What caused the dinosaurs to die?

Tue Dec 13, 2005 11:19 am by Tawakalna

but it did, colleague. lots of other species were wiped out both on land and sea, not just dinos (and dinos were a massive category of animals anyway, from huge land monsters to little chickenosauruses and great big whale-like things) We know this because lots of species with fossil remains under and up to the KT boundary aren't evident above the layer, ergo we can presume from that absence that they didnt survive.

HOWEVER... this doesn't mean that it was exclusively the asteroid that did for the dinos, as its q possible they were on their way out anyway or that the Earth's ecosystem was already in a precarious state for which the asteroid impact was the final catalyst of change, or even that the rise of smaller predatory and scavenging mammals (rabbits) reduced dino nests to critical levels or that pollution or disease weakened the shells and reduced the population.

What we can state is that AS YET no dinosaur remains (or any other species we presume got extincted) have been found after the KT layer, only before. They may be found, and if so then we have proof the dino's weren't killed off, but survived in some form only to be finally extinctified later. Myself I find it hard to beleive that animals that could successfully fill almost every ecological niche for hundreds of millions of years were all killed by a single catastrophe. And why didnt frogs die out when they are even more sensitive to change?

there are a LOT of unanswered questions, and while there's no credible doubt that an asteroid impact off Yucutan 65 million years ago did drastically reduce life on Earth, we don't really know (yet) what the consequences of it were and we don't really know (yet) how catastrophic it was.

so it is just about possible that some descendant of dinos* may have lived on long enough to be contemporaneous with proto-humans, but not very likely. However, postulating human existence back 65 million years is even less likely (as in not possible at all)

(* note - isolated animal populations can live on after their main species/genus has died off, for example the pygmy mammoths on Wrangel Island which survived until really only a short time ago, but long long after their larger cousins had become extinct on the Eurasian and N American mainlands. And there are constant rumours of the Loch Ness monster and other beasties around the world like the Naga in Burma/Thailand which may well be survivors from ancient times - look at coelocanths)

but unless someone's discovered the Valley of the Dinosaurs or the Lost World, sorry FD i can't buy into human footprints alongside dinosaurs. I keep an open mind on a lot of weird and alternative stuff but that one stinks of a fake. I'm rather more worried about genetic experiments to bring extinct species back to life a la Jurassic Park, which I believe some Japanese researchers are up to right at the moment! ok theyre wortking on wooly mammuffs and rhinoceroseroses and sabre-toofed cats n stuff, but I betcha those are just trial runs to receate velociraptors which will escape and breed and be smarter than us and wipe us all out.

as to older species of humans, the Insurance Man is rather more knowledgable about that subject, and I'm sure we'd all appreciate some of AELK's professional input, even The Dog.

Edited by - Tawakalna on 12/13/2005 11:53:02 AM

Tue Dec 13, 2005 11:53 am by Recusant

Finalday, how do you disprove the existence of something? Take extra-terrestrial life for example. To prove there is no life outside of earth you'd have to search the entire universe all at the same time and find no life at all other than what we have here. Whereas just one single encounter is all it would take to prove that aliens exist. So how do you expect anyone to prove we weren't there at the same time? All we can point to is a lack of evidence.
The largest mammalian remains known from before the Cretaceous period were of a creature the size of a badger, it's fairly improbable that physically weak human beings without technology would survive with predators like the dromaesaurids and various other therapods around (creatures like velociraptor of various sizes). How come no cave art anywhere shows dinosaurs? And if we were around at the time, what killed off the dinosaurs that we survived? I'd love to know what the proof is, that humans and dinosaurs co-existed, and whether it's been subject to any scientific scrutiny.

As for the asteroid not wiping out creatures other than the dinosaurs, it appears it destroyed almost all forms of megafauna other than the cold-blooded reptiles. The sea going reptiles like plesiosaurs, ichthyosaurs and mosasaurs were wiped out, the smaller pterosaurs had disappeared by the end of the Cretaceous presumably after being out-competed by the newly evolved birds and only the larger species of pterosaur were left, who also died in the extinction. Insects and small mammals can survive through scavenging and surprisingly high fertility rates. Reptiles are capable of going without food for prolonged periods of time, especially if the temperature dropped (as might be expected when dust from the asteroid impact heavily clouds the sky) as this will slow down their metabolism. Also in their favour is that it takes a slightly warmer egg for the embryo inside to develop into a male. There would be more females in future generations until temperatures warmed again, while only a few males would be needed to continue the species existence.

