prehistoric and current animal life

They aren't even close to being the same thing. I have no time to go into details but feel free to Google pictures of crocs and tyrranosaurus rexes and you'll see that immediately for yourself.

Animal transformers. It would make quite a cartoon series for TV.

T rexes and crocodiles are of two separate orders of Diapsid reptiles .Dinos were probably warm blooded and were derived from a common ancestor back in the PErmian,but )since we dont have any dino DNA (yet) we always assume the close kinship of living reptiles with dinos. Dinos were closer to birds than modern reptiles.
The classification used to have dinos and "ruling reptiles" trogether and then broke them off at a "Superorder" where Archeosaurs DID include modern crocodilians . Actually that (classification made more sense to me )
CLASS REPTILIA
Subclass ANAPSIDA (includes modern turtles and cotylosaurs)
Subclass Synapsida (mammal like reptiles of the PErmian)
Subclass Parapsida (Icthyosaurs)
Subclass Eurapsida ("paddle footed" marine reptiles
Subclass Diapsida (snakes lizards, crocs and dinosaurs)
SUPERORDER Lepidosauria (rhyncocephalians, snakes and lizards)

SUPERORDER Archosauria
ORDER Thecodontia-(phytosaurs)
ORDER Crocodilia
ORDER Pterosauria (ancient flying reptiles)
ORDER SAUrischia (saurischian dinosaurs)
ORDER Ornithishia (duck bills and stegosaurs )

this system has changed a bit since it was a standard used by Colbert (not Stephen) and was adopted by convention in the 1960's. Later classification , by genetic inferences have rearranged these classes, subclasses, and superorders around a bit but not that it would confuse. Now snakes and lizards all belong to the Superorder LEPIDOSAURS. It gets a bit confusing because from there(upwards) the entire classification of all reptiles gets really split up into many small subcatagories that only mean something to vertebrate paleontologists.

Theres a new system of alphanumeric classification (as opposed to this Linnean system) where everything is first ordered about by genetic inference from modern forms. Then the left over fossil forms are being put within these groups. (ITs not done yet)

I think whatll happen is that there will be a transitional form in the class for "Bird like dinosaurs and birds themselves"

Animals don't really "De-evolve" into more primitive forms. Even though reptiles and dinosaurs have a common ancestor (as do all living things), they have diverged quite extensively and are no longer closely related.

Just out of curiosity, what are the similarities you say you see between T-Rex's and modern Crocodiles?

thank's rosboorne979, just that they are meat eaters and have small front arms and a huge tail and hind leg's i guess i could imagine seeing them uprite and more larger in size and although it may take along time for that to occur i just felt they might adapt to a catoclismic event as i had said earlier , i relate the idea to reptiles as well , note the differences between land reptiles and water adapted reptiles and insects . I really only have a view on this in some way that the creatures here now might have been .

While it's within the realm of possibility that animals might adapt to cataclysm in such a way as to seem to regress in evolutionary form, the reality is that we have extensive fossil and genetic evidence which prove that T-Rex and Crocodilians diverged from a common ancestor millions of years ago.

The similarities you mentioned are very rudimentary in comparison with the detailed information we have on internal bone structure and a host of other anatomical features from these two lines. The T-Rex's are part of an entire line of dinosaurs called theropods which were "Bird Hipped" dinosaurs. That Bird Hip bone structure is substantially different from anything in you will find in crocodiles now or in the past.

I seem to recall reading that some marine mammals had evolved on land and returned to the sea. Can't even recall the source, but either dolfins or whales, or both. Anyway, I'm not sure you could call this deevolution, either, but it is worth a passing thought.

Hi Roger, you are correct, it's not "De-Evolution", it's evolution toward a different form. Just because something returns to the sea doesn't mean it's de-evolving.

However, it's possible that something might evolve toward a form which resembles something more primitive.

Doorsmad, have you considered the similarities between T-Rex (a theropod dinosaur) and birds?

Theropod:


RoadRunner:

The wings on primitive birds still retain "clawlike" bone structures.

MicroRaptor Gui


These little raptors might not have been able to fly, but they could probably glide quite effectively.

A quick history of Tree Climbing Dinosaurs

Please excuse my observation's as i really dont have anything to back up my theory , it just seem's that many of the related cousins to dinasaurs are still here . As you look araund at our wildlife it isn't hard to try and connect thing together abit more , yes thing's are extinct but the jurasic period meant that the beast's and reptiles and so forth had time to reach there size before man and mother nature intervened . All its we had to go by were bones in many instances for information i still think if our present animal life were left unattended for 30 million years then we may find destinct connections that may support my view .

here some findings in relation to birds and dino's , however the simularities betwen crocks and dino's in the anoyomy of repruduction and egg laying are connected journal Proceedings of the Royal Society B.
Lingham-Soliar and colleagues' results support the arguments of a small but highly vocal group of scientists who say there's no evidence of dinosaurs ever having feathers.
"The existence of protofeathers in these dinosaurs was considered critical evidence that birds were derived from dinosaurs," said study co-author Alan Feduccia, a bird evolution expert at the University of North Carolina at Chapel Hill. "What we have shown is that there's absolutely no evidence whatsoever that protofeathers existed in dinosaurs, period."
But the majority of scientists in the field are unconvinced.

