There are two classes of fishlike creatures in the Chordate Phylum. The first is Chondrichthyes Class, which comprises mainly of Sharks and Rays. The seconds is the common Bony fishes of the class Ostechithyes. The apparent similarities between each speech are only skin deep. They have similar dapperly solely because of convergent evolution and not because of any close evolution connection.
There paired fins can identify class Chrondrichthyes, which comprises namely of sharks and rays, their completely cartilaginous skeletons and biting jaws characteristic of the group. Chrondrichthyes are mainly carnivorous, and the sharks have highly adept senses for vision, olfaction, and hearing. They even posses a system of microscopic organs which can detect changes in water pressure around the shall. Sharks do not possess gills flaps like a fish so a shark must continuously move in order to obtain enough oxygen to survey. The large teeth of a shark are evolutionarily derived from jagged skin scales. Which are apparent on shark’s ancestor’s Placodermi class. The digestion system of a shark contains a “spiral valve'; intestinal system, which increases the surface area and lengthens the time food is digested in the unusually short intestine system of a shark. Sharks sexually reproduce. Unlike a shark, rays have flattened bodies so they can hide themselves in the sand at the bottom of any shallow water area and wait for a meal. Rays also have a whiplike tail for defense and jaws, which it uses to crush mollusks and crustaceans.
Class Osterrichhthyes has the most separate species of any vertebrate class. Unlike their oceanic cosines Bony fish have a skeleton made from calcium phosphate and a slimy skin covered by bony armorlike scales. Fish of the Osterrichhthyes class have gill flaps call an operculum. On the side of there head which have flaps that move while the fish is stationary drawing in water which the fish can convert into oxygen. An unusual characteristic of bony fish is that they can control their density and this control their buoyancy by means of a unique swim bladder. Fish system of flexible fins in another adaptation the fish have made. Unlike sharks bony fishes fertile externally and even in the Osterrichhthyes Class there is great variation in reproductive techniques. There are two distinct subclasses of fishes, Ray finned and fleshy finned, each has a common ancestor. Though divergent evolution the ray finned fish have become a separate class from the fleshy finned.
Scorpaenidae are mostly marine fish,very few found in fresh and brackish water. The family have around around 45 different genera and 380 different species. They are mostly found in the India Ocean and the Pacific Ocean. Most of them lives in coral, tropical reefs and shallow waters, warmer areas. Not all of the family fish lives in the shallow water, small portion of the Scorpaenidae live deep as around 7,000 feet. Just like most of the coral reef fish are, Scorpaenidae have camouflaged body. Their characteristic reflects their name, they have sharp spine that can sting other organisms. Their spine are covered with venomous mucus just like how some other kind of fish are covered with the venomous mucus. Their body are covered with scales. Generally speaking, the Scorpaenidae family fish have different number of spines over the course of the body. Most known type pf Scorpaenidae are lionfish and scorpionfish. Lionfish have preorbital bone with 3 spines, spines and third below the diagonal; , big mouth, end position, oblique fissure. Mandible, vomer and jaw bone with villiform teeth group. Gill openings are wide, tetrabranchiate membranes without the isthmus, pre-opercular margin with 5 spines. Body are ctenoid scales, round head. On the side, there are about eight to nine dorsal fin, fin spines and rays of an anal fin; five to six pectoral fins, they are large, round, and are branched from the upper fin rays. There are about one to five pelvic, sub thoracic; caudal fin rounded truncate. Reef stonefish are extremely camouflaged, they could look exactly like a rock when hiding for predation. The spines of Scorpaenidae are hard and rough, some of their fin spines have poison, can cause serious pain, swells and fatal wounds. Some of ...
The Carcharhinus leucas commonly called the "bull shark" is a very unique shark. The bull shark can live in both salt water and fresh water but is commonly found along the Mississippi River and around Nicaragua. The bull sharks has a very blunt rounded nose giving it a bullish type of appearance thus giving it the name bull shark. The sharks are a dark black to a light grey with a white underbelly. Bull sharks can grow to be about 350 cm long and weigh around 230 kilograms. Bull sharks also tend to have smaller eyes compared to many other sharks which indicates that the bull sharks have limited vision. The bull sharks have triangular teeth like the great white shark (one of the bull sharks cousins). The bulls teeth are heavily serrated and are about 1.5 inches long which makes it easy to tear apart the flesh of their prey.
When the word Shark comes to mind most people think of a monster that feeds on humans and is an enemy of all living beings. Contrary to popular belief less than 10 percent of sharks are known to attack humans unprovoked. Sharks are classified under the class of Chondrichthyes, which is fish that have characteristics of a skeleton made of cartilage, jaws, paired fins, and paired nostrils. The superorders are divided into two groups, which are Batoidea that have rays and their relatives and Selachii, which are sharks. Scientists have found isolated spines, teeth, and scales that appeared 350 to 400 million years ago in the Devonian Period known as "Age of Fishes". Most modern sharks have evolved 100 million years ago when dinosaurs lived on earth. (Matthews, 1989) Sharks have been known to inhabit tropical and temperate seas as well as some cold and polar seas. Migration of sharks is poorly understood due to not all species migrating. And in the species that do migrate the distance may be short or long and is based on availability of the food and environmental cycles. One American biologist Eugenie Clark is the world leader in shark study, she was the first person to learn how sharks behaved in captivity and how well sharks had the ability to understand.
presence of a cartilage skeleton, nine gill slits (turning into five gill slits in sharks, where the first four became the jaw), and fins. Sharks belong to the class Chondrichthyes—a more elaborated organism. Jaws derived from the first four gill slits, spiral valve, and productive fins. The fins are amongst the most important advancements made by the sharks.
