65-Million Year Old Mystery Resolved?

[DecayingAngel]

I Feel The Same

I'm sold.

I look back on the leaps and bounds our collective knowledge of dinosaurs has grown over the last 25 years and am amazed. From thinking of them being lumbering, dim-witted long-dead beasts to nimble, feathered, their-descendants-walk/fly-among-us animals in one lifetime is enormous. Kind of like my grandparents who went from horse-drawn wagons to the Apollo missions in their lifetimes.

Michael

You have excellently summed up the wonderful advancements paleontology has made, especially when it comes to dinosaurs. Some of this is due, I think, to China now being more open and allowing scientists from other countries more opportunities to explore regions so very rich in fossils.

Funny thing--I forgot exactly who it was back in the 1800s who proposed that dinosaurs seemed to have more in common with birds than reptiles or lizards. But he was basically laughed out of the profession. How things have changed!

Have to wonder what the future holds regarding these marvelous animals, and how much more knowledge about them awaits us.

Sharon (who never "outgrew" her fascination with dinosaurs and other prehistoric beasts)

 

[shadron]

Really? Nobody sees the silliness in science like this being decided by vote?

And, why does it matter?

Hypothesis: big rock hits earth, math of the physics follows, result... big trouble in little china. Check. thumbs up, good science.

Hypothesis: Dinosaurs existed, evidence of bones, tracks, etc. Proposed dating techniques that likely put it in a range of a really long time ago. Check, pretty good science. OK.

Ditto, dinosaurs cease to exist at some time. OK

Good possibility that one caused the other, OK. But why do you need to tell me this? And why does it need to be elevated beyond so simple a statement? Why does science need a college of cardinals?

IE
When you make a conclusion without a complete record or a complete slate of evidence, what is likely to happen to the effort to collect evidence?

What is gained by jumping to the conclusion (even if the gap is only two feet)? When did the voting step get added to the scientific method?

"...and why am I asking you?"

 

[MG1962]

You have excellently summed up the wonderful advancements paleontology has made, especially when it comes to dinosaurs. Some of this is due, I think, to China now being more open and allowing scientists from other countries more opportunities to explore regions so very rich in fossils.

Paleontology also has another excellent advantage. The data and the evidence never gets destroyed. As each new piece of technology and investigative tool is developed it can be aplied retrospectively to old finds.

And sometimes discoveries come from the oddest places. The actual locomotion of the bigger dinosaurs had been a bit of a mystery. During the preproduction of Jurrasic Park one of the CGI guys was watching film of an ostrich running (convinced the joint system was similar) When he ran the film backwards he discovered a whole new form of movement

He showed the film to some paleontologists who apparently had lightbulbs going off all through their heads - then suddenly how a 100 ton beast on two legs could move 25 miles an hour was understood

 

[geni]

Paleontology also has another excellent advantage. The data and the evidence never gets destroyed. As each new piece of technology and investigative tool is developed it can be aplied retrospectively to old finds.

Nope we've lost stuff over the years. Sometimes due to poor record keeping (do you really know what is in all those boxes in the cellars?) theft (fossiles are valuable), physical damage (from straightforward handleing to more serious issues) and other record keeping issues (how sure are you as to where stuff came from?).

 

[fuelair]

You have excellently summed up the wonderful advancements paleontology has made, especially when it comes to dinosaurs. Some of this is due, I think, to China now being more open and allowing scientists from other countries more opportunities to explore regions so very rich in fossils.

Funny thing--I forgot exactly who it was back in the 1800s who proposed that dinosaurs seemed to have more in common with birds than reptiles or lizards. But he was basically laughed out of the profession. How things have changed!

Have to wonder what the future holds regarding these marvelous animals, and how much more knowledge about them awaits us.

Sharon (who never "outgrew" her fascination with dinosaurs and other prehistoric beasts)

Welcome in!! I 'spects you will have fun here!!

 

[Fnord]

Really? Nobody sees the silliness in science like this being decided by vote?

And, why does it matter?

