Dinosaurs & Science

[Prince Cobra]

1) I doubt I have shared this in the Org. but apart from the Middle Ages, I am very keen on the Mezoic Period i.e. the dinosaurs. I really enjoyed the three films of Jurassic Park (esp. the 2nd one) and this was a good demonstration why some dreams should never come to reality. Yet, do you think it is technically possible to make the big mistake to revive the dinosaurs?

2) This thread can be used to discuss anything you wish about dinosaurs.

[Csargo]

What do you believe led to their extinction? I know the asteroid causing it, but I assume their are other theories out there as well.

[Prince Cobra]

What do you believe led to their extinction? I know the asteroid causing it, but I assume their are other theories out there as well.

Well, I think the dinosaurs were quite resilient so a single factor could not bring to their extinction. I think the vulcanic activity, the poisonous sulphur fumes and the asteroid: they all brought about their exticntion. In fact, even that was not enough in relative terms since for a shord period after that the birds, a close relatives of the dinos, managed to dominate the world for a limited period of time. The mammals were faster to adapt to the new conditions. Why the mammals were thriving was the big question. I have always wondered if being a dominating species weakens your surviving ability or it has something to do with the egg shell...

[Samurai Waki]

There's a few theories floating about that the Dinosaurs were actually extinct before the Asteroid, since they can't seem to find in Mineral Tables any record that the Dinosaurs died out en-mass. I don't really know whether that's true or not, but I thought it was interesting to hear that.

[Cute Wolf]

Just use some large lizard's egg cell, and insert dino's DNA..... now we can clone them.... but I think the scientists wass too scared....

[Ibn-Khaldun]

I don't think it's possible to bring them back. There just isn't enough DNA(if at all) for that.

[Ibrahim]

1) I doubt I have shared this in the Org. but apart from the Middle Ages, I am very keen on the Mezoic Period i.e. the dinosaurs. I really enjoyed the three films of Jurassic Park (esp. the 2nd one) and this was a good demonstration why some dreams should never come to reality. Yet, do you think it is technically possible to make the big mistake to revive the dinosaurs?

2) This thread can be used to discuss anything you wish about dinosaurs.

1-it is, but not the way Michael Chrichton envisioned it; the best way is via genetic engineering of avian dinosaurs (i.e birds) , and even then you can only recreate, with the limited technology we have, dinosaurs long or near the avian branch.

2-thanks.

Rhyfelwyr is, of course, correct.

On a more serious note though... I find it fascinating that the dinosaurs got so totaly wiped out. Specially since avian dinosaurs and mammals obviosly survived (along with other species).

much better.

there are almost 10,000 species of them alive today. of course they are now known as "birds", but they are in fact highly derived theropodan dinosaurs. If anyone wants to know how that is the case, look for theprof1988 ( a good friend of mine on YT), or Albukhshi (me! ); we both talk alot about bird/dinosaur relationships. or you can always grab a good book on the subject (my recommendation is "glorified dinosaurs" by Luis Chiappe.


N.B: when I mention dinosaurs from now on in a capacity seperate from birds, assume non-avian dinosaurs.

What do you believe led to their extinction? I know the asteroid causing it, but I assume their are other theories out there as well.

well, the asteroid alomst certainly didn't do it-at least not completely; if it had, the Amphibians would have had it; they are very susceptable to extreme climate change, as brought about by the meteorite; and the acid rain that would ineviteably result from the impact in the long run, coupled with the sun being blotted out, would have killed them dead. there is little to no evidence of Amphibians undergoing mass extinctions in that timeperiod, so the killer(s) was gradual. and that also measn that the meteor was not as deadly as originally thought. at best, it was a coup de grace. at worst, the dinosaurs were already extinct by then.

you have to look at the fossils (dinosaur and non dinosaur alike) from the maastrichtian (the last subperiod of the Cretaceous), and see the species diversity, specimens per species, and of course, the climate and geography of the planet 65.5 MYA, then compare to the Campanian, the subperiod preceding it. only then can we know for sure; but from the initial research, it seems that the extinctions of the latest cretaceous took millions of years to accomplish.

I recommend you read Dinosaur heresies by Dr.Robert T. Bakker-his book is in simple english, and it give the "disease" theory of the extinction; its not simply disease doing it, but a series of factors tied in with the paleogeography of the late cretaceous.

Well, big creatures need a lot of oxygen to survive. When the meteor hit, the air had less of it, and they got slower and easier to catch.

Did birds exist? I'm not certain. The bottom line is, larger creatures are generally more adapted to a particular enviroment, and are more vulnerable to changes. Presumably, smaller dinosaurs simply evolved into other reptiles, or mammals and birds. Global temperatures also probably dropped due to the debris in the atmosphere, which isn't exactly good for cold-blooded animals. Us humans can go most places, and are hard to exterminate.

yes and no; yes, Oxygen levels in the mesazoic were higher than today, but they didn't go down to levels lower than that in the mesozoic till after the dinosaurs kicked it; nor is the current O2 level lethal to large animals; Blue whales breathe air, and they weigh 200 Tons.

in fact, the meteorite wouldn't have had any permanent effect on the atmosphere, and only a smallish mount would be reacted, producing NO2 and NO3 (and perhaps SO2); all these produce the acid rain I mentioned above. the first chemical iirc also would have turned the sky reddish brown


and the part about smaller dinosaurs evolving in to mammals and "reptiles" was simply the most laugheable explanation I have ever seen-no offense, but it is simply ridiculous. I have never heard of this from any creadible evolutionary/paleobiological scientist, or any students of such, including myself (remember? I mentioned I'm stdying to be a paleontologist).

