KT boundry event
uraniumc...@yahoo.com
"T. Rex and the Crater of Doom" the title of which is a bit misleading,
and Mr and Mrs Rex do not appear.
I am puzzled, however, by his poor argument that after the KT boundry
event the mammals were able to take over the niches (large animals)
that dinos had previously occupied. The question arises: Why didn't we
get dinos all over again? Why didn't we get large reptiles, at least?
Why large MAMMALS?
NashtOn
Do you think anybody knows the answer to this? Obviousy, according to
the ToE, it's probably because determinism goes out the window and the
conditions that made for the "evolution" of dinos were not present after
they became extinct.
--
Nicolas
"The reason the theory of evolution is so controversial is that it is
the main scientific prop for scientific naturalism. Students first learn
that "evolution is a fact," and then they gradually learn more and more
about what that "fact" means. It means that all living things are the
product of mindless material forces such as chemical laws, natural
selection, and random variation. So God is totally out of the picture,
and humans (like everything else) are the accidental product of a
purposeless universe. Do you wonder why a lot of people suspect that
these claims go far beyond the available evidence?" Phillip E.Johnson,
The Church Of Darwin
Gary Bohn
news:1145305916.2...@t31g2000cwb.googlegroups.com:
Why *not* large mammals?
--
Gary Bohn
Science rationally modifies a theory to fit evidence, creationism
emotionally modifies evidence to fit a specific interpretation of the
bible.
uraniumc...@yahoo.com
Gary Bohn wrote:
> uraniumc...@yahoo.com wrote in
> news:1145305916.2...@t31g2000cwb.googlegroups.com:
>
> > I just finished Alvarez's book
> >
> > "T. Rex and the Crater of Doom" the title of which is a bit
> > misleading, and Mr and Mrs Rex do not appear.
> >
> > I am puzzled, however, by his poor argument that after the KT boundry
> > event the mammals were able to take over the niches (large animals)
> > that dinos had previously occupied. The question arises: Why didn't we
> > get dinos all over again? Why didn't we get large reptiles, at least?
> > Why large MAMMALS?
> >
> >
>
> Why *not* large mammals?
Not the question:
WHY large mammals and not large lizards, etc? Why not dinos all over
again? It had happpened before, many times!
uraniumc...@yahoo.com
Gary Bohn wrote:
> uraniumc...@yahoo.com wrote in
> news:1145305916.2...@t31g2000cwb.googlegroups.com:
>
> > I just finished Alvarez's book
> >
> > "T. Rex and the Crater of Doom" the title of which is a bit
> > misleading, and Mr and Mrs Rex do not appear.
> >
> > I am puzzled, however, by his poor argument that after the KT boundry
> > event the mammals were able to take over the niches (large animals)
> > that dinos had previously occupied. The question arises: Why didn't we
> > get dinos all over again? Why didn't we get large reptiles, at least?
> > Why large MAMMALS?
> >
> >
>
> Why *not* large mammals?
I just wrote to Alvarez. Perhaps he can refer me to someone else.
John Harshman
Several possibilities. The first is that perhaps it was random. With
pretty much all the large animals extinct, a variety of small animals
could have filled the large-animal ecospace. It just happened to be
mammals this time.
It could have been birds. No other dinosaurs appear to have survived. We
may theorize that endothermy is an advantage, ruling out other reptiles
or amphibians. So your question reduces to this: Why didn't birds
re-radiate to fill the dinosaur ecospace, rather than mammals? There may
be reasons, or there may not be. Why did dinosaurs become dominant
originally, when therapsids had been the dominant large land animals of
the Permian (and remained so in parts of the world through the
Triassic)? There may be reasons, or there may not be. Maybe it was a
coin toss both times; dinosaurs won the first toss, and therapsids won
the second one.
If it wasn't a coin toss, perhaps the answer is that mammals were closer
in ecospace already. Birds were mostly specialized for flight. Mammals
occupied all manner of niches for small and medium-sized terrestrial
animals, both carnivores and herbivores. All that was needed was to get
bigger. Being closer to the target zone, they occupied it first. After
that, incumbency wins out.
