are sharks vertebrates?
93884
yep, not jellyfish, are they?
6640
The first three are mammals. The shark is a fish. To know whether "fishlike" sea denizens are fish or not, the rule is: if the tail is vertical and moves from left to right (like the shark) then it's a fish; if the tail is horizontal and moves up and down to propel the animal, it's a mammal (like the whale).
32854
Fishes, as all other vertebrates, have closed circulatory systems; they have a single blood circuit in which the heart pumps the blood toward the gills where it picks up oxygen, and is then distributed to the body. However, our (human) anatomy is very derived with respect to aquatic pisciform vertebrates. In fishes the circulatory system is very symmetrical and more metameric. The best place to look is the gill area, where the major vessels occur. The heart, which looks like an elongated bulb, is situated ventrally right behind the gill basket. The ventral aorta is the major vessel extending forward below the gills, and emits branches to each functional gill. Once they go through the gill filaments, these vessels reunite dorsally and form the dorsal aorta (paired, then joined). Other vessels are difficult to observe as they usually collapse in dead materials, but if you have fresh large specimens you could try injecting a colored rubber solution (VERY carefully) inside the largest vessel you can find and if the walls are not broken, you will get an internal cast of part of the system. \nAlso look for the dorsal longitudinal vessels that are really close to the vertebrae, passing through the haemal arches.
31274
Most, if not all mammals are vertebrates.  That simply means that they have a backbone or a spinal column.  An example of an invertebrate would be an octupus.  Hope this clears it up a bit!
667467
ANY KIND OF ANIMAL WITH GILLS, SHARKS, FISH, ETC. I GUESS..
675249
Elasmobranchs (sharks, skates, and rays) indeed have an interesting sensory physiology enabling them to sense a variety of physical stimuli.  But fear is not one of them. That said, it is true though that fear may be associated with either the release of particular chemical compounds, but far more importantly and likey in regards to your question, with particular behavior.  And in that sharks are not very different from any other predator.\n\nThe sense of smell is indeed very well established in almost all elasmobranchs; if you ever take a look at a shark's brain note the extremely large bulbi olfactorii, the areas of the brain where smell is first analyzed.  The sentivity of shark noses for blood is often emphasized, but you must not imagine sharks to be "swimming noses."  Rather, they rely on different senses for different environmental conditions, prey, etc. The priority assigned to either one of the possible sensory modes is largely dependent on the life-style of the animal.  Given that there are over 400 different species, there are a few variations.\n\nLike many other aquatic animals (e.g., teleosts, but also amphibians) sharks rely on their lateral line organ for detecting objects in greater distances.  The lateral line organ is a tiny canal running along the side of the animal underneath the skin.  it is open to the environment through a set of pores, through which the shark can sense pressure differences in the water, as they are being produced for example by a fish in distress.  This can of course be misunderstood as "smelling fear," when in fact it is more like "sensing the panicked movements of a potential prey."\n\nThe electromagnetic sense of elasmobranchs is perhaps most amazing from a human point of view, since it is so very different from anything we have.  All elasmobranchs have Ampullae of Lorentzi, with which the animals can indeed sense bioelectric fields.  These organs are so sensitive that a dogfish can sense the bioelectric field induced by the beating heart of a flounder covered by sand.  Sharks also use this organ for a magnetic compass.  By swimming through the earth's magnetic field, a shark will induce an electric current that will either run from its back to its belly (when the animal swims in an eastern direction), or from its belly to its back (in western direction).  with its own electromagnetic sensores, the animal can sense the induced electric current and its direction and can thus orient itself along the magnetic field of the earth.  Again, very sexy and very helpful, but no detector of fear!\n\nNow, some sharks use their eyes when they hunt prey, and this may an important point in regards to your question.  Great white sharks (Carcharodon carcharias) often attack their prey (e.g., seals) from far below, orienting themselves visually in their attack and going for the tell-tale silhoutte of the pinniped.  Some sharks, like the lemon shark (Negaprion brevirostris), have an interesting eye, where the sensitivity of the retina changes from light of one particular wavelength during day time to one of a different wavelength during night time.  This Purkinje-shift allows the animals to see optimally during day and night.  Now, many animals (or humans) in distress show a particular behavior.  Sometimes, a flight response is what is initiated when faced with a predator.  This behavior can signal the shark that the fleeing animal (or human) is afraid and therefore not a danger but rather a potential prey.  Consequently, fear in humans that cause a flight response may cause sharks to respond accordingly.  This may also be misunderstood as "smelling fear."  This, by the way, is the same kind of behavior a cougar, dog, or bear will dislay.\n\nThat said, there is always the possibility that during fear a human may release certain chemical compounds that the shark can smell.  But I doubt that this is something really significant in a real-life encounter.\n\n
722053
The coelom is the true body cavity, coelomates are characterized by having a body cavity lined with mesoderm.  \n\nSharks (Chondrichthyes) are coelomates.