Hypothesis: big rock hits earth, math of the physics follows, result... big trouble in little china. Check. thumbs up, good science.

Hypothesis: Dinosaurs existed, evidence of bones, tracks, etc. Proposed dating techniques that likely put it in a range of a really long time ago. Check, pretty good science. OK.

Ditto, dinosaurs cease to exist at some time. OK

Good possibility that one caused the other, OK. But why do you need to tell me this? And why does it need to be elevated beyond so simple a statement? Why does science need a college of cardinals?

IE
When you make a conclusion without a complete record or a complete slate of evidence, what is likely to happen to the effort to collect evidence?

What is gained by jumping to the conclusion (even if the gap is only two feet)? When did the voting step get added to the scientific method?

I see the Cynics have appointed a new ambassador.

 

[samm]

I see the Cynics have appointed a new ambassador.

And we come in peace.

Now, please take me to your wise men...

 

[Delvo]

I thought this was pretty much settled as well. I didn't know there were any holdouts on the issue. Is there an alternate theory?

The main alternate theories have been a vast Earthly volcanic event such as the Deccan "traps", and routine natural selection at work throughout ecosystems as it always is.

The latter is, after all, the cause of most extinctions that have happened, since most extinctions did not happen during mass extinctions. The category can include diseases that they failed to adapt to, changes in food supply that they failed to adapt to, and tougher new competitors or predators that they failed to adapt to. The usual culprits in one way or another (other than fellow dinosaurs and their diseases, suddenly introduced when continents collided) are mammals, birds, and flowering plants. None of those were totally new at the time, but they had recently undergone important developments and were in the process of rapidly diversifying and increasing their ecological presence and importance.

I don't think anybody has said in recent years that no comet impact happened, since the iridium layer is pretty unavoidable and not really subject to alternative interpretation. But some were saying that it either made no net difference or only nudged the world into more quickly undergoing changes that it would have undergone anyway. Their focus is not so much on whether the impact happened, but in why it should change the big picture biologically; why would the same groups that dominated before not continue to after? The two main questions they would debate the answers to are how equally or unequally such an event would be expected to affect different groups (why would it hit some harder than others), and to what extent the survivors survived not because of luck or even serendipitous pre-adaption to immediately-post-impact conditions, but because they had certain advantages over other groups that were already in the process of gaining them the upper hand anyway.

I thought one of the reasons that other causes were thought to have had an important impact on dinosaur extinctions was that the extinctions took place not all at once but actually over the course of millions of years, starting several million years before the K/T boundary. Which suggests that there was something else going on other than just an asteroid impact, and that the impact may have simply finished things off given an already weak ecology.

I've seen an article by a statistician explaining how he believed that this was an illusion that can happen in any data set that suffers a sudden crash in diversity, making it appear to non-statisticians as if diversity had dwindled before the crash even though it really didn't. (Basicly, the way it works is that there are always some background fluctuations, extinctions that happen anyway with or without a large-scale event, but you can't see the ones that would have happened after the crash because of how everything changed at that point, whereas you do still see the ones that happened shortly before the crash.) I can't point to where I saw that, though.

 

[BenBurch]

Nope we've lost stuff over the years. Sometimes due to poor record keeping (do you really know what is in all those boxes in the cellars?) theft (fossiles are valuable), physical damage (from straightforward handleing to more serious issues) and other record keeping issues (how sure are you as to where stuff came from?).

And some testing is destructive.

 

[pchams]

And we come in peace.

Now, please take me to your wise men...

I see your point. It's very basic in science.
Consensus != fact

Why anyone here would debate that is beyond me.
What can be debated is what I guess they call in the civil court "preponderance of evidence".
If it is so overwhelming then we can use Sagan's dragon in the garage example.
If there is some evidence that the dragon may be a lizard, then we may well not dismiss it at hand.

To take any scientific question to council for proclamation is idiocy.

 

[Cainkane1]

According to this MSNBC article, the debate over cause of the mass extinction of the dinosaurs is settled.



