Dinosaurs and Evolution

Factual Questions
21

As usual, I’m late to the party, so all the good answers have been taken. So, I’ll just throw this out there:

“Dinosaur” is a pretty expansive group, comprising over 1,000 genera, not including their feathered descendants. They existed, as a group, for a period of about 160 million years. During that time, species arose, thrived, and died out. At any given time, there were, perhaps, representatives from about 100 genera walking around.

Humans, on the other hand, are but a single species (perhaps two or three, depending on who you ask in human paleontological circles). They have existed for, perhaps, 5-10 million years – little different than any other vertebrate species, including individual dinosaur species.

As such, it is rather unfair to compare “humans” to “dinosaurs”; indeed, it’s probably not possible to do so in any meaningful way.

Now then: intelligence, like many other things in nature, is something of a continuum, between “pure instinct” and “ability to build jet aircraft”. Within any group, be it mammal, dinosaur, or fish, there are likely to be representatives from all over that continuum. Predators, in general, are “smarter” than their prey, regardless of what group each belong to (for the simple reason that it takes more problem-solving ability to catch prey than to eat leaves or grass). So, it’s also a bit unfair to refer to dinosaurs as a whole as “stupid”; certainly, some of the large herbivores were not likely to be anything close to a Nobel candidate, but some of the smaller predators (in particular, Troodon, near the end of the Cretaceous) had larger brain/body mass ratios than one might expect for them being glorified reptiles. So,there were,indeed, dinosaurs which were getting “brainier”, at least.

However, one should never make the mistake of assuming that one can determine something as vague and conceptual as “intelligence” from the fossil record. We don’t know, nor do we have any way of knowing, how smart any given dinosaur was. Some appear to have exhibited complex social behavior, such as the ability to hunt in packs (e.g., Deinonychus). Others appear to have had complex nesting behavior and parenting behavior – traits not generally attributed to "typical " reptiles.

All we do know is that humans are relatively unique, simply by virtue of being in the right place at the right time. Our ancestors paved the way for our smarts; we simply took the next step. However, if the clock were turned back, even just to the end of the Cretaceous, there are no guarantees that things would turn out the same. It should be noted that after the K-T extinction, mammals did not immediately take over in a number of locales: birds (which, remember, where still, technically, dinosaurs) did. Think Dinornis. So, mammalian superiority isn’t all it’s cracked up to be.

22

Spoken like a true child of a dinosaur. :slight_smile:

23

One thing thats important to remember about intelligence.

The things most people attribute to human intelligence (“ability to build jet aircraft”) are really a result of what could be called cumulative human intelligence. If I asked you to go build me a jet aircraft using only what you can do phyically (using strength and intelligence), you would be hard pressed to succeed. If you expect a dinosaur to build a jet, it needs that cumulative intelligence and experience.

As a linguist, my opinion is that evolution for us (humans) came in the form of advanced communication. Maybe nothing more. OK, so maybe we have higher cognitive abilities. Maybe our problem solving skills are more powerful than simply predator/prey. But I think if you give dinosaurs the ability to communicate with other dinosaurs extensively AND the ability to record their collective experiences…flash forward a few million years…Dino-pilots.

Does thay make sense?

24

Osiris: Here’s an interesting link to an article on pulmonary function in theropods: http://cas.bellarmine.edu/tietjen/Ecology/pulmonary_function_and_metabolic.htm

As to a four-chambered heart, one was suposedly found on the herbivore Thescelosaurus, but see here: http://www.sciencemag.org/cgi/content/full/291/5505/783a

  • Tamerlane
25

Although I am not a linguist, I have to agree with jayrot; I also believe (unfortunately, with little evidence) that communication was the key. Before I continue, the fossil record shows that dinosaurs were in serious decline even before the presumed catastrophe and I know no explanation for that. But the main point I wanted to make was not only didn’t dinos evolve human-type intelligence, but neither did a number of lines of great apes, including chimps and gorillas. And we have irrefutable evidence that their line was capable of it. But for whatever reason, their environmental pressures did not lead to greater (or at least human-type intelligence). Chimps are stronger than humans and gorillas much stronger. For all I know, they may in some ways be even more intelligent. At least they have never chosen George II as their leader. But in one respect, they are not even in the race and that is complex communication.