471078
There are sharks in all seas and oceans aaround the world. \n\nThere are many species of sharks found in the Mediterranean, especially in the western and central Med - including Hammerheads and Great Whites. Unfortunately the numbers of these sharks, of all sharks in the med, are in great decline and in many areas the numbers are close to non-existent. The culprit for this is commercial fishing (for blackfinn tuna and swordfish - both as a result of being caught in netsAND having their natural food sources depleted, in some cases to extinction - bluefin tuna became extinct in the Med in the 1940's)and, ironically enough, tourism. Especilly around Croatia in the late 90's there were several 'Jaws Tours'operating. The 'chumming' undertaken to attract sharks obviously attracted sharks into tourist areas which resulted in the culling of many, many sharks so as not to endanger tourism!\n\nSo, yes, there are sharks in the Med but I wouldn't be put of swimming in the Med as shark attacks here are almost non existent. Between 1508 and 2004 therewere a total of 38 shark attacks in European/Mediterranean waters. 18 of which were fatal with the last reported fatal shark attack being in 1984.  \n\nBut please get your friend to put the possibility of shark attack into persective. WORLDWIDE shark attacks between 1508 and 2004 totalled 1,986 of which 486 were fatal - in almost 500 YEARS! More people have been killed by deers running into their cars than by sharks!
631008
Sharks are boneless fish, so very primitive evolutionarily-they harken back a few hundred million years, without very much change- I seriously doubt, both because they are so primitive and havent changed in so long, that they have any remaining vestigial structures.  Generally vestigial structures come from an animal that has evolved from a quite different precursor-sharks are very close to the very first fish that evolved, thus they probably havent had to shed any organs or bones that arent useful.\nRibs? How is that vestigial?  They use their ribs for structural support, just like all fish...
495054
Great white sharks have been found along the coastlines of California to Alaska, the east coast of the USA and most of the Gulf coast, Hawaii, most of South America, South Africa, Australia (except the north coast), New Zealand, the Mediterranean Sea, West Africa to Scandinavia, Japan, and the eastern coastline of China and southern Russia.
961311
Basking sharks and whale sharks are fish that eat plankton that a killer whale may try to eat. Killer whales eat gray whales, minke whales, blue whales, and sperm whales but they are all mammals and not fish.
