do salps have skeletons? and any other interesting facts do they have back bones?
98783
Salps are gelatinous, mostly transparent, and cylindrically shaped. They vary in size from a few millimetres at birth  up to about 10cm. One species is known to reach a few meters. Individual salps form a colony during the sexual phase of their lifecycle. The colony is long and chain-like in some species and  wheel-like in others.\nSalps filter food particles by pumping seawater in the mouth opening and out the atrial opening using muscle contractions. This pumping action gives animals propulsion, too so swimming and feeding occur at the same time.\nSalps have a complex lifecycle alternating between a sexual and asexual form. Sexual forms are called aggregates because they form a colony while asexual forms are solitary. All females have one or two eggs when released by a solitary parent. Mating occurs with larger male aggregates and embryos grow inside an aggregate body by being nurtured through a placenta. When embryos mature, they are released and the mother aggregate becomes male. Released embryos grow to be mature solitaries that asexually reproduce ‘stolons’ - buds of young aggregates.\nPretty wierd, huh? They look like jelly fish. And no, no backbones...!!
206614
some animals were them on the outsied insects and lobsters.\ninvertabreas dont have a spine and some dont have any bones!
563715
er, here we go (and this is straight off the top of my head)\n\nNo skeleton (endo or exo)means that they cannot self support. (neg)\nNo real means of self propulsion (neg)\nMostly translucent (pos) (from a prey point of view)\nSome have stingers (pos) for food capture and defense\n\nand thats all i've got. It's been too many years since school. sorry
570457
Mollusks are triploblastic protostomes. The principal body cavity is a blood-filled hemocoel. It is unknown whether they have a true coelom (eucoelom); any coelomic cavities have been reduced to vestiges around the hearts, gonads, and metanephridia (kidney-like organs). The body is often divided into a head, with eyes or tentacles, a muscular foot and a visceral mass housing the organs.\n\nMollusks have a mantle, which is a fold of the outer skin lining the shell, and a muscular foot that is used for motion. Many mollusks have their mantle produce a calcium carbonate external shell and their gill extracts oxygen from the water and disposes waste. All species of the phylum Mollusca have a complete digestive tract that starts from the mouth to the anus. Many have a feeding structure, the radula, mostly composed of chitin. Radulae are diverse within the Mollusca, ranging from structures used to scrape algae off rocks, to the harpoon-like structures of cone snails. Cephalopods (squid, octopuses, cuttlefish) also possess a chitinous beak. Unlike the closely related annelids, mollusks lack body segmentation.\n\nDevelopment passes through one or two trochophore stages, one of which (the veliger) is unique to the group. These suggest a close relationship between the mollusks and various other protostomes, notably the Annelids.\n\nMollusk fossils are some of the best known and are found from the Cambrian onwards.
525521
Female Reproductive System.\n\nDescription:\nThis is the human's reproductive system, that is capable of producing a new being to the world. This is situated in the female gender of any species. (But we do find certain exceptions like, Sea Horses, where the female sea-horse simply produces the eggs, yet hands them over to the male sea-horse to take care of! mostly mistaken to believe that male sea-horses do have a reproductive system.) Its the only natural way of reproducing a specific being to the world.(Their are other ways, to reproduce species, in a lab i.e. cloning, tube.) \n\nBenifit:\nReproduction of a specific specie would keep them away from the Red-Data-Book, where all the endangered species are listed.\n\nThis is a very basic explanation.\n\nHope it is helpful!\nGood Luck!
683699
yes, he's right.  A mid sagittal crest.  It will be more pronounced on males than females due to more masculinizing hormone (testosterone) in males than females.  \nMy male cat's CREST is quite pronounced and female is negligable.  After the muscles come off skulls-bones after death, one can see the lines of origins and insertions of most muscles.  The more active a person-animal was with their muscles, the more pronounced these crests and markings will be.  Bone develoment (buildup) occurs all throughout life and depends on the amount of STRESS the muscles place on the bones. THIS IS TRUE IN ANIMALS AND HUMANS.
209657
The debate still continues as to whether we do or do not, or, did or did not. \n\nEvolutionists believe we did and still do in the shape of a 'vestigial organ'; i.e. the coccyx (tail bone). A 'vestigial organ' is an organs that is supposed to represent useless remnants of what were once functional and useful organs in our primitive ancestors. Those who disagree claim that this tail bone is nothing of the sort and is a necessary part of present human anatomy and was never a tail in the true sense and definition.\n\nExamples:\n\nThis from Wikipaedia:\n\nHuman embryos have a tail that measures about one-sixth of the size of the embryo itself. As the embryo develops into a fetus, the tail is absorbed by the growing body. Infrequently, a child is born with a "soft tail", which contains no vertebrae, but only blood vessels, muscles, and nerves. Modern procedures allow doctors to eliminate the tail at delivery. The longest human tail on record belonged to a twelve-year-old boy living in what was then French Indochina, which measured nine inches (229 mm).\n\nThis from the MAFC:\n\nAll true tails have bones in them that are a posterior extension of the vertebral column. Also, all true tails have muscles associated with their vertebrae which permit some movement of the tail. Ledley conceded that there has never been a single documented case of an animal tail lacking these distinctive features, nor has there been a single case of a human caudal appendage having any of these features. In fact, the caudal appendage Ledley described is merely a fatty outgrowth of skin that wasn't located in the right place on the back to be a tail!\n\nAh - the richness of human debate.
1083910
Catfish don't have shells behind their eyes. A catfish skull is just the internalized version of the armoured plating that was present on the outside of their ancestors skulls.
