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_Sharks _
By: James
Different Types of Sharks By: Anonymous INTRODUCTION Although sharks belong to
the class Chondrichtyes, there are many different types. Sharks arose about
350 million years ago and have remained virtually unchanged for the past 70
million years and still comprise a dominant group. It is thought that sharks
almost certainly evolved from placoderms, a group of primitive jawed fishes.
It took a long series of successful and unsuccessful mutations with fin, jaw
positions etc to give us all the different designs of sharks around today.
When asked to draw a shark, most people would draw a shape along the lines of
the whaler shark family, tigers or a mackeral shark such as a porbeagle.
However many people do not realize the sheer diversity in the shape of sharks,
or that rays are really sharks. Seldom does such an animal inspire such a
variety of emotions reflecting a mixture of fascination, awe and fear. Sharks
have occasionally exacted a terrible price from humans who have trespassed on
their territory. No better understood than the ocean that they inhabit, these
creatures should be regarded in the same way as lions, tigers, and bears: as
dangerous, predatory but nonetheless magnificent animals. Different Types of
Sharks Living sharks are divided into eight major orders, each easily
recognizable by certain external characteristics. Each order contains one or
more smaller groups, or families. In all there are 30 families of sharks and
they contain the 350 or more different kinds or species of sharks. The eight
major orders of sharks include the Squantiformes, Pristiophormes,
Squaliformes, Hexanchiformes, Carcharhiniformes, Lamniformes,
Orectolobiformes, and the Heterodotiformes. The orders have distinguishing
characteristics that fit in each. The Squantiformes normally have flat bodies
that are ray-like with mottled dorsal surfaces. These sharks have a short
terminal mouth, which is armed with small impaling teeth. They also have a
caudal fin, which has a lower lobe that is longer than the upper lobe. Their
pectoral fins extend forward over the ventrally directed gills. The
Pristiophormes have more of an elongated snout, which is saw-like and edged
with slender, needle-sharp lateral teeth. They have two dorsal fins and no
anal fin. They use short transverse mouths and small cuspidate holding teeth
in both jaws. Squaliformes have no anal fin as well, but their snout is not
elongated, but is somewhat long. Many have powerful cutting teeth in both
jaws. In some species these razor sharp teeth are in the lower jaw only and
the upper teeth serve to hold the food. Hexanchiformes have six or seven gill
slits. They are sharks with a single spineless dorsal fin, and an anal fin.
The typical Carcharhiniforme has an elongated snout, a long mouth that reaches
behind the eyes, an anal fin and two spineless dorsal fins. The eyes have
movable, nictitating lower eyelids worked by unique muscles. Teeth vary from
small and cuspidate or flattened to large and bladelike. Carcharhiniformes
have no enlarged rear crushing teeth. Along with this they have a spiral
scroll intestinal valve. A Lamniforme shark has an elongated snout. Most have
long mouths that reach behind the eyes, an anal fin and two spineless dorsal
fins. They also have a ring intestinal valve. The Orectolobiformes have
pig-like snouts and short mouths that in most species are connected to the
nostrils by grooves. There is an anal fin but no fin spines on the two dorsal
fins. They have uniquely formed barbells at the inside edges of the nostrils.
Heterodotiformes are the only living shark that combines fin spines on their
two dorsal fins and anal fin. They only have five-gill slits. In each order
there are specific types of sharks. Each shark belongs to a family with
different species. The Angel shark (Squantiforme) is just one of the many. It
has a single family of about thirteen species. They are all ovoviviparous
livebearers and most do not exceed 1.5 meters. Saw sharks (Pristiophoriformes)
are harmless bottom sharks. They are also a single family but with five
species. They are also ovoviviparous livebearers. Four sharks that belong to
the order Sqauliforme are the Bramble, Dogfish, and Rough sharks. They have
three families with eighty-two species. They too, are ovoviviparous
livebearers. They have more cylindrical bodies. Frilled sharks, Six, and Seven
gill sharks (Hexanchiformes) have two families and five species. Once again
they are also ovoviviparous livebearers. Usually, these guys are found in deep
waters. The Catsharks, Finback Catshark, False Catshark, Barbelled Houndshark,
Weasel, Houndshark, Hammerhead, and Requiem sharks (Carcharhiniformes) have
one hundred and ninety-seven known species. Most of these sharks are known to
be dangerous. They are both oviparous and ovoviviparous livebearers. This is
not the type of shark you would like to have grace you presence. From the
order of Landformes is the Sand, Basking, Goblin, Crocodile, Megamouth,