Tue Dec 13, 2005 12:46 pm by Tawakalna

one would have thought that warm-blooded reptiles would have survived the heavily-constrained post-catastrophe conditions rather better than the cold-blooded species? it's not as if they were much higher up the food-chain than some of the cold-blooded species. Crocophiles are cold-blooded and very sensitive to climatic change (I'm informed so) yet they survived, why not a little scavinging warm-blooded chickenosaurus. And why did crocophiles and turtles survive and not plesiosaurs or icthyosaurs or the like? (well, they might have done but they probably didn't)

it's not that I don't believe the catstrophe theory, i do of course. but i'd say that it's not quite all the answer, and there are quite a few anomalies with it. Myself i go with the tipping-the-scales thory, that the ctastrophe pushed an already fragile ecosystem over the brink (for a time) and so constrained the dinosaurs that they rapidly died out, but if theyd already been getting progressively fewer, evolutionary changes had commenced that ensured not only their vulnerability and by extension species that were dependent on them, but also left mammals and other species in an advantageous position against an attentuated dinosaur population which shaortly fortuitously was effectively finished off by the asteroid. Perhaps a slower gradual increase in mammals and a less radical but equally inexorable change in environment might have also finished the dinosaurs off?

edit - rec i read your post again and you'd already answered my question! sorry chum I'll pay more attention in future!

furher edit - i use way too many adverbs!

Edited by - Tawakalna on 12/13/2005 2:08:53 PM

Tue Dec 13, 2005 1:23 pm by The Evil Thing

There is physical proof that humans were here with the diasours.

Oh dear, oh dear, oh dear... No there isn't.

Source 1

Cretaceous (146 to 65 mya):-
Major extinction includes dinosaurs and ammonites (K-T)
Appearances include: flowering plants (angiosperms); lizards; placental animals (early mammals) ; snakes; social insects; marsupial and primitive placental animals
Modern insect forms radiate

Pliocene (5 to 1.8 mya):-
Ape-like ancestors of modern humans (Hominids), the australopithecines

Pleistocene (1.8 mya to 11,000 yrs):-
Neandertals appear and disappear; Homo erectus and Homo sapiens appear

According to this source, dinosaurs predate humans by approximately 63.2 million years.

Source 2

Dinosaurs are animals that dominated the terrestrial ecosystem for over 160 million years. Non-avian dinosaurs became extinct at the end of the Cretaceous period, 65 million years ago.

This supports the assertion in Source 1

Source 3

In 2002, a 6–7 million year old fossil skull nicknamed "Toumaï" by its discoverers, and formally classified as Sahelanthropus tchadensis, was discovered in Chad and is possibly the earliest hominid fossil ever found.

This also supports the assertion made in relation to Source 1. However, it also pushes the date at which homids are first believed to have appeared by 1 to 2 million years.

Source 4

Modern forms of Homo sapiens first appear about 195,000 years ago.

Specimen can be found here.

That's all the sources I can be bothered to cross-check and browse through at the moment. If you want more then just ask. I admit that I have provided evidence opposing your opinions but it's hard to find something that isn't there, and 'proof' by contradiction is still 'proof'.

Further from what Rec said:

Finalday, how do you disprove the existence of something? Take extra-terrestrial life for example. To prove there is no life outside of earth you'd have to search the entire universe all at the same time and find no life at all other than what we have here. Whereas just one single encounter is all it would take to prove that aliens exist. So how do you expect anyone to prove we weren't there at the same time? All we can point to is a lack of evidence.

It is actually the same idea with the boiling point of water at sea level air pressure. To test the theory and prove it one would have to boil water at that temperature at every point in time in every single point in the universe, with conditions being made to match even where they don't exist. Possible? No. Point made?

Oh, erm, it seems I got somewhat carried away here... I would just like to point out that at no time did Finalday attempt to link his beliefs to religion or faith and they are therefore fair game for me to 'attack' as inaccurate.
Getting back on topic, ahem:

Once again, good old Wikipedia sums up the information on the asteriod collision theory for extinction of the dinosaurs. (Link)

I'm not evil, I'm morally challenged

Tue Dec 13, 2005 3:07 pm by Accushot

There is physical proof that humans were here with the diasours.