PTSD has proven to be unpredictable, and there remain many ambiguous aspects to the disorder. It is thought that perhaps PTSD doesn’t even require experiencing a traumatic event.
Post-Traumatic Stress Disorder is a real mental illness that needs to be taken more seriously. Post-Traumatic Stress Disorder, also known as PTSD, is a mental illness that can develop with people who have experienced a traumatic event in their lives. There are some people that believe PTSD is not a real illness, and that it is an excuse for someone’s behavior. That idea is incorrect. PTSD can severely affect the way a person lives in a real way. It is not a disability that is new to society however it has been recently acknowledged. The Gale Encyclopedia of Psychology states, “Post-traumatic stress disorder has been classified as an anxiety disorder in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders since 1980.” (505).
Sharks use their sensory, hearing and sight senses to detect their prey in the water. They have sensory receptors forming what is referred to as the lateral line. These receptors detect any potential prey and then it moves towards the direction of the stimulus. Electroreception is another mechanism used by sharks to detect their prey. In electroreception, the Shark picks up frail electrical signals produced by muscle contraction of prey that is close.
“PTSD was first brought to public attention in relation to war veterans, but it can result from a variety of traumatic incidents, such as mugging, rape, torture, being kidnapped or held captive, child abuse, car accidents, train wrecks, plane crashes, bombings, or natural disasters such as floods or earthquakes.” (NIMH)
Post-traumatic Stress disorder is defined as a mental illness that involves the exposure to trauma involving death or the threat of death, serious injury, or sexual violence. An event is categorized as traumatic when it is frightening, overwhelming and causes a lot of distress. A traumatic event can range anywhere from crimes to wars and are often unexpected. The difference between PTSD and a normal response to trauma is the duration of the symptoms someone experiences after the event. A normal response to trauma includes the same symptoms as PTSD but lasts between several days and several weeks, but they eventually subside. It is not out of the ordinary that people experience these problems; it would be strange if they didn’t. Nevertheless, a normal response to trauma escalates to PTSD when someone gets stuck in that state for an extended period of time. The symptoms don’t decrease and individuals progressively begin to feel worse as each day passes.
Mojetta wrote about prehistoric sharks, and the history of these creatures. According to Angelo Mojetta, author of Sharks, Cladoselache genus, one of the first prehistoric sharks, was buried in sediment that kept it preserved. Unlike other sharks, Cladoselache genus had a circle of tiny plates around it’s eyes for protection against it’s victim’s attempts to fight back. These sharks lived over 400 million years ago. Sharks of the past could mostly be identified by their teeth, because shark’s bodies are made of cartilage. Another shark that was focused on was called, Stethacanthus. This shark had a very unique look. Stethacanthus had a brush like decoration on the top of it’s head, and an extra fin like part that had the same bristle like decorations on it. These characteristics were thought to be used as suction cups, to hitch rides from larger fish. One of the most famous sharks that looks like an over...
The DSM-IV-TR requires six criteria for a diagnosis of PTSD. Criterion A defines the traumatic event, including any specifics relating to the event itself (Criterion A1) and the response to the event (Criterion A2). Criterion B refers to symptoms of re-experiencing the trauma, criterion C refers to the avoidance of reminders and numbing of general responsiveness to the event and criterion D refers to symptoms persistent by increased hyper arousal. Criterion E involves symptoms being present for longer than 1 month, and criterion F involves disturbances that cause distress and impairment to areas of functioning (Diagnostic and Statistical Manual of Mental Disorders 2000). It is classified as acute if symptoms last less than three months and if symptoms present beyond 3 mo...
We have been allowing cell phones to impact our lives in negative ways. Our everyday life changes every day because of these cell phones and how we use them. I have noticed in everyone’s life, including mine, that it is hindering us socially and physically. My biggest concern is the negative impact it is having on our education and students allowing them to get in the way of their education. We need to get a hold on these cell phones before it gets any more out of hand, but I think it is too
On average they weigh 4,000-7,000 pounds and grow approximately 16-20 feet long ( Great white sharks 1). < commentary needed>Great Whites are the apex predator of the ocean containing 300 serrated teeth and highly-developed senses to hunt prey. Sharks have a great senses of smell, the Great White can smell a drop of blood thousand of miles away. They’re hearing is very powerful , being able to hear the vibrations of prey distances of about 800 ft away and find the exact location through ‘ear stone’( Great white 3). A shark 's sense of hearing truly shows their uniqueness as an apex predator. In addition to great hearing they’re known to have great sight by being able to see up to 50ft away and transition into seeing in light and dark. Additionally sharks have a lateral line on their back that reaches from the front to the back tail, allowing
Most people think that sharks are large, fast-swimmers, and savage predators. This is true of some species and groups should be interested of the appealing aspects of biology found within it: all sharks have an excellent sense of smell; some can detect electrical discharges; some sharks give birth to one of the