"These people have been flogging the same horse for a long time," said Kevin Padian, curator of the University of California Museum of Paleontology. "It is appalling that Proceedings B chose to publish this nonsense."
Current theory says that over time theropods developed plant-eating habits, grew feathers to keep warm, and took to the trees for safety. But skeptics of this theory argue that birds evolved earlier from a common ancestor with dinosaurs, and that dinos never had feathers. For the new study, researchers looked at a recently discovered Sinosauropteryx specimen also found in Liaoning.
"The peripheral dorsal structures are the remains of fiber reinforcement of the frill" that extended from the head to the tip of the tail of the dinosaur, said lead author Lingham-Soliar. "Their regular nature and straightness defies the notion of them being soft pliable structures [like feathers] but rather high-tensile fibers such as collagen."
The fibers show a striking similarity to the collagen found on the skin of sharks and reptiles today, the authors say. And without protofeathers in Sinosauropteryx, the authors argue, the theory that feathers first evolved in dinosaurs"not for flight but for insulation"falls flat.
David Unwin, a vertebrate paleontologist at the University of Leicester in England, considers himself neutral on the issue. He said that scientists need to better understand how soft tissues in well-preserved dinosaurs are actually fossilized. But the new study falls short because it relies only on microscopic analysis, with no additional CAT scans or chemical tests, he said. "They merely looked at the tissues and said, Oh, they're straight and well organized … it must be collagen," Unwin said. In some cases, he said, the fibers do look like collagen. "But what they didn't draw attention to is that there are other tissues in there that don't look like collagen and might be protofeathers."
And what about the many other dinosaurs that appear to have been feathered? Feduccia, the study co-author, says these creatures are actually descendants of birds that lost their ability to fly. "When they become flightless, they superficially resemble small dinosaurs," he said.

Minority View
Storrs Olson, the curator of birds at the Smithsonian Institution's National Museum of Natural History, has been a vocal critic of the theory that modern birds evolved from dinosaurs. "The whole notion of feathered dinosaurs is a myth that has been created by ideologues bent on perpetuating the birds-are-dinosaurs theory in the face of all contrary evidence," he said.
National Geographic magazine and other media have heavily publicized stories about feathered dinosaurs. But contrarian views struggle to get heard, Feduccia said.
"One of the primary arguments used to deflect our view is that we are a fringe group," he said. "But if science operates by a majority view, we're in serious trouble. "We are dealing here basically with a faith-based science where the contrarian view is silenced to a large extent by the popular press," he added.
The University of Leicester's Unwin said that science benefits from opposing views, "because it keeps the people who are arguing for a dinosaur origin for birds on their toes."
"One way the [latest] paper may be significant, though, is that it suggests that the story of the origin of feathers may not be quite as simple as we would like to have it."



The following is an E-mail exchange between myself and Zachary Armstrong. Zach starts off (bold font):



Dear Mr. Pitman,

Hi, my name is Zach, and I find your website very interesting and helpful,
but I do have some problems with your article on dinosaur feathers. I do not
think that the feather impressions on the dinosaurs are collagen fibers for
several reasons.

First, when the Confuciusornis specimens were found in the Liaonin

He's wrong. Many raptors show clear evidence of feathers. In addition, feathers are not the only (or even the primary) piece of evidence linking birds to theropods.

Perhaps the information you have quoted is out of date. The evidence for feathers on dinosaurs has become conclusive over the last few years.

I believe that i read many, many years ago that the internal structure of the bones of dinosaurs more closely resembles that of birds than of contemporary reptilian species.

Correct.

This artical from Aust, 2008 was interesting.
http://www.livescience.com/animals/080528-fossil-embryo.html

Oldest Embryo Fossil Found
By Jeanna Bryner, Senior Writer
posted: 28 May 2008 01:00 pm ET

An armored fish was about to become a mom some 380 million years ago. Though the primitive fish perished, its fossilized remains remarkably reveal an embryo and umbilical cord inside the soon-to-be mother's body.

The discovery marks the oldest evidence of an animal giving live birth, pushing the known record of such reproduction back by some 200 million years. It also supports the idea that internal fertilization in vertebrates (animals with backbones) originated in a group of primitive fish.

The ornithischian clan of dinos has not evidenced feather in any fashion till recent fossils from near Lianing have shown up. (If these fossils are not fakes they represent a line of "Bird hipped" dinos from the Valanginian Period of the Cretaceous, the fossil is of a species called Tianyulong confusciusi. The "LIZARD HIPPED" dinosaurs (the saurischian clan) had long shown evidences of feathers and protofeathers. The structures of barbs and barbules were quite clear in binoc plane microscopes. The Saurischians are the line that was the common ancestor for both birds and "lizard hipped" dinosaurs .

Bakker had been the one who first detected the similarities between specific species of dinosaurs (especially the early Triassic and late Permian proto mammal dinos) and warm blooded descendant species. The interior of the bones, the upright stance, the large nares , and overall cavity capacities suggested that warm bloodedness had developed quite early in evolutionary history. Were all dinos warm blooded? cant say but, remember that all these "modern" dino reconstructions are done with a "life style"model in mind and then the features are added on with respect to that model. In otherwords they could be all wrong but its become very fashionable to show T Rex as a savage upright, highly m obile (assumed warm blooded) guy with lots of horizonatality going on. COlbert would roll over in his grave.

thank's for that, perhaps the bone features relate to that of a bird but it's fair to add that there must also be a connection to the reptile family , de evolved is there any weight in that, dino's from what we no were made up of a variety of element's and form's that have blatent visable connections to the animal life here now , megliadon , great white , lizard's that run on there hind leg's when attacking prey the turtle , the crocodile dino's were egg layer's I refer to a theory that we can't just ignore what has been found from the past and not look at animals we have today and just believe that there is maybe a bigger connection to the jurasic period for that matter look at our bird life and lizard species for simularities .