26

::wipes nose with back of hand::

See, now here’s your problem. You got your clauses all out of order. Let’s see if we can rework this thing so it makes some sense.

::hammering, grunting, power drill noises, jackhammering::

Here you go:

There’s still a couple of problems, like the idea of primitive traits vs. advanced traits, and we still have this leftover prepositional phrase that I don’t quite know what to do with, but as you see, you actually answered your own question.

That’ll be $200.

27

Tyrannosaurs in F-14s!!!

every thread needs them.

28

<b>everton</b> Nah dude, is sweet.
Yes my typing is shocking. English is my first language but i am badly dyslexic and if i don’t reread my posts half a dozen times it comes out like gobeldy-gook to me also.

I just get lazy some times.

As for dinosaurs turning into birds - i did not mean all of course i should have said the Birds evolved from dinosaurs.

As for intelegence, you evidence that they existed without much change doens;t really discount me as we had existed also and had not changed … then we did.

29

Even that’s not necessarily true. Some scientists believe that birds evolved directly from certain dinosaurs, others believe that birds evolved separately from a different, older, group of reptiles. Maybe that’s a question for another thread? Maybe it’s already been discussed before on these boards.

We didn’t exist back then, animals capable of evolving into us did. As bryanmcc explained earlier, it’s not possible for every line to evolve along every path. For instance, there will never be any decendents of insects that are as big as a lion because insects have a very simple respiratory system and an exoskeleton that both limit body size. Having “made that decision” the evolutionary process has frozen insects (and all their decendents) within certain limitations regarding body size.

Go alien and Osiris have both hinted at limitations in the dinosaurs’ physiology, such as cold-bloodedness, that may have prevented them from ever developing along the lines that mammals did to produce us. Of course it’s possible that some dinosaurs were more intelligent than we give them credit for, but its also reasonable to assume that if there was an ecological niche for large-brained animals during the Mesozoic era, and if dinosaurs had the capacity to evolve into that niche they would have done so. They didn’t. If the reason why they didn’t was physiological limitation, then it never would have happened asteroid or no asteroid.

30

I suppose the whole question might be rephrased as, “why was there a selective pressure for mammals to evolve big brains, and not for any other order of vertebrates?”.
You can eliminate ectothermic animals because big brains need to be kept warm to be any good. And you can eliminate most birds because flight places a strong premium on minimum weight, especially in the head. But that still leaves big ground birds, and presumably the dinosaurs, in addition to mammals.

Take the ostrich: It weighs a couple of hundred pounds, but I don’t think it’s brain is any bigger than a housecat’s. Now some birds such as crows and parrots have been shown to be remarkably smart, but that would simply switch the question to “why do mammals have such overgrown brains?”.

And for that matter, mammals weren’t always notably brainy. When reading about primitive mammals in the early Cenozoic, I keep seeing the comment that they were smaller brained then modern mammals. So I guess you could ask, “Why did mammals start getting much brainier in the last 25 million years?”.

31

It should be noted that very few scientists (Alan Feduccia chief among them) do not accept the “dinosaurs to birds” theory.

There is much evidence to indicate that dinosaurs were not “cold-blooded”. The smaller ones were very likely fully endothermic, and the larger ones, if not naturally endothermic, would likely have been what are termed “mass endotherms” - that is, simply by virtue of being large, their body tempertaure would have to have been maintained at higher-than-ambient temperatures. Besides which, I would caution against making absolute statements regarding the connection betwen physiology and intelligence. Octopuses (or however you pluralize that) and cuttlefish, for example, are considered to exhibit quite a deal of problem-solving ability, despite not even being vertebrates.