Er...that's a good one. Given that mammals hadn't progressed past mouse-sized creatures at this point it seems highly unlikely that humans were around at this time. In fact I would say it is impossible given that the descendancy of humans from early mammals has been proven to be accurate. No way in hell, sorry.

The problem with those that say there weren't, is they have no proof that there wern't people here. As in, according to some scientist, people were not here, therfore they truly have no proof how the dinasaurs died, only guessing. If I find a deer dead, I can have it studied, and see if a hunter brought it down, then have proof.

Saying it hasn't been proven is, as Rec and TET have said previously, not really valid reasoning. If that's the case then we can't prove anything in the world. You have two eyes? Sure about that? Can you be sure that, at every point in the entire universe, you yourself would have two eyes? There's no way for us to absolutely prove anything.

The asteroid doesn't hold water, as one big enough to wipe out dinos, would also effect the other land animals as well.

Again, have you really checked all the facts? The asteroid that 'supposedly' killed off the dinosaurs struck the Earth with a force of 100 million megatonnes. As the scientist James Powell described it, if you exploded one Hiroshima-sized bomb for every person on earth you'd still be a billion or so short. Recent simulations have suggested that, if an asteroid just half the size of the one that wiped out the dinosaurs hit the planet now, 95% of the human population would be dead within the first day. That's over six billion people.

Another less well-known fact is that, since the atmospheric oxygen levels were around 10% higher than at present, the world was far more combustible. Above all, did you know that the floor of the sea where the asteroid hit was made of rock rich in sulphur. Apparently the impact turned "an area of sea floor the size of Belgium into airborne sulphuric acid, causing rains acidic enough to burn through skin."

The huge clouds of ash and debris thrown into the air would also have caused any surviving vegetation to die out. Additionally don't forget about the millions of rotting carcasses and the diseases that could arise from them; the world would not have been a pleasant place to live for many years after the impact.

And why weren't mammals killed off by the same disaster that did for the dinosaurs? It's been said that mammals may also have come extremely close to extinction, even with their advantages of being nocturnal, small and having a remaining food source. Perhaps we owe our existnce to a handful of injured survivors who managed to keep going and gain a foothold again.

Sorry for the long post, it's an interesting topic.

Edited by - Accushot on 12/13/2005 3:10:03 PM

Tue Dec 13, 2005 3:38 pm by Tawakalna

the earler Pre-Cambrian extinction was, apparently, even larger.

Tue Dec 13, 2005 4:38 pm by gromit

fight! fight! fight! fight!

sorry that really wasn't helpful was it?!

Tue Dec 13, 2005 4:44 pm by H.Q. Victor

Firstly, a lot of my sources would not be excepted, due to the nature of them. But on a science point, the dating methods have been proved unreliable. So you can not date things accurately. Carbon 14 dating was used on a living mollusk, and shown to be "Dead" for 3 000 years*. Lava rocks in Hawaii were tested by Potassium Argon that said they were 3 billion years old, yet the eruption was in 1801** The rocks taken from the moon were tested by radiometric Techniques, it varied from 700 million years to 28 billion.*** If Man was after the dinos by the stated 60 million years, I want to see the proof. No one was a round to witness their demise and a period of 60 million years would wipe out the evidence.

*- Science, Vol. 141 (1963) Pg 634 M. Keith and G. Anderson

**-Funkhouser & Naughton, Journal of Geophysical Research, Vol. 73, July 15, 1968, Page 4601

***- John G. Read, "What is the scientific certainty of Evolution? " Scientific Representations. P.O. Box 2384, Culver City, California, 90230

The Great Dinasaur Mistake by Kelly Segraves Pgs. 34 - 39

Creation Research made up of scientists with information on erosion and its effect on the time table of the earth.

A fact - The total amount of sediment flowing into the ocean is 27.5 billion tons every year. There are 30.4 million cubic miles of continental crust above sealevel having a mass os 383 million billion tons. 383 million billion tons devided by 27.5 billion tons per year = 14 million years.