I'm sold on the idea. Anyone else?

http://www.chick.com/reading/tracts/1038/1038_01.asp

nah that ain't what happened this did.

 

[casebro]

So, when is the next one due?

 

[The Central Scrutinizer]

According to this MSNBC article, the debate over cause of the mass extinction of the dinosaurs is settled.



I'm sold on the idea. Anyone else?

Well, given that the Earth is only 6000 years old, I'd say no.

Fools!!!

 

[The Central Scrutinizer]

so, when is the next one due?

Dec, 2012

 

[ZirconBlue]

I thought the dinosaurs all died from getting stuck in tar pits.

 

[Miss_Kitt]

There is no attempt to settle the issue here, gentlefolk. What is going on is a discussion of an ongoing debate in paleontology.

Based upon what I have read, I think the asteroid event was the coup de grace on a (relatively) fragile ecosystem. Deccan (volcanic emissions) played a role; and the opportunity for population overlap and serious impacts from disease and parasites looks promissing as well. With the sparsity of the fossil record, we are probably never going to have a definitive answer.

There appears to have been a decline in the number of species, which puts the system at risk from any sudden disruption, physical or biological: Fewer niches = fewer opportunities to make small adaptions that work in the new world; lower diversity = less opportunity for there to be resistance to a disease or pest. It is also true, however, that the fossil record is not even remotely a census of what the flora and fauna of a given place and time was.

For the most part, the body of fossils grows with time; the techniques for analyzing old specimens multiply; the sophistication of computer modelling improves; and the communication between groups in different parts of the world improves. All of these add up to us likely getting closer to "the truth" as time goes on.

One of the more interesting things going on in dinosaur-and-related paleontology these days is the reclassification of specimens either into new species, or out of new species into being juveniles of other species. Our ability to read the information in these old bones and impressions is growing; and one of the plusses of "Jurassic Park" is that it sparked a whole new generation to fall in love with paleontology. Any time you increase the number of bright people working in a field that relies on detailed analysis and comparison of specimens, you will gain knowledge. Any time you have a bunch of eager volunteers to go endure the tough conditions and hard physical labor of digging up and preserving fossils, you are going to gain more material to work from.

I expect our best-guess "knowledge" of dinosaurs and their kin to continue to increase rapidly for at least another decade. Some day, we will hit the inflection point of the curve for this set of technologies and ideas; then the discovery / likely hypothesis rate will flatten out again for a while. But what a pleasure and a privilege for us to be able to eavesdrop on this exciting time in one of the oldest fields in paleontology!

Now I have to go read some more, MK

 

[Kestrel]

According to this MSNBC article, the debate over cause of the mass extinction of the dinosaurs is settled.



I'm sold on the idea. Anyone else?

I found the evidence compelling after first hearing about it in 1979.

 

[ZirconBlue]

I found the evidence compelling after first hearing about it in 1979.

Gosh, you're old.

 

[DecayingAngel]

Extinctions Still A Mystery

Well put, Miss Kitt!

About that article @MSN, this is nothing "new" since both the asteroid theory and the location of the crater has been known for a while now. Don't know why this is once again noteworthy news, except that maybe more scientists have now accepted this as the cause.

However, we tend to forget that there have been other, extremely major extinctions before the one at the end of the Cretaceous. It seems most attention is focused on the dinosaurs, but the others were devastating to life in the extreme.

I'm not discounting the asteroid theory at all, but there may be something at work here that we don't yet understand:

Ordovician-Silurian
Late Devonian
Permian-Triassic (possibly the greatest extinction event of all time)
Triassic-Jurassic

It is also difficult to understand why Ammonites, which first appeared in the Devonian, were able to survive all the extinctions except that of the Cretaceous. And why did sea turtles continue to exist from the Triassic up until today?

Somewhere in here there is a pattern-but of what? To me the question is still unanswered.

So many questions, so few answers. But that's what makes scientific inquiry so exciting.

 

[quarky]

I'm still confused:

Why would the impact take out the marine dinos?
And why didn't it take out alligators and turtles?