It is also fallacious to believe that “if they could have, they would have” when it comes to any evolutionary novelty. The directions evolution takes are dependent on a variety of factors, not the least of which are what traits are available for for variance, which variations actually occur, and which of those variations that occur are most detrimental or beneficial at that time. If it is the case that braininess simply doesn’t provide any added survivability to an organism, then there is no reason to think it will evolve, even if all the pieces are in the right place.

Also, please keep in mind that, as I mentioned, there were dinosaurs near the end which were evolving larger brains, and were already well above the standard reptilian curve. This does not necessarily mean that, had they not been wiped out at the end of the Cretaceous there would be dino civilizations now; it only means that one cannot conclude that all members of the dinosaur lineage were to stupidity simply because they weren’t mammals.

32

So, humans have been evolving for 165 million years and today is the result of that? Hmmm… Either you’re mistaken or our ancester’s were dumb as dirt.

33

If you consider your typical mouse dumb… then yes, you’re right.

34

Pedant Powers Activate!

Octopodes. (Note: No normal person uses this form.)

Pedant Powers Off

35

Jayrot:

<<. . . are really a result of what could be called cumulative human intelligence. If I asked you to go build me a jet aircraft . . .>>

Ian Stewart and Jack Cohen used the phrase “extelligence” to describe this. When I think about the difference between what I’ve figured out for myself and what I’ve learned from someone else it is very humbling. And most of the things I’ve figured out built on someone else’s ideas.

We’re not standing on the shoulders of giants, but on a huge human pyramid. (I’m having a flachback to the story of it being turtles all the way down, probably because Stewart and Cohen collaborated with Terry Pratchett to write The Science of Discworld and The Science of Discworld II.) ((Wonderful books by the way. Although I’ve talked to many people who were puzzled by the fact that each was a fantasy novel combined with a science book. You have to shift gears slightly from chapter to chapter.))

Savaka - that was a masterful reply. And thank you DrFidelius for gracing us with your Pedant Powers.

36

Well, most students of Miskatonic U. know it. It’s home team.

Go Pods!

37

I don’t know why I’m bothering to nitpick a hijack, but “Pods”, as in the mascot of Miskatonic U., is short for “cephalopods”, which refers to the category (class?) of mollusks which includes octapodes.

And DrFidelius, what makes you think that there are any normal persons here?

38

The Fighting Cephalopods, to be precise.

And “-podes” is bisyllabic. As in “Antipodes” which means “Where Blokes and Sheilas and Kiwis Live.”

39

Hey, why not ask why mammals are still so primitive? I mean, the biggest land mammals are what, only a couple of tons?
Surely size is a better indicator of evolutionary advancement than some bizarre, virtually-impossible-to-measure aspect of behavior (which we all know is very environmentally- and situationally -dependent). I mean the evolutionary ladder is clear, from bacteria, to larger, true cells, to multicelluar organisms, to insects and other lower orders up through fish, reptiles, birds and mammals, to the larger, therefore clearly more advanced, dinosaurs.

No obviously, that’s ridiculous. The only rational way to rank species along the evolutionary ladder from least to most advanced is by sexual dimorphism – how different are males and females. Think about it: bacteria don’t even have well defined males and females, worms are often hermaphrodites, but in more advanced species males and females become progressively more defined. Using this, clearly superiour, way of ranking, dinosaurs are sadly it appears only moderately advanced (though it’s hard to tell from fossils), along with humans, while insects range from very primitive to very advanced. Certain deep-sea fishes are of course the pinnacle of evolution on this planet.

Of course, I’m not really arguing this, just trying to make the point that there is no such thing as an ever ascending evolutionary ladder, and using any trait to try and create the ladder is ridiculous, even such an interesting trait as ‘intelligence’.

40

If this guy had evovled enough to avoid lung cancer, he would show up and straighten this out:

“Humans are not the end result of predictable evolutionary progress, but rather a fortuitous cosmic afterthought, a tiny little twig on the enormously arborescent bush of life, which if replanted from seed, would almost surely not grow this twig again.”

  • Stephen Jay Gould