Edited by - Finalday on 12/13/2005 4:45:55 PM

Tue Dec 13, 2005 5:23 pm by Recusant

Not all sediment just flows from land to sea! Sea creatures die and fall as detritus to the ocean floor. Further debris falls on it, it gets squished over an incredibly long period of time till the sediment becomes sedimentary rock and the impression of the creature what's left of it's body is turned to stone. Sea levels change and plate tectonics move the land and these creatures are found above ground. Similar things happen in swamps and lakes and rivers too. A lot of dinosaur remains are either found on coastal cliffs and desert areas. In desert areas, the sediment is left largely unaffected due to a lack of precipitation, meanwhile on coastal cliffs, as they are eroded back by the sea, it's possible to see prehistoric remains on the cliff just as they become exposed. As a kid, I remember going to a beach at a place called Reculver near Margate. Looking at the cliff you could see all the bits of old brachiopod shell absolutely everywhere, from the bottom and most of the way up what must have been at least a 40 or 50 foot cliff.
Finally, I don't want to be mean but where did that data about sedimentary flow and land mass above sea level come from? And more importantly how on earth was that obtained!? I can't even begin to imagine the logistics involved in finding that out.

Tue Dec 13, 2005 5:28 pm by H.Q. Victor

The erosion issue, is to disprove the time/dating of dinasaurs. That man was around when they were. Even if you took it from strickly a science point of view, why could man not be around with them? Many animals ar extenct, but did not die off millions of years ago. Many are on the verge of extention now, and that due to man's encrouchment in thier habitats.

Tue Dec 13, 2005 5:50 pm by Recusant

There is no palaeontological or archaeological evidence to even remotely suggest that we co-existed with them. If it was possible for humans to exist, it would therefore be equally possible that a whole plethora of other similarly large mammals could have existed alongside dinosaurs. Yet the only mammalian fossils we find in the same strata as those of the dinosaur fossils are small. The largest known cretaceous mammal was Repenomamus, described as being very roughly badger-sized and even so is considered to be the exception rather than the rule. It suggests that most of the ecological niches for larger creatures were already occupied by the dinosaurs with an evolutionary headstart of several million years, meaning mammals would not be able to diversify till after their extinction.

EDIT: wow, my 1000th post here on TLR, only took almost 3 years to get this far! Just glad my 1000th post wasn't a load of spam

Edited by - Recusant on 12/13/2005 6:47:57 PM

Tue Dec 13, 2005 10:25 pm by The Evil Thing

Finalday, please provide Scientific sources rather than theological ones.

I think we can safely discard "The Great Dinosaur Mistake". I quote:

And again, how does the dinosaur fit into the Biblical framework?

Answer: It doesn't 'fit in' to the Biblical framework. If you want to claim to be using science, use it properly . Science would ask, "How does the Biblical framework fit with dinosaurs, and if it doesn't, how can a change it so it would?"

Creation Research:
Hmm, enough said, methinks

Journal of Geophysical Research:

Lava rocks in Hawaii were tested by Potassium Argon that said they were 3 billion years old, yet the eruption was in 1801

Please give us a link to the entire article.
Quite possible, there are anomalies in everything, assuming that it is an anomaly and the rocks weren't 3 billion years old.

What is the scientific certainty of Evolution?:
I could answer this by saying "very". But somehow that wouldn't satisfy you, I venture to guess. Again, this falls under the same banner as Creationism. Ooops.

If Man was after the dinos by the stated 60 million years, I want to see the proof. No one was a round to witness their demise and a period of 60 million years would wipe out the evidence.

And no-one was around to witness some mythological being defy ALL the laws of physics, relativity and general common sense to create an entire universe piece by piece.

A fact - The total amount of sediment flowing into the ocean is 27.5 billion tons every year. There are 30.4 million cubic miles of continental crust above sealevel having a mass os 383 million billion tons. 383 million billion tons devided by 27.5 billion tons per year = 14 million years.

Not quite getting the point behind this, are you? Sediment cannot be replenished? Geophysical changes cannot alter the rates of sendiment flow ? NOT a fact, essentially.

I want to see the proof.

Will dozens of peer-reviewed documents and tests do? Or would you prefer something more concrete, like... Genesis, perhaps?

I don't want to turn this into a religious debate but I can only work with/against what I'm given. If you don't want Christianity in the firing line, don't cite it as a source.