Thresher, and Mackerel sharks. They come complete with seven families and
fifteen or sixteen species. All of them are ovoviviparous livebearers. These
sharks are found in all seas except Arctic and Antarctic. The last group of
sharks would be the Collared Carpet sharks, Blind, Wobbegongs, Zebra,
Longtailed Carpet Sharks, Whale, and Nurse sharks. They all belong to the
order Orectolobiformes and have seven families and thirty-three species. These
sharks prefer the warmer water and are both ovoviviparous and oviparous
livebearers. Obviously these sharks come in many different sizes and some are
more dangerous than others. At least eighteen species in four families and
nine genera have been implicated in attacks on humans. Obviously a small shark
such as the Pygmy is harmless, but they still must be treated as a predator
especially the bigger ones. The smallest of all sharks is the Pygmy Ribbontail
Catshark, which is about 0.24 meters. Next in line from smallest to largest
would be the Port Jackson Shark, which is about 1.65 meters. After them would
be the Ornate Wobbegong (2.88m) and then the Bull shark (3.4m). The average
sizes go drastically up from there to the Great White shark, which is
incredibly larger, its about 6.4 meters. The two greatest sizes are the
Basking shark (7.8m) and the Whale shark (13.7m). These sharks listed here are
definitely not all the sharks in the world, they were just meant to give an
average range of size for all sharks. Some of the most dangerous sharks range
from about 2 to 8 meters. The Hammerhead, Great White, Tiger, Blue, and the
Bull shark name a few. There are many types of sharks lurking around in
todays ocean. In every one is unique in its own way. Some are different by
size, shape, eating habits, or even the way they breed. Although with all
these differences they are all very similar and that is why the shark is one
of the most amazing creatures of our time. Summary Although sharks belong to
the class Chondrichtyes, there are many different types. Sharks are divided
into 8 major orders. Each order contains 1 or more smaller group. There are
350 or more different kinds of species of sharks. The 8 orders are named the
Squantiformes, Pristiophormes, Squaliformes, Hexanchiformes,
Carcharhiniformes, Lamniformes, Orectolobiformes, and the Heterodotiformes.
These orders group sharks according to certain distinguishing characteristics.
The Angel shark, Saw shark, Frilled shark, Hammerhead shark, Sand shark,
Wobbegongs, and more all belong to a specific order due to their
characteristics. Each one of these sharks come in different shapes and sizes.
Some are more dangerous than others. The more dangerous sharks range from
about 2 to 8 meters. It is obvious that sharks are one of the most amazing
creatures of our time. Among some of the most wasteful reasons to hunt in the
world Id have to say that besides the killing of elephants for their tusks,
this is on top of the list for one of the worst reasons a blue shark is
killed. And sadly enough the United States is one of the top countries to
blame. In Hawaii and Mexico shark finning is very common. The fishermen fish
the sharks take the fins, and throw it back into the water. The fins are
mainly used for fin soup as a status symbol for the Japanese. They eat it for
fin soup. Since the fins contain a high dose of ammonia smell and taste they
must be processed quickly and tossed back into the ocean, and a lot of times
the fish is thrown back into the water alive. Conservations main cause for
concern is the fact that the sharks have a very low reproduction rate. They
dont typically reproduce until the age of twenty-five, and even then they
only produce a few babies. At The rate these fishermen hunt them the sharks
will possibly become endangered in the next few years. This is one of the most
cruelest things Ive ever heard, and not just the killing of them for the
fins, but that fact that they are thrown back into the water without fins. How
is the shark supposed to survive and even swim? That is so cruel. Maybe
someone should cut off fishermens legs and arms, and watch them try to
survive. It probably would probably hard for the fisherman to survive, hed be
a physical vegetable. I hope the United States does something urgently to
control this growing problem before it gets out of hand. The people can do
something about it by obviously not buying shark products but also by writing
letters and sending petitions to congress, we could also spread the word in
other ways in Japan and Hong Kong. But I think if the US stopped the finning,
other countries would probably follow and sales would go down, giving the
sharks a chance to live and breed in peace. Bibliography Works Cited Clark J.
1975. Shark frenzy. Grosset &Dunlap Publishers, New York NY. 106 pp. Clark, E.
1981. Sharks, magnificent and misunderstood. National Geographic 160:138-186
(Aug. 1991) Compagno, L. J. V. 1984. FAO species catalogue. Vol. 4. Sharks of
the world. An annotated and illustrated catalogue of shark species known to
date. Part 2. Carcharhiniformes FAO Fish. Synop. (125) Vol. 4, Pt. 2: 251-655.