Some superiority of mammals to birds, of unknown nature, is suggested by
the fact that there *were* a number of large, terrestrial bird groups in
the early Cenozoic, some of them surviving until the Late Pleistocene.
They seem to have been most prevalent on the chunks of Gondwanaland
(Australia, South America, and for all we know, Antarctica) that we
always sneer at for having inferior mammals. But phorusrhacids at least
managed to invade North America during the great interchange.
We can speculate all we like, but the data to resolve these questions
are unlikely to be forthcoming.
Augray
<1145306762.4...@t31g2000cwb.googlegroups.com> :
>Gary Bohn wrote:
>> uraniumc...@yahoo.com wrote in
>> news:1145305916.2...@t31g2000cwb.googlegroups.com:
>>
>> > I just finished Alvarez's book
>> >
>> > "T. Rex and the Crater of Doom" the title of which is a bit
>> > misleading, and Mr and Mrs Rex do not appear.
>> >
>> > I am puzzled, however, by his poor argument that after the KT boundry
>> > event the mammals were able to take over the niches (large animals)
>> > that dinos had previously occupied. The question arises: Why didn't we
>> > get dinos all over again? Why didn't we get large reptiles, at least?
>> > Why large MAMMALS?
>> >
>> >
>>
>> Why *not* large mammals?
>
>Not the question:
>
>WHY large mammals and not large lizards, etc?
Mammals are warm-blooded, and dinosaurs probably were too, although
not in quite the same way.
>Why not dinos all over
>again?
Since birds are descended from dinosaurs, and the number of bird
species outnumbers those of mammals, one might argue that it *did*
happen again.
>It had happpened before, many times!
When?
John Harshman
> Gary Bohn wrote:
>
>>uraniumc...@yahoo.com wrote in
>>news:1145305916.2...@t31g2000cwb.googlegroups.com:
>>
>>
>>>I just finished Alvarez's book
>>>
>>>"T. Rex and the Crater of Doom" the title of which is a bit
>>>misleading, and Mr and Mrs Rex do not appear.
>>>
>>>I am puzzled, however, by his poor argument that after the KT boundry
>>>event the mammals were able to take over the niches (large animals)
>>>that dinos had previously occupied. The question arises: Why didn't we
>>>get dinos all over again? Why didn't we get large reptiles, at least?
>>>Why large MAMMALS?
>>>
>>>
>>
>>Why *not* large mammals?
>
>
> Not the question:
>
> WHY large mammals and not large lizards, etc? Why not dinos all over
> again? It had happpened before, many times!
What, exactly, had happened before many times? On the large animal
front, there was considerable jockeying for position. Therapsids were
fairly dominant in the Permian. After some confusion, dinosaurs took
over until the K/T event. Then therapsids came back. What else ya got?
John Harshman
> uraniumc...@yahoo.com wrote:
>
>>I just finished Alvarez's book
>>
>>"T. Rex and the Crater of Doom" the title of which is a bit misleading,
>>and Mr and Mrs Rex do not appear.
>>
>>I am puzzled, however, by his poor argument that after the KT boundry
>>event the mammals were able to take over the niches (large animals)
>>that dinos had previously occupied. The question arises: Why didn't we
>>get dinos all over again? Why didn't we get large reptiles, at least?
>>Why large MAMMALS?
>>
>
>
> Do you think anybody knows the answer to this? Obviousy, according to
> the ToE, it's probably because determinism goes out the window and the
> conditions that made for the "evolution" of dinos were not present after
> they became extinct.
Obviously? No. Nobody expects the same group to evolve twice -- look up
Dollo's Law. And dinosaurs, of course, didn't become extinct. There are
around 10,000 living species.
shipmodeler1
earlier extinctions Triassic/Jurassic were not complete, so there were
still plenty of dinosaur species around to reclaim their niches. Unless
you count birds as a type of dinosaur, and some large ground-dwelling
predatory birds are known from the post-boundary eras. But I'll
speculate that by the time these large birds evolved there were many
many more large mammal species able to out-compete them: Quantity over
quality, perhaps, or perhaps advanced mammals were able to meet the
re-evolving bird/dinosaurs toe-to-toe and win out.
Also, there were some fairly large reptiles in the ages following the
dino extinction. Komodo dragons come to mind, plus if I remember right
some very large crocodile/alligator species, 40-50 feet long.