(BTW, I'm tired so this may seem... abrupt and abrasive)

Wed Dec 14, 2005 1:57 am by Accushot

All good points. One more from me:

The erosion issue, is to disprove the time/dating of dinasaurs. That man was around when they were.

Not sure you understand where we're coming from here: it is 99.9% impossible that humans were around at the time of the dinosaurs. That 0.01% is just to avoid making me sound too stubborn, personally I'd say 100%.

Man is a mammal - Fact.
Man evolved from lesser mammals - Fact.
Man evolved from lesser mammals that were around at the time of the dinosaurs - Fact.

Unless, that is, you want to start arguing over the lack of proof for evolution. Based on the evolutionary state of animals at that time it would be next to impossible for humans to exist, if not completely impossible. Unless you're suggesting that humans evolved from mice-like creatures in the space of about a million years. The human brain alone took many many millions of years to develop into a state where humans even acquried "self-awareness".

But even if humans were around at that time (They were not !) there is no way they could have competed with the dinosaurs. Aside from the obvious problem of being hunted and killed humans would have had to cope with a vastly different environment. Any 'humans' around at that time would have looked so different to us today that we wouldn't class them as humans.

And that's another point. Any humans alive at that time would not be humans, in that they would not be a member of Eukarya -> Animalia -> Chordata -> Vertebrata -> Mammalia -> Primates -> Hominadae -> Homo -> Sapiens. According to your theory they wouldn't even be a member of mammalia, the mammals, and so would be no more closely related to us than any other vertebrate. They could be less closely related to modern humans than fishes, sharks, frogs or indeed any of the now extinct prehistoric vertebrates. (Edit: In fact, no more closely related than the dinosaurs!)

The problem with your argument is that you haven't provided any proof at all, merely conjecture. And then you claim that generally accepted facts are incorrect because there isn't enough proof to back then up.

Edited by - Accushot on 12/14/2005 2:04:35 AM

Wed Dec 14, 2005 6:48 am by Indy11

Ooooooh! This is really really cool. A discussion about, er, that theory thing in science that is causing lots of issue over here in the US.

There are differet layers to this issue. First, is it "Science" or "science?"

I think what is needed is an agreement on what the scientific method is. This is widely ignored by folks who want to wade into this discussion. The most important aspect of that being to discuss what constitutes proof.

Then there is the need to discuss the difference between what constitutes prevailing scientific opinion and what doesn't and why.

Any takers?

PS: It is the Paluxy River find in Texas. It was first interpreted to be an association of human footprints adjacent to dinosaur ones by Henry M. Morris, PhD, a hydrogeologist. Because of his lack of training in paleontology, as such, his interpretation of the footprints largely has been considered to be flawed.

Edited by - Indy11 on 12/14/2005 6:52:05 AM

Wed Dec 14, 2005 6:54 am by zazie

This (interesting) discussion shows some of the main problems of all discussions between people 'who believe in' and people who don't.

"Creationalists" (is that the word ?) and "Intelligent Design"-ers pretend to be/think scientifically in the sense of 'we have scientific evidence' that something is right or wrong.
But this kind of argument is only a mean to prove that science is wrong (or - at least - the results of science are not reliable).

Difficult to stop such arguments because scientists always admit (it's part of the scientific method) that they have only a provisional answer.

On the other side there is absolute truth and conviction.

FD presented a very typical example with the erosion-thing. It sounds VERY scientific - sorry for the sarcasm. But it is hard to verify or falsify.

Last, and different point: please be aware that the the so-called extinction of the dinosaurs took several million years . No Big-Bang. No instant killing.

If it was caused, accelerated or increased by a asteroid is still in discussion (despite the big Yukatan-asteroid and the traces of Iridium).

What does this mean? We will probably never have 100%. But hey - 90 % is fair.

Can't resist to give you another example of the same problems with a discussion on scientific facts and how to interprete them.

Facts:
A) Global Temperatures are growing, glaciers and the ice in the arctic/antarctica is melting

Global Temperatures have been higher before, only 2000 years ago the alpine glaciers had almost completely vanished.
C) CO2-level in the atmosphere has never been as high as it is today during the last 600'000 years

Question:
Is there a connection between A and C ?

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