@ everybody: this is why people need to be taught evolution properly in schools:

Presumably, smaller dinosaurs simply evolved into other reptiles, or mammals and birds

there is no way in hell a dinosaur van evolve in "reptiles"(by that I assume you mean squamates: lizards), nor can they evolve in mammals-both cases would in fact defy evolution, as mammals and squamates are on two seperate branches of the evolutionary tree. and besides, mammals have existed sice the late triassic, and reptiles since the permian (omniotic animals have existed since the Carboniferous; reptile IMHO=diapsids+euryapsids, the latter being just derived diapsids (e.g plesiosaurs). and while some coelurosaur theorpods did indeed evolve into birds, this had occured long before the mass extinction.


and no, dinosaurs were/are currently not cold blooded. Ignore anything from Spotila et al. or Ruben et al.

Did birds exsist? they were around for 150 million years, having diverged from the Maniraptorans in the late jurassic, so of course they existed. modern birds however are ~100 MYA (I could be off, but I know they are From the mid-cretaceous).

Well, one problem would be the issue of so many dinosaurs being over-specialized. Examples- the giant sauropods(Brachiosaurus, etc...), the over-sized carnivores(T-rex, etc...), the oversized sea life(giant sharks, icthyosaurus, etc...). Even the "not as specialized" creatures like the duck bills were still very large and required a lot of food to eat. All it takes is something(like an asteroid ) to kick out a few links in the food chain and the whole thing would teeter over like a giant game of real life Jinga. Ignoring, of course, the enormous environmental impact such an impact would cause. Look at creatures like the Saber toothed tiger, giant sloth, and dire wolves that all consumed too much food to be able to sustain quick alterations in food supply. Over-specialization can lead a species to the top of a food chain for a while, but it also makes it less adaptable to change and more likely to go extinct in a period of turmoil.

first off, Ichthyosaurs and Sharks are not dinosaurs; your comment makes it sound as if they are.

second, Ichthyosaurs died out around 30 million years before the KT event; and giant sharks are a feature of the Cenozoic, not the Cretaceous or the Mesozoic in general.

third: correct on specialization, but most dinosaurs in the late cretaceous were not that specialized (compared to spinosaurs, dicraeosaurs, and others, all of which were long gone by the maastrichtian), nor were they overly large by dinosaur standards. However, they were indeed starting to get bigger again, after having shrunk a bit in the Campanian. a good example is the replacement of 30ft, 2-3 ton Albertosaurus, Gorgosaurus, and Daspletosaurus with Tyrannosarus, a 40 foot, 6 ton animal. a more accurate description is that the dinosaurs, by growing larger (almost certainly in response to Climate change-IIRC is was becoming more seasonal and cooler towards the end, which favors large animals. the reason why would take another post ), were setting themselves up for extinction due to other factors, specialization aside. I'll discuss this in a moment.

In fact, specialization has doesn't necessarily have anything to do with the size-though size can be a specialization. spcialization has more to do with the specific niche the animal occupies. Sinze may contribute to the specialized status, but not on its own. the Cheetah for example is not a very large predator by serengeti standards, but it is the most specialized. It deals with ultra fast prey in quiet and flat environments. the elephant on the other hand, is the largest animal, but oddly not as specialized: they'll eat leaves, bark, and even grass on occasion-though trees are best for their dentition..large size in fact can destroy a lineage simply because reproduction and life cycle rates go down, and when it does, it leaves the population vulnerable to sudden events that can wipe out the young/a considerable proportion of the breeding population, whereby destroying remarkeably easily the ability of the population to carry on.

thus large size,


So overall, Stephen Asen is quite close to the mark, though not necessarily the right combo: its most likely the case that no one factor did the dinosaurs in, but a series of ignominious circumstances did them in.

[A Very Super Market]

The clown is there for a reason Ibrahim, but you are forgiven for not knowing the glory of Jack Chick

[Ibrahim]

The clown is there for a reason Ibrahim, but you are forgiven for not knowing the glory of Jack Chick

didn't notice. my bad.

but you should have put a clown on the second one too.

well, I suppose this is an example of Poe's law striking again

[Prince Cobra]

Well, after reading your first post in the thread, I can only say, "Ibrahim, make another post, please." (Whenever you dig some leisure time, of course.)

[Ibrahim]

well, somebody finally did it; for the first time in history, the color of a dinosaur is known with a certain level of confidence; this is a redering of sinosauropteryx prima, as based on a paper recently published in Nature by Fucheng Zhang et.al, 2010, regarding the animal's coloration. apparently, some pigmentation was fossilized in the fur/feather coat, revealing a surprisingly colorful animal. thanks must be given to the person who drew this, since he did an excellent job depicting it.

Spoiler Alert, click show to read: 

any opinions?