As I understand it, in general reptiles cannot compete with mammals for
the large creature niches; Komodo dragons only survive because they are
located on remote islands, for example. The very broad picture would be
that primitive mammals out-competed reptiles, then dinosaurs nearly
swept the board until they went extinct, when the mammals took over
again.
Of course, we don't know for certain that there were no large mammals
livings alongside dinosaurs -- we just haven't found any evidence so
far.
Stile4aly
NashtOn wrote:
> uraniumc...@yahoo.com wrote:
> > I just finished Alvarez's book
> >
> > "T. Rex and the Crater of Doom" the title of which is a bit misleading,
> > and Mr and Mrs Rex do not appear.
> >
> > I am puzzled, however, by his poor argument that after the KT boundry
> > event the mammals were able to take over the niches (large animals)
> > that dinos had previously occupied. The question arises: Why didn't we
> > get dinos all over again? Why didn't we get large reptiles, at least?
> > Why large MAMMALS?
> >
>
> Do you think anybody knows the answer to this? Obviousy, according to
> the ToE, it's probably because determinism goes out the window and the
> conditions that made for the "evolution" of dinos were not present after
> they became extinct.
I would say that the big honking asteroid impact that occurred at the
KY boundary probably led to different conditions.
John Harshman
> I believe the reason we did not get more dinos again is because the
> earlier extinctions Triassic/Jurassic were not complete, so there were
> still plenty of dinosaur species around to reclaim their niches. Unless
> you count birds as a type of dinosaur,
Why "unless"? What prevents you from counting birds?
[snip]
George Cleveland
>uraniumc...@yahoo.com wrote:
>> I just finished Alvarez's book
>>
>> "T. Rex and the Crater of Doom" the title of which is a bit misleading,
>> and Mr and Mrs Rex do not appear.
>>
>> I am puzzled, however, by his poor argument that after the KT boundry
>> event the mammals were able to take over the niches (large animals)
>> that dinos had previously occupied. The question arises: Why didn't we
>> get dinos all over again? Why didn't we get large reptiles, at least?
>> Why large MAMMALS?
>>
>
>Do you think anybody knows the answer to this? Obviousy, according to
>the ToE, it's probably because determinism goes out the window and the
>conditions that made for the "evolution" of dinos were not present after
>they became extinct.
How does that make "determinism" go out the window?
It would seem to me that if the planet was cleared of most species of
land animals, then the ones that were left would be the ones to fill
the empty niches. In this case that would have been birds and mammals.
Its also possible that dinos were being out competed by mammals before
the KT event, since according to my reading the number of species of
dinosaurs were already in decline before the impact.
g.c.
fragallrocks
taking over from the other plants. The flowering plants had a quicker
generation time which allowed them to evolve faster. The dino's with
there generally large size and therefore long genereation time could
not keep up and the asteriod was the last straw. The smaller dino's
where then pushed out by the more adaptable mammels which all ready had
the small size ecological niches tied up.
uraniumc...@yahoo.com
Birds branched off from dinos long before this!
Ken Shaw
Whether a plant flowers has no relation to its generational length.
Why faster reproducing plants would be a problem for large dinosaurs is
also more than a little vague.
Ken
P.S. A longer reply seems to have vanished into cyberspace so if two
posts show up my apologies.
John Harshman
Second try:
None of this is true. Recent studies show that dinosaurs were at a
diversity peak just before the K/T extinction. Flowering plants have no
quicker a generation time than any other plants. Flowering plants had
nothing to do with dinosaur extinction. The smaller dinos (other than
birds) became extinct during, not after, the K/T event. There is no
evidence that mammals are more adaptable than dinosaurs. Mammals didn't
have the small size niches tied up, since there are many thousands of
species of small reptiles, amphibians, and birds.
John Harshman
Second try:
I'm not sure what your point is supposed to be. You might as well say
that tyrannosaurids branched off from dinos long before this. Because
both birds and tyrannosaurids are subgroups of Dinosauria. The only
reason we ever separated birds from dinosaurs, and not tyrannosaurids,
is that there are living birds. Look up "cladistics".
