could someone explin ,with examples, the evolution of an aortic arch?
814580
Evolution of the aortic arch system has been one of progressive deletion and substitution, accompanied by a reorientation or rerouting of the blood supply.\nThe greatest changes in the system occurred in the transition from the holoaquatic to the terrestrial habit, with deletion of the first, second, and finally the fifth pairs of arches. Associated with these deletions, and the development of the pulmonary circulation, was reduction and atrophy of the dorsal portion of the\nsixth arches. Subsequently, evolution of the system has resulted in atrophy of one of the radices aortae (left in birds and right in mammals), loss of the left systemic arch in birds, and loss or functional modification of the right systemic arch in mammals.\nStill further changes and deletions in this system are found to occur in the birds.\nOf very common occurrence is reduction or loss of the dorsal portion of either the left or right 3rd aortic arch, accompanied by fusion of the dorsal carotids, anterior to the carotid arch (unicarotid condition). In a few instances, however, both left and right dorsal carotids become reduced to ligamentous vestiges (ligamentiottleyi) and cephalic blood flow is carried by the vertebral and superficialcervical arteries. In such instances, the dorsal portions of both left and right carotid arches become obliterated.\nWith loss of the left systemic arch, the left ductus caroticus loses its posterior connection, and usually becomes functionally modified. In most instances this is followed by a similar disconnection of the right ductus caroticus. The latter, however, frequently retains its connection between the carotid and systemic arches and remains as a patent vessel.\nRecent studies on 810 species and subspecies of birds have revealed the following, rather interesting, fact. In a single specimen of Megapodius freycinet layardi,\nand over 30 specimens of the Trochilidae, both left and right systemic (4th aortic) arches were lacking. In each of these instances, it was apparent that the right ductus caroticus remained as the functional systemic arch which carried the blood\nsupply to the abdominal aorta. Such a condition is not to be regarded as totally unexpected in the course of evolution of the aortic arch system, although it has not, to the writer's knowledge, been reported previously.\nThe particular significance of the occurrence of this reduction in Megapodius and among the Trochilidae cannot be satisfactorily evaluated at this time. It seems to me to be significant that the Trochilidae appear to present a highly uniform occurrence\nin the deletion of the right systemic arch, particularly in view of their rather restricted distribution. Evolution of this family of birds probably centered in\nSouth America, after an earlier origin from the common Apode stock in Antarctica.\nInsular isolation of Megapodius layardi may have been a factor contributing to the evolution and deletion of the right systemic arch in this specimen. It has not, however, been ascertained to what extent this deletion may occur in this species, but\nfurther studies might reveal the expected frequency of occurrence.\nIn conclusion, it may be expected that, in the course of evolution of the aortic arch system of birds, only the proximal or ventral portions of the 3rd aortic (carotid) ancl 6th aortic (pulmonary) arches and the right ductus caroticus will remain as the\nfunctional portions of the embryonic aortic arch system. The major cephalic blood supply will then be carried by the vertebral and superficial cervical arteries, while the blood supply to the abdominal region will be carried by the ductus\ncaroticus and abdominal aorta.
653816
Evolution is a theory.
172396
Check here, it's a nice site for educational materials \nhttp://www.biologycorner.com/images.php
739375
The heart is interesting.  You can also bring in some of the common disorderes of the heart (depending on how long the project is...)\nThe site below will help you off to a good start...:D
629736
This one has been done before, but it's still awesome.\n\nhttp://www.snopes.com/science/dhmo.asp
576461
Simple question, simple answer - Evolution, do some reading.
1069640
for best detailed account for your question,please tune into Discovery Channel.\nThere's this programme about the anatomy of life somethin like that..
333457
How did evolution change over time? You mean...how did evolution evolve?  Heh.  The evolution of evolution.  That's funny.
753264
Coronary arteries (left and right). They branch from the ascending aorta just after its start. These arteries fill with blood during diastole.\nFor more detailed information on their anatomy see:\nhttp://mywebpages.comcast.net/wnor/thoraxlesson4.htm\nhttp://www.clevelandclinic.org/heartcenter/pub/guide/disease/cad/cad_arteries.htm\nhttp://en.wikipedia.org/wiki/Coronary_artery\nhttp://www.hsforum.com/stories/storyReader$1480
239194
I haven't checked to be sure, but theres a site called 'howstuffworks.com' I believe, and it has diagrams and breakdowns of just about anything. Check it out.
1084307
In the example of the flagellum, scientists say that they have no clue how it could put itself together like that, but they will find a way. And same for cilium. And then the giraffe too to and extent. And the human blood clotting system. Or the dolphin.\n\nIf you know the right stuff, you know that it’s impossible. Darwin foresaw this. "If it could be demonstrated that any organ is so complex that it cannot have evolved, my theory would absolutely fall apart." This happened with those organs and animals I listed above.\n\nSo scientists say there will be discoveries in the future. Like Lucy then ape man? Turned out to be the fossil of a human. They say they will find a way.\n\nThere was recently a dinosaur discovered that still had 90% of soft tissue still on it. this couldn't have happened if dinosaurs died out more than 10,000 years ago. Scientists are not - get this- looking for another way for animals to decay and fossilize. That is not science. That's indoctrination.\n\nBut when they look at the things and find more, they will find more complexity, not less. When you look at a small section of a car motor, it looks complex. If you look at a little more, you see more complexity, not less.\n\nthings are too complex to have evolved, but they will still insist that they did. I’m sorry, but doggedly devoting yourself to a theory is not science. you cannot insist that alternatives not be taught in classrooms.\n\nEvolution is not plausible.