982526
That depends upon the body.  Not everyone weighs the same.  Skeletons also vary.  Then there is the question, "Were you referring to human bodies"?  Different animals have differing bone structures.  Most birds have very light skeletons by comparison to other animals.
152552
I hope that's not a question one of your teachers made. That would be depressing. \nKurdiatcha is right :)\nBut technically speaking, adult sea squirts don't have spinal cords, a lancelet would be a better example. \nWow, I've just done a quick search and there's a wikipedia article (http://en.wikipedia.org/wiki/Tunicata) stating that the notochord is a "primitive spinal cord". Maybe my English vocabulary is wrong, but they seem to have forgotten that primitive chordates have both a notochord and a spinal cord.
1130237
Yes.  All three are homologous structures.  Bones in one map to equivalent bones in the other, although varying in size and shape.  \n\n(BTW, by 'sea flipper', this is referring to flippers in aquatic mammals like seals and sea-lions, and even dolphins and whales.  The fins of fish are *not* homologous structures.)\n\nAnd to pjfrmtw, arms and bird wings are homologous structures (not just analogous, or the result of convergent evolution), as they are structures found in a common ancestor between mammals and birds, namely, early reptiles.
20143
Hi,\n\nAccording to this site:\nhttp://www.tonmo.com/articles/articles.php\n\nOctopus has three hearts.\n\nQuote:\n"Does an octopus really have three hearts?\n...and how do they breathe? I've been asked these questions on a few occasions. \n\nThe fact is that octopuses do possess three hearts. Each has an important role in fueling the impressive respiration and circulatory system of the octopus."
1115360
The simple answer is, of course, different anatomical adaptations. Since water helps support the whales mass, their skeletons are relatively light compared to a land animal's. The dinosaurs had made many adaptations to their weight -- just as elephants, hippos and rhinos have.\n\nThat said, a small fall for a creature of large mass is likely to do internal damage in a way that never happens for small animals.
264009
animals with no backbone are known collectively as invertebrates.\nhope this is some help as your question was vague.
801430
There Sach's organ has a stack of electroplaques, which acts somewhat as a stack of battery plates. There evolutionary history is not know to me.
648453
Here's the thing: I'm not an expert on fetal anatomy, but human fetuses do not have gills.  They do have tails for a few weeks, appearing around the 4th week and dispearing around the 8th.  They also have regions that are homolgous to those that develop into gills in aquatic organisms, but will form the throat of the human fetus.\n\nThe gill and tail myth was created by a man named Haeckel.  Now, Haeckel actually (whatever creationists may say) did have some good ideas, but he was a very bad scientist and had an unfortunate tendancy, especially in the later part of his career, to exagerate and even completely fabricate morphological features of embryos.\n\nHOWEVER, there _is_ an association between fetal development and evolutionary lineage.  It's just a bit more subtle than Haeckel claimed.  While embryos don't go through stages that ressemble the adult forms of their ancestors, the is a distinct correlation between the age at which the morphology of embryos of different species diverges and the evolutionary relationship between those species.  For example, human embryos and chimp embryos look really similar for a lot longer than human embryos and snake embryos.  But human and snake embryos look similar to each other long after they have completely diverged from the development of, say, a sea urchin.\n\nYour point about gills and tails isn't very accurate, and the actual connection between evolution and development is not very accesable to the non-scientist, but there is plenty of evidence for evolution that doesn't take a PhD to understand.  Here are a few points that I hope will help you next time you want to defend the theory of evolution:\n\n\n1. Vestigial structures\n\nOne example of a vestigial structure in humans is the appendix. It has no function. Removing it is harmful only in so far as any surgery is associated with certain risks (so I wouldn't have it removed just for fun, but it's because of the surgery not the absence of the appendix). An appendix is found in several mammals. In humans it is small and has no known function. In rabbits and many other herbivores it is large and is used in the digestion of cellulose.\n\nAnother example of a vestigial structure is the hipbones of snakes. Snakes evolved from quadrupeds, and some species still retain not on pelvises, but tiny protrusions of bone in a location that corresponds to the location of the legs in other quadrupeds.\n\n2. Microevolution can be observed in both a controlled laboratory setting and in nature.\n\nCreationists will tell you that microevolution does not prove macroevolution.  This is true.  However, it does provide evidence that macroevolution may be possible. Taken in the context of the other evidence for evolution, microevolution provides a mechanism by which macroevolution could occur. On its own, it doesn't prove that macroevolution occurs, but it does suggest that it is possible.\n\n3. The fossil record.\n\nAlthough the fossil record does not provide a “complete” record as fossils form only under certain conditions, it does show a gradual change in the morphology of species as well as numerous extinct species.  There are a number of methods used to date fossils, and the time period from which a fossil comes can be determined with reasonable accuracy.\n\n4. Imperfect structures (the blind spot of the mammalian eye, for example).\n\nI want to mention the bind-spot of the mammalian eye specifically because creationists often hold up the human eye up as an example of something that is too perfect to occur by "chance" (i.e. as the result of the natural selection of beneficial changes among random mutations).\n\nThere are also numerous examples where the morphology of a species is constrained by similar patterns in its ancestors (quadrupeds, vertebrates, etc.).\n\n5. Developmental biology reflects evolutionary lineage.\n\nCreationists like to bring up a man named Haeckel in response to this argument.
638082
yes and i just learned in diversity lecture that the shell forms from the rib cage. the ribs have expanded outward and fused together, the limb girdles(shoulder blades) are inside the rib cage. now that is cool. i am not sure but i don't think they are soft at birth maybe the outer layer of skin and scales are soft but i doubt the bones are.