Conniff R. 1993. From jaws to laws - now the big bad shark needs protection
from us. Smithsonian 24: 32-43 (Number 2, May1993). Burgess, R. F. 1970. The
sharks. Doubleday &Company, Inc., Garden City NY. 159 pp Word Count: 1252
_Bibliography _
Different Types of Sharks By: Anonymous INTRODUCTION Although sharks belong to
the class Chondrichtyes, there are many different types. Sharks arose about
350 million years ago and have remained virtually unchanged for the past 70
million years and still comprise a dominant group. It is thought that sharks
almost certainly evolved from placoderms, a group of primitive jawed fishes.
It took a long series of successful and unsuccessful mutations with fin, jaw
positions etc to give us all the different designs of sharks around today.
When asked to draw a shark, most people would draw a shape along the lines of
the whaler shark family, tigers or a mackeral shark such as a porbeagle.
However many people do not realize the sheer diversity in the shape of sharks,
or that rays are really sharks. Seldom does such an animal inspire such a
variety of emotions reflecting a mixture of fascination, awe and fear. Sharks
have occasionally exacted a terrible price from humans who have trespassed on
their territory. No better understood than the ocean that they inhabit, these
creatures should be regarded in the same way as lions, tigers, and bears: as
dangerous, predatory but nonetheless magnificent animals. Different Types of
Sharks Living sharks are divided into eight major orders, each easily
recognizable by certain external characteristics. Each order contains one or
more smaller groups, or families. In all there are 30 families of sharks and
they contain the 350 or more different kinds or species of sharks. The eight
major orders of sharks include the Squantiformes, Pristiophormes,
Squaliformes, Hexanchiformes, Carcharhiniformes, Lamniformes,
Orectolobiformes, and the Heterodotiformes. The orders have distinguishing
characteristics that fit in each. The Squantiformes normally have flat bodies
that are ray-like with mottled dorsal surfaces. These sharks have a short
terminal mouth, which is armed with small impaling teeth. They also have a
caudal fin, which has a lower lobe that is longer than the upper lobe. Their
pectoral fins extend forward over the ventrally directed gills. The
Pristiophormes have more of an elongated snout, which is saw-like and edged
with slender, needle-sharp lateral teeth. They have two dorsal fins and no
anal fin. They use short transverse mouths and small cuspidate holding teeth
in both jaws. Squaliformes have no anal fin as well, but their snout is not
elongated, but is somewhat long. Many have powerful cutting teeth in both
jaws. In some species these razor sharp teeth are in the lower jaw only and
the upper teeth serve to hold the food. Hexanchiformes have six or seven gill
slits. They are sharks with a single spineless dorsal fin, and an anal fin.
The typical Carcharhiniforme has an elongated snout, a long mouth that reaches
behind the eyes, an anal fin and two spineless dorsal fins. The eyes have
movable, nictitating lower eyelids worked by unique muscles. Teeth vary from
small and cuspidate or flattened to large and bladelike. Carcharhiniformes
have no enlarged rear crushing teeth. Along with this they have a spiral
scroll intestinal valve. A Lamniforme shark has an elongated snout. Most have
long mouths that reach behind the eyes, an anal fin and two spineless dorsal
fins. They also have a ring intestinal valve. The Orectolobiformes have
pig-like snouts and short mouths that in most species are connected to the
nostrils by grooves. There is an anal fin but no fin spines on the two dorsal
fins. They have uniquely formed barbells at the inside edges of the nostrils.
Heterodotiformes are the only living shark that combines fin spines on their
two dorsal fins and anal fin. They only have five-gill slits. In each order
there are specific types of sharks. Each shark belongs to a family with
different species. The Angel shark (Squantiforme) is just one of the many. It
has a single family of about thirteen species. They are all ovoviviparous
livebearers and most do not exceed 1.5 meters. Saw sharks (Pristiophoriformes)
are harmless bottom sharks. They are also a single family but with five
species. They are also ovoviviparous livebearers. Four sharks that belong to
the order Sqauliforme are the Bramble, Dogfish, and Rough sharks. They have
three families with eighty-two species. They too, are ovoviviparous
livebearers. They have more cylindrical bodies. Frilled sharks, Six, and Seven
gill sharks (Hexanchiformes) have two families and five species. Once again
they are also ovoviviparous livebearers. Usually, these guys are found in deep
waters. The Catsharks, Finback Catshark, False Catshark, Barbelled Houndshark,
Weasel, Houndshark, Hammerhead, and Requiem sharks (Carcharhiniformes) have
one hundred and ninety-seven known species. Most of these sharks are known to
be dangerous. They are both oviparous and ovoviviparous livebearers. This is
not the type of shark you would like to have grace you presence. From the
order of Landformes is the Sand, Basking, Goblin, Crocodile, Megamouth,
Thresher, and Mackerel sharks. They come complete with seven families and