267950
The mammals are the class of vertebrate animals characterized by the presence of mammary glands, which in females produce milk for the nourishment of young; the presence of hair or fur; and endothermic or "warm-blooded" bodies. The brain regulates endothermic and circulatory systems, including a four-chambered heart. Mammals encompass some 5,500 species, distributed in about 1,200 genera, 152 families and up to 46 orders, though this varies depending on the classification scheme adopted.\n\nPhylogenetically, Mammalia is defined as all of the descendants of the most recent common ancestor of monotremes (e.g., echidnas and platypuses) and therian mammals (marsupials and placentals).\n\nWhile most mammals give birth to live young, there are a few mammals (the monotremes) that lay eggs. Live birth also occurs in a variety of non-mammalian species, such as guppies and hammerhead sharks; thus it is not a distinguishing characteristic of mammals. Although all mammals are endothermic, so are birds, and so this too is not a defining feature.\n\nA characteristic of mammals is that they have mammary glands, a defining feature present only in mammals. The monotremes branched from other mammals early on, and do not have nipples, but they do have mammary glands.\n\nMammals have three bones in each ear and one (the dentary) on each side of the lower jaw; all other vertebrates with ears have one bone (the stapes) in the ear and at least three on each side of the jaw. A group of therapsids called cynodonts had three bones in the jaw, but the main jaw joint was the dentary and the other bones conducted sound. The extra jaw bones of other vertebrates are thought to be homologous with the malleus and incus of the mammal ear.\n\nAll mammalian brains possess a neocortex. This brain region is unique to mammals.\n\nMammals have integumentary systems made up of three layers: the outermost epidermis, the dermis, and the hypodermis. This characteristic is not unique to mammals, but is found in all vertebrates\n\nThe epidermis is typically ten to thirty cells thick, its main function being to provide a waterproof layer. Its outermost cells are constantly lost; its bottommost cells are constantly dividing and pushing upward. The middle layer, the dermis, is fifteen to forty times thicker than the epidermis. The dermis is made up of many components such as bony structures and blood vessels. The hypodermis is made up of adipose tissue. Its job is to store lipids, and to provide cushioning and insulation. The thickness of this layer varies widely from species to species.\n\nMost mammals are terrestrial, but a number are aquatic, including sirenia (manatees and dugongs) and the cetaceans (dolphins and whales). Whales are the largest of all animals. There are semi-aquatic species such as seals which come to land to breed but spend the majority of the time in water.\n\nTrue flight has evolved only once in mammals, the bats; mammals such as flying squirrels and flying lemurs are actually gliding animals.\n\nNo mammals have hair naturally blue or green in colour. Some cetaceans, along with the mandrills appear to have shades of blue skin. Many mammals are indicated as having blue hair or fur, but in all cases, it will be found to be a shade of grey. The two-toed sloth can seem to have green fur, however, this colour is caused by algae growths.\n\n[edit]\nOrigins\nMammals belong among the amniotes, and in particular to a group called the synapsids, distinguished by the shape of their skulls, in particular the presence of a single hole on each side where jaw muscles attach, called temporal fenestra. In comparison, dinosaurs, birds, and most reptiles are diapsids, with two temporal fenestrae on each side of the skull; and turtles, with no temporal fenestra, are anapsids.\n\nFrom early synapsids came the first mammal precursors, therapsids, and more specifically the eucynodonts, 220 million years ago (mya) during the Triassic period.\n\nPre-mammalian ears b
974358
lizards can regenerate tails\nnewts and salamanders can regenerate\n\nPlanarians are flat worms. If cut into pieces, each piece can grow into a new worm.\n\nSea cucumbers have bodies that can grow to be three feet long. If cut into pieces, each one can become a new sea cucumber.\n\nSharks continually replace lost teeth. A shark may grow 24,000 teeth in a lifetime.\n\nSpiders can regrow missing legs or parts of legs.\n\nStarfish that lose arms can grow new ones; sometimes an entire animal can grow from a single lost arm.
552640
Super class of jawless vertebrates--Agnatha\n\nIt is further classified into 2 classes--\n\n1)Ostracodermi---extinct\n2)Cyclostomata -- the circular mouthed fishes. eg. Myxine(Hagfish) & Petromyzon(Lamprey).
855593
I would look here for your answer and/or a link that could get you your answer http://en.wikipedia.org/wiki/Vertebrate\n\nGood Luck!!!
23799
A Great White Shark will WIN because crocs can't swim as fast and sharks got way SHARPER teeth. There you go. SHARKS RULE THE SEA. But if its a land fight then OF course. The shark will be dead before you know it.
400729
We have only three: photoreception (vision), chemoreception (smell and taste), and mechanoreception (touch and hearing). Similarly, sharks do not have 13 senses, they have four: the three we have plus electroreception.\n\nElectroreception is found in many marine and freshwater fishes, several amphibians, as well as a few mammals. These electrosensitive mammals include the 'primitive' egg-laying monotremes - the Platypus (Ornithorhynchus anatinus), the Short-Beaked (Tachyglossus aculeatus) and Long-Beaked (Zaglossus bruijni) Echidnas - and at least one 'higher' placental mammal, the Star-Nosed Mole (Condylura cristata). All vertebrates share a common ancestor. Since the ability to sense electric fields has re-appeared several times in discrete vertebrate lineages, electroreception must be a very ancient ability.