Anyway, birds are dinosaurs. All living dinosaurs are birds. But they're
dinosaurs too, in the same way that whales are mammals too.
fragallrocks
>Whether a plant flowers has no relation to its generational length.
Yes it does. Cones take three years to go from first bud to seed whilst
flower plants (angiosperms) can have generations every year or more.
The Cycads that were then the main organism in the tree niche had a
slower generation time (due to size).
The fact that the plants have a shorter generation time means that they
adapt quicker. If you study dino's you will see that they begin to
adapt (changes to the gulit etc) but the numbers are reducing as the
flowering plant number increase.
John Harshman
Very silly. You have forgotten that trees take many years after
germination before they are ready to set any seed. That eliminates any
difference between cycad and angiosperm generation times, for trees at
least. And there are plenty of other seed plants that don't take a long
time for cones to form.
DougC
uraniumcommittee wrote:
> I am puzzled, however, by his poor argument that after the KT boundry
> event the mammals were able to take over the niches (large animals)
> that dinos had previously occupied. The question arises: Why didn't we
> get dinos all over again? Why didn't we get large reptiles, at least?
> Why large MAMMALS?
I doubt that there were any large mammals co-existing with large meat
eating dinosaurs. After the KT boundry extinction, once the little
agile mammals developed a taste for dinosaur eggs, the age of reptiles
would not make a comeback. Thereafter the small mammals took a long
time to evolve into large mammals.
Doug Chandler
Kermit
It's a chaotic situation. While we could predict large, prarie,
grass-eating grazers, it would be difficult to predict which species
exactly would give rise to them.
Not only was the physical environment and the climate somewhat
different than the eco-history that gave rise to the creataceous
dinosaurs, but the "starting line" species were very different. Plants
were, too. Flora and fauna adapt not only to the climate and terrain
but also other species and *their adaptations.
It's rather like asking "why didn't the Roman Empire rebuild after the
dark ages?". It's not clear that it would happen again even if we
*could back up the clock, so to speak, and start over. There's
certainly no reason to expect either history or evolution to produce
the same results given very different conditions.
Kermit
Noone Inparticular
What he said.
Seriously, I was going to chime in even though several other posters
hit on the theme, but Kermit says it exactly right. We will never know
exactly why large reptiles (excepting crocodilians and some monitor
lizards) didn't arise after the loss of most dinosaur lineages, but
this illustrates very nicely the very important role contingency plays
in evolution. Initial conditions have a very big impact on outcomes in
many phenomena ranging from the evolution and radiation of new species
following an extinction event to the development of human society.
> Kermit
John Harshman
I take exception to "large reptiles". It makes little sense to equate
theropods with lizards and crocodiles. The question should be why
*theropods*, specifically, didn't reclaim the large carnivore niches
they had occupied before the extinction. Obviously, there's no reason to
ask why the dinosaurs didn't reclaim the large herbivore niches, there
being no herbivorous dinosaurs left at that point. In that particular
race, mammals had a big head start.
And of course theropods did have some success as large carnivores. It
may have happened almost immediately, depending on what
gastornithids/diatrymids actually ate. But whatever, it didn't stick.
Speculation is fun.
Walter Bushell
"fragallrocks" <fragal...@hotmail.com> wrote:
I've heard it was the poisons the flowering plants could make, that done
the dinos in. Plants specialize in chemical defense. Maybe the liver of
mammals was superior?
--
"The power of the Executive to cast a man into prison without formulating any
charge known to the law, and particularly to deny him the judgement of his
peers, is in the highest degree odious and is the foundation of all totali-
tarian government whether Nazi or Communist." -- W. Churchill, Nov 21, 1943
Ken Shaw
fragallrocks wrote:
> Ken Shaw wrote:
> >Whether a plant flowers has no relation to its generational length.
>
> Yes it does. Cones take three years to go from first bud to seed whilst
> flower plants (angiosperms) can have generations every year or more.
> The Cycads that were then the main organism in the tree niche had a
> slower generation time (due to size).
Wrong. Ever heard of a fern? There were plenty of other annuals that
aren't angiosperms as well.
>
> The fact that the plants have a shorter generation time means that they
> adapt quicker. If you study dino's you will see that they begin to
> adapt (changes to the gulit etc) but the numbers are reducing as the
> flowering plant number increase.
