[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Due to press of work, I am unsubscribing for now. As a parting
shot, I will try and amplify Stan's answers to my questions (I
kinda knew some of them, even in my lay manner, but the key was
(I thought) to collect the questions newbies would ask most as
well as some of the gadfly (eg creationist) type questions).
I have a few suggestions about how to polish it up for the
uninitiated (and, like me, semi-initiated).
Excerpts from mail: 3-Aug-94 Re: FAQ's Stan Friesen@ElSegundoCA (4948)
|> From: Larry Loen <email@example.com>
|> Proposed answers:
|> > How about also:
|> > 1) Are all ancient reptiles dinosaurs?
I was hoping for an amplification here about Pteranodons and
Elasmosaurs et. al.
|> > 2) I heard there were mammals around when the dinosaurs were alive.
|> > What were they like?
|> There was considerable variety. Many were similar in body
|> form to shrews. There were also forms similar to, but distinct
|> from, modern rodents. In addition, opposums had already evolved
|> by the end of the Mesozoic. This is just a small sample.
Good answer. Might be of interest to then follow with a brief
discussion of "protoreptiles" and "protomammals" (as Bakker calls
them in Dino Heresies) as well.
|> > Do we know why they replaced the dinosaurs?
|> Not with any certainty, but the most likely explanation is simply
|> opportunity. That is, they were still there, the dinosaurs
|> weren't, so they took advantage of the new opportunities.
|> This is a special case of the genral rule that when a group finds
|> itself in a situation with lots of unused resources, it diversifies
|> rapidly to ustilize those resources.
|> > 3) I heard someone say that birds were dinosaurs. Is that true?
|> This is a matter of taxonomic policy, not of facts. The vast
|> majority of specialist agree that birds are *descended* from
|> dinosaurs. For some, the cladists, this in itself is sufficient
|> to require that birds be classified as dinosaurs. For others,
|> this is not sufficient, and they usually keep birds in a seperate
|> Either way, the actual *facts* of the matter are the same, the
|> only difference is how those facts get represented in a classification.
|> In thinking about this it is important to realize that classifications,
|> even "natural" ones, are in large part human artifacts, not facts
|> of nature. (Though the underlying relationships we try to capture
|> in the classifications *are* facts of nature).
Good answer, but I think slightly too technical for newbies. A newbie
would not know what "taxonomic policy" or a "cladist" is even if I sort
|> > 4) What killed the dinosaurs?
|> This is not know with any certainty.
|> One widely held hypothesis is that the impact of a gigantic meteor,
|> probably in the Yucatan area, near the town of Chicxlub, caused
|> widespread disturbances that drove many groups, including the
|> dinosaurs (except the birds) to extinction.
|> Many paleontologists doubt this was, by itself, the sole cause.
|> Some have provided evidence of more gradual extinctions than the
|> impact hypothesis would allow, although others question the
|> significance of these results.
|> Other suggested causes, or contributing factors are the extreme
|> lowering of sea levels at the end of the Cretaceous, the massive
|> volcanic outpourings going on in India at the time (forming the
|> enormous lava plateaus called the Deccan Traps), and even disease.
You might consider adding that it is "who survived" as well as
"who died" that makes this such a difficult puzzle. A lot of
answers work until one tries to explain who made it through the
K-T barrier, not just who died, or so I read it.
|> > 5) Dinosaurs lived in swamps, right?
|> Some did, most did not. The main swamp dwelling dinosaurs I know
|> of are Edmontosaurus, and perhaps Saurolophus. (Both of which
|> are "duck-billed" dinosaurs). Most other dinosaurs, including
|> the msot of the other "duck-billed" dinosaurs and the gigantic
|> sauropod dinosaurs were NOT swamp dwellers.
For newbies, I would expand "gigantic sauropod dinosaurs" to name
a few famous representatives like Apatosaurs or Brachiosaurus and
explain exactly why scientists now ditched the swap bit (more understanding
of the ancient climate where the fossils were found, water pressure/
buried in mud arguments or whatever).
|> Indeed, some, like Euoplocephalus and Pachycephalosaurus, probably
|> spent most of their time in the uplands, well away from major bodies
|> of water.
|> > 6) Dinosaurs and people lived together, right? (And, aren't there
|> > tracks in Texas that
|> > prove it?)
|> No. The tracks in Texas are all dinosaur tracks, which do
|> not not really look like human foot prints if one looks closely.
|> [That is, except for a small handful of artificially modified tracks].
I wouldn't mince words, here. The few human-like ones are known (or
so I thought) to be fradulently altered. Shouldn't we say so outright?
|> The longest axis of these tracks is straight down the center,
|> rather than to the inside as in human tracks, and there is no
|> trace whatsoever of the 'arch' of the foot so prominant in real
|> human footprints (not to mention the large size of the tracks).
|> > 7) Scientists are always saying things like "Triceratops lived in the
|> > late Cretaceous period, about 65 million years ago". How do they know
|> > how old things like dinosaur fossils are?
|> By correlating lots of evidence from various sources.
|> First, it is possible to determine the *relative* ages of various
|> forms by noting the sequence in which they occur in the fossil record.
|> Paleontologists have done this in considerable detail, producing
|> complex, detailed correlations of various rock strata around the
|> world. Using this scheme of correlations, Triceratops lived during
|> the time period called the Late Maastrichtian Epoch.
|> To get dates, paleontologists and geologists use radiometric dating
|> techniques (there are quite a number of them, each with its own
|> particular range of usefulness). All of these techniques are
|> only usable under certain conditions, so only some rock beds can
|> be dated this way. However, since the ones that are dated are
|> usually also part of the grand correlation scheme mentioned above,
|> it is possible to interpolate dates for almost all major fossil beds.
|> In the case of Triceratops, there are several dozen localities
|> of Late Maastrichtian age that have been dated. These dates
|> generally range from 65 to 67 or so million years ago. So we
|> conclude that Triceratops lived from 67 to 65 million years ago.
|> firstname.lastname@example.org email@example.com
|> The peace of God be with you.
Thanks for the really good answers. Now, someone collect this
stuff up and prepare it for regular posting!
- Re: FAQ's
- From: Tracy Monaghan <firstname.lastname@example.org>
- Re: FAQ's
- From: Stan Friesen <swf@ElSegundoCA.NCR.COM>