812763
Here's one of the easiest examples to see, the gradual sympatric speciation of Globigerinoides trilobus to Globigerinoides bisphericus to Praeorbulina sicana to Orbulina universa (incredibly abundant planktic foraminifera) over several million years. \n\nNow what is your definition of a 'transitional form'? (you have left this very vaguely defined). Most specation is allopatric (occurs in a geographically very restricted subset of the population) and  geologically-rapid (evidenced by observations of evolution and speciation in living populations). The very highest geologic resolution available is in the 1000's of years. But due to the nature of the geologic record, most fossil groups have a much patchier record than this.\n\nAt an inter-species level, there are an overwhelming abundance of examples of 'transitional forms'. The fossil record of hundreds of thousands of species shows copious systematic change from one species/group to the next up the geological column. However, as you are a creationist and are new to asking questions about evolution, I will wait to see what your intellectual honesty and integrity is like before I spend time and effort writing any more detailed answers. Paleontologist.
138775
I found this great website http://www.yourpracticeonline.com.au/showcase.html\n\nIf you scroll right down to the bottom of the page there is a table in white, with a column labelled Heart, then under that click on the Heart Anatomy link. Sorry can't send you direct link - but this opens up a window with a superb anamation you can click around and even move around a 3d model of the heart. Then if you go through the presenation all the main items of the heart are shown.
131055
I'd like to think that you're asking this question with an earnest wish to get good informative answers. If that is the case, I invite you to see the link that Kurdiatcha left, or to do a web search for the term, or else, to read some good Evolution textbooks such as Ridley's "Evolution" or Freeman & Herron's "Evolutionary analysis", or Futuyma, or Stephen Jay Gould if you want something more entertaining.\nIf that is not the case, I'm not bothering anymore *sigh*
541609
An Aorta is a large Artery coming straight off your heart. It is where most your vessels begin to take to the rest of your body. He might have been born with a reduced size (a typical aorta is very large size of 2 fingers) so it takes longer for the body to pump the blood to areas of the body. It is most likely a genetic thing or a fluke that happened during development. I do not know about being born completely with out an aorta.
389680
Hey, iloveicecream103, why don't YOU read a book about science, then talk to us about Genesis, if you still can.\n\nFossil layers show change over time.  The lowest layers have species the least like modern species.  As you progress up the fossil record, each layer is consistently more and more like modern organisms.  Creationists have no explanation for this.  They haven't even bothered trying.\n\nComing up the fossil record, you see forms changing over time.  Clams are preceded by animals like clams, but with their shells united.  Before mammals, mammal-like reptiles.  Before reptiles, reptile-like amphibians.  Before amphibians, amphibian-like fish.  Creationists have no explanation for this either, but they have made a few wasted efforts.\n\nThe transitions evolution expects occur.  Creationists can pretend they aren't *really* transitions, they just *look* like transitions, but that's just like a child yelling "DOES NOT" to win an argument.\n\nCreationists especially need to pretend that no transitions between humans and other apes appear.  They claim that all fossils are obviously human or obviously ape.  However, if you examine the claims of multiple creationists, you'll find they disagree on which are "obviously" which.  If it was so freaking obvious, shouldn't they be able to agree?  At least a little?  Here's a chart:\n\nhttp://www.talkorigins.org/faqs/homs/compare.html\n\nThe only thing obvious about it is that the skulls obviously cannot be considered one or the other and must be seen as transitions by any open-minded person.\n\nThe transitions that evolution doesn't want do not occur.  At no point in the fossil record do we find mammal/birds.  At no point do we find any direct transitions between amphibians and mammals.  We don't find any cat/humans either.  Any of these things, if discovered, would scrap evolutionary theory overnight.  Creationists have yet to explain why God made only species that look like they could have evolved.\n\nEven without any notion of progress or change over time in the fossil record, it's sorting would be an embarrassment to creationists.\n\nScientists respect the fossil record and accept it on its own terms.  If oak trees appear on top of tree ferns, oak trees came after tree ferns.  Creationists need to impose explanations to account for their claims that everything existed together at once, but these do not flow naturally from the evidence.  For instance, they have no explanation for why oak trees are found above tree ferns.\n\nCreationists have three explanations for fossil sorting, none of them works at all.\n\n1.  They like to claim that fossils are sorted by which species could outrun the rising floodwaters (they blame Noah’s' flood for everything they can't explain).  This would mean that moles and sloths can run faster than velociraptors, Oak trees and mangroves can run faster than velociraptors as well.  Velociraptors run at the same speed as tree ferns.  It is also useless for explaining why ichthyosaurs and dolphins are never found together.\n\n2.  They claim that different species occur in different ecological zones, thus would form in different layers.  This fails again.  Mangroves are found in the lowest ecological zone of any flowering plants, but the highest levels of the fossil record.  Oak trees are found high with mangroves, instead of low in the plains.  Tree ferns should be found with oaks.  Moles should be beneath velociraptors again, and ichthyosaurs should, again, be found with dolphins.\n\n3.  They claim that the mechanical action of the flood should sort things.  Well, it should.  Too bad such sorting doesn't look at all like what is seen.  Mangroves sink, for example.  So do waterlogged oaks.  Moles are bullet shaped and would sink faster than light-boned velociraptors.  Dolphins and ichthyosaurs should, again, be found together.\n\nCreationists have lots of explanations for fossil so
1004079
www.howstuffworks.com\nu may find somethin