fifteen or sixteen species. All of them are ovoviviparous livebearers. These
sharks are found in all seas except Arctic and Antarctic. The last group of
sharks would be the Collared Carpet sharks, Blind, Wobbegongs, Zebra,
Longtailed Carpet Sharks, Whale, and Nurse sharks. They all belong to the
order Orectolobiformes and have seven families and thirty-three species. These
sharks prefer the warmer water and are both ovoviviparous and oviparous
livebearers. Obviously these sharks come in many different sizes and some are
more dangerous than others. At least eighteen species in four families and
nine genera have been implicated in attacks on humans. Obviously a small shark
such as the Pygmy is harmless, but they still must be treated as a predator
especially the bigger ones. The smallest of all sharks is the Pygmy Ribbontail
Catshark, which is about 0.24 meters. Next in line from smallest to largest
would be the Port Jackson Shark, which is about 1.65 meters. After them would
be the Ornate Wobbegong (2.88m) and then the Bull shark (3.4m). The average
sizes go drastically up from there to the Great White shark, which is
incredibly larger, its about 6.4 meters. The two greatest sizes are the
Basking shark (7.8m) and the Whale shark (13.7m). These sharks listed here are
definitely not all the sharks in the world, they were just meant to give an
average range of size for all sharks. Some of the most dangerous sharks range
from about 2 to 8 meters. The Hammerhead, Great White, Tiger, Blue, and the
Bull shark name a few. There are many types of sharks lurking around in
todays ocean. In every one is unique in its own way. Some are different by
size, shape, eating habits, or even the way they breed. Although with all
these differences they are all very similar and that is why the shark is one
of the most amazing creatures of our time. Summary Although sharks belong to
the class Chondrichtyes, there are many different types. Sharks are divided
into 8 major orders. Each order contains 1 or more smaller group. There are
350 or more different kinds of species of sharks. The 8 orders are named the
Squantiformes, Pristiophormes, Squaliformes, Hexanchiformes,
Carcharhiniformes, Lamniformes, Orectolobiformes, and the Heterodotiformes.
These orders group sharks according to certain distinguishing characteristics.
The Angel shark, Saw shark, Frilled shark, Hammerhead shark, Sand shark,
Wobbegongs, and more all belong to a specific order due to their
characteristics. Each one of these sharks come in different shapes and sizes.
Some are more dangerous than others. The more dangerous sharks range from
about 2 to 8 meters. It is obvious that sharks are one of the most amazing
creatures of our time. Among some of the most wasteful reasons to hunt in the
world Id have to say that besides the killing of elephants for their tusks,
this is on top of the list for one of the worst reasons a blue shark is
killed. And sadly enough the United States is one of the top countries to
blame. In Hawaii and Mexico shark finning is very common. The fishermen fish
the sharks take the fins, and throw it back into the water. The fins are
mainly used for fin soup as a status symbol for the Japanese. They eat it for
fin soup. Since the fins contain a high dose of ammonia smell and taste they
must be processed quickly and tossed back into the ocean, and a lot of times
the fish is thrown back into the water alive. Conservations main cause for
concern is the fact that the sharks have a very low reproduction rate. They
dont typically reproduce until the age of twenty-five, and even then they
only produce a few babies. At The rate these fishermen hunt them the sharks
will possibly become endangered in the next few years. This is one of the most
cruelest things Ive ever heard, and not just the killing of them for the
fins, but that fact that they are thrown back into the water without fins. How
is the shark supposed to survive and even swim? That is so cruel. Maybe
someone should cut off fishermens legs and arms, and watch them try to
survive. It probably would probably hard for the fisherman to survive, hed be
a physical vegetable. I hope the United States does something urgently to
control this growing problem before it gets out of hand. The people can do
something about it by obviously not buying shark products but also by writing
letters and sending petitions to congress, we could also spread the word in
other ways in Japan and Hong Kong. But I think if the US stopped the finning,
other countries would probably follow and sales would go down, giving the
sharks a chance to live and breed in peace. Bibliography Works Cited Clark J.
1975. Shark frenzy. Grosset &Dunlap Publishers, New York NY. 106 pp. Clark, E.
1981. Sharks, magnificent and misunderstood. National Geographic 160:138-186
(Aug. 1991) Compagno, L. J. V. 1984. FAO species catalogue. Vol. 4. Sharks of
the world. An annotated and illustrated catalogue of shark species known to
date. Part 2. Carcharhiniformes FAO Fish. Synop. (125) Vol. 4, Pt. 2: 251-655.
Conniff R. 1993. From jaws to laws - now the big bad shark needs protection
from us. Smithsonian 24: 32-43 (Number 2, May1993). Burgess, R. F. 1970. The
sharks. Doubleday &Company, Inc., Garden City NY. 159 pp Word Count: 1252
Word Count: 1720
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