marine mammals,
• Grow to a large size,
• Frequent warmer coastal waters where swimmer are likely to be.

What factors contribute to a possible shark attack?

• Sharks confusing humans for an injured prey species
• Humans handling wounded fish
• Territorial displays by the shark that are not related to feeding can all contribute to possible shark attacks

It seems that attacks by Great White Sharks are the most common.

Why is this the case?

Great White Sharks feed on large mammals like seals and sea lions, whose populations are increasing.

How can shark attacks be avoided?

Shark attacks can be avoided by steering clear of seal and sea lion rookeries and other areas frequented by sharks or areas where prey species gather.

Do mother sharks provide maternal care to their pups?

Sharks lack maternal care.

When born or hatched, shark pups are fully formed and physically able to fend for themselves.

Define claspers.

Claspers are the male reproductive organ.

These "finger like" appendages are located directly behind the pelvis fins.

These aid in internal fertilization and grasping the female during copulation.

Name the 3 types of embryonic development in Sharks.

The 3 types of embryonic development in Sharks are:

1. Oviparous
2. Viviparous
3. Ovoviviparous

Explain Oviparous embryonic development in Sharks.

Oviparous Sharks lay eggs.

A gland secretes a shell or case around the egg as it passes through the oviduct protecting the shark until it hatches.

The mother releases the egg in the sea and never returns to care for the pup.

The developing embryo receives nourishment from a yolk formed prior to fertilization.

Explain Viviparous embryonic development in Sharks.

Viviparous Sharks are live bearers.

These sharks develop inside their mother, attached to the uterine wall.

When developed, the pup swims out of its mother and is completely independent.

Explain Ovoviviparous embryonic development in Sharks.

Ovoviviparous sharks are egg retainers and carry eggs inside her 2 uterii and the eggs develop unattached to the uterine wall.

Most nutrients come from the yolk sac, but it is possible nutritive fluids may be absorbed from the surrounding uterine cavity.

The mother in some cases keeps producing infertile eggs to nourish the pups born in her uterii.

This is referred to as oophagy.

What determines the gestation period for sharks and rays?

The gestation period for sharks/rays depends on water temperature and is usually around 2 months.

What sharks has the longest gestation period?

Frilled Sharks have the longest gestation period carrying the young for up to 3.5 years.

How are zoological parks contributing to shark conservation?

Zoological parks contribute to shark conservation by helping educate the public about the plight sharks face and providing support through organizations like SWBGCF.

Label the Shark's External adaptations

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Describe the shark's external adaptation -

Eyes.

In clear water, a shark's vision is effective to about 50 ft.

Sharks have tapetum lucidum which reflects light back into the retina helping increase vision in dark conditions.

Describe the shark's external adaptation -

Nostrils or nares.

Sharks have an acute sense of smell detecting a concentration as low as 1 part per billion of some chemicals.

Describe the shark's external adaptation -

Ampullae of Lorenzini.

The Shark's Ampullae of Lorenzini are small pits that function in sensing weak electrical impulses.

Describe the shark's external adaption -

Lateral line.

The shark's Lateral Line is a row of tiny pores running from head to tail along the sides which sense movement in the water.

Describe the shark's external adaptation -

Gill slits.

Gill slits are openings that allow water to exit the gills during respiration.

Sharks have between 5 and 7 pairs of gill slits

Describe the shark's external adaptation -

Dorsal fin

The shark's dorsal fin provides stability.

Sharks can 1 or 2 dorsal fins.

Some shark's have a dorsal fin that has a free rear tip providing the fin more flexiblity.

Describe the shark's external adaptation -

Pectoral fin.

The sharks paired pectoral fins lift the shark as it swims. Pectoral fins are also used to steer.

Describe the shark's external adaptation -

Pelvic fins.

The shark's paired pelvic fins stabilize the shark.

Describe the shark's external adaptation -

Anal fin.

If present, the shark's anal fin provides stability.

Describe the shark's external adaptation -

Caudal peduncle

The shark's caudal peduncle attaches the caudal fin to the body

Describe the shark's external adaptation -

Caudal fin.

The shark's caudal fin propel the shark as it swims.

The larger the caudal fin the slower the swimmer.

Describe the shark's external adaptation -

Claspers

Claspers are male shark's reproductive organs, located between the pelvic fins.