I do study dinosaurs and you are simply wrong. First off we have next
to no information about the confirmation of dinosaur internal organs.
Secondly studies from beyond the upper great plains formations have
shown that the loss of dinosaur species' diversity there was a
loclaized phenomena.
Ken
Noone Inparticular
You're quite right. I didn't put it right mostly because I am an
immunologist without the kind of training that many biologists who
study evolution have. So I munged the paleobiology. Still, I think what
kermit wrote (which in a temporal sense was a paraphrase of what you
and a few other wrote earlier) is right on the money - likely
contingency is the explanation behind the answer to the OP's question.
>
> And of course theropods did have some success as large carnivores. It
> may have happened almost immediately, depending on what
> gastornithids/diatrymids actually ate. But whatever, it didn't stick.
>
> Speculation is fun.
Yep. I read somewhere that the most exciting phrase in science isn't
"eureka" it's "....that's funny". Don't know who said that.
Pip R. Lagenta
...in the same way that Tyrannosaurus branched off from dinosaurs.
That is to say, a bird is a dinosaur in the same way that a
Tyrannosaurus is a dinosaur. You can do this for any pair of
bird/dinosaur: "chickens branched off from dinosaurs in the same way
that Brachiosauruses branched off from dinosaurs." The branch does
not fall very far from the tree. Birds are dinosaurs.
>
--
內躬偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,
Pip R. Lagenta Pip R. Lagenta Pip R. Lagenta Pip R. Lagenta
�虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌
-- Pip R. Lagenta
President for Life
International Organization Of People Named Pip R. Lagenta
(If your name is Pip R. Lagenta, ask about our dues!)
<http://home.comcast.net/~galentripp/pip.html>
(For Email: I'm at home, not work.)
uraniumc...@yahoo.com
John Harshman wrote:
>
> None of this is true. Recent studies show that dinosaurs were at a
> diversity peak just before the K/T extinction. Flowering plants have no
> quicker a generation time than any other plants. Flowering plants had
> nothing to do with dinosaur extinction. The smaller dinos (other than
> birds) became extinct during, not after, the K/T event. There is no
> evidence that mammals are more adaptable than dinosaurs. Mammals didn't
> have the small size niches tied up, since there are many thousands of
> species of small reptiles, amphibians, and birds.
Precisely my point!
uraniumc...@yahoo.com
Not exactly. They're birds.
John Harshman
And they're dinosaurs too. This is really a very simple concept. What if
Pip had told you that whales are mammals? Would you have replied "Not
exactly. They're whales."? It's only tradition and the accidents of
extinction that led early taxonomists to makes Aves a class and
dinosaurs a part of a different class, Reptilia. Fortunately, those bad
old days of confusion are gone, and modern taxonomists show Aves as a
group within Dinosauria.
Necessarily, if our classifications are to mirror phylogeny, we must
have groups within groups. Birds are theropods, and dinosaurs, and
archosaurs, and amniotes, and tetrapods, and sarcopterygians, etc. One
does not preclude the others.
John Harshman
uraniumc...@yahoo.com
John Harshman wrote:
> >
> > Not exactly. They're birds.
>
> And they're dinosaurs too. This is really a very simple concept. What if
> Pip had told you that whales are mammals? Would you have replied "Not
> exactly. They're whales."? It's only tradition and the accidents of
> extinction that led early taxonomists to makes Aves a class and
> dinosaurs a part of a different class, Reptilia. Fortunately, those bad
> old days of confusion are gone, and modern taxonomists show Aves as a
> group within Dinosauria.
>
> Necessarily, if our classifications are to mirror phylogeny, we must
> have groups within groups. Birds are theropods, and dinosaurs, and
> archosaurs, and amniotes, and tetrapods, and sarcopterygians, etc. One
> does not preclude the others.
Dinosaurs as a group are extinct. Birds are different from dinosaurs as
a group. 'Dinosaurs' is a smaller group that does not include modern
birds per se, just as 'whales' does not include 'bovines'. Manatees are
not whales, even though manatees and whales may have a common ancestor.
We use different terms because the features of birds are different from
dinos.