Of course I don't want to take up your time, and I understand if you don't respond. But I would be very interested in a recent reference, electronic or paper.

Grant Hutchison

Nature 334: 665-669
Nature 375: 117-120
Nature 399:114-115
Journal of Experimental Biology 201: 1043-1050
Journal of Experimental Biology 201: 1739-1744
Biology 201: 1739-1744
Geochimica et Geophysica Acta 58: 1393-1397
Biosystems 10: 293-298
Transaction of the Royal Society of London B. 353: 131-140
American Journal of Science 289: 333-361
Science 241: 717-724
Science 287: 1630-1633
Paleogeography, Paleoclimatology, Paleoecology 75: 223-240
Philosophical Transactions of the Royal Society of London B. 353: 131-140

There are more, but it is too much like work.

Nick Lane lays out the basics in Chapter 5 of his wonderful book, Oxygen: The Molecule that Made the World. Highly recommended reading.

http://www.nick-lane.net/Extract%20chapter%205.html

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Lol. The last few exchanges have been funny. Impressive too. An odd combination.

Yes, thanks, I've read it, and I would echo your recommendation.
I just pulled it off the shelf, and I see that his reference list handily overlaps yours, to a large extent.
He helpfully gives full titles and dates, so I'm seeing that your list mainly involves publications from the 1990s, dealing with an assortment of oxygen-related things: plant adaptations to fire, the flight of Carboniferous dragonflies, K-T impact effects, polar gigantism, and some of Robert Berner's older work using gas bubbles trapped in amber. Nothing so far jumps out at me as being both relevant to Mesozoic oxygen levels and up-to-date.

Are you aware of anything more recent, specifically countering Berner's 2005 model?

Grant Hutchison

Grant, we've gotten your input on our takes. What are your feelings on the original article itself and the conclusions reached?

I too have them on my shelf and I echo Grant's sentiments. Since I live in the U.S. I am most familiar with what J. W. Powell would call the Arid Lands of the western part of the country. The most striking thing to me is that during the Mesozoic an amount of sediment that was laid down, with interruptions, prior to the Tertiary uplift that was simply enormous. A sea stretching from the Gulf of Mexico to the Arctic waxed and waned while there were no ice caps. Vast coal seams formed during times of anoxic swamp deposition. Some even preserved dinosaur footprints that were discovered when the coal was removed and casts in clay and sand sediments were seen on the ceilings of the mine tunnels. We are talking about a time period of +- 185 million years. Through the geology of those sediments now exposed are clues to the past climate, but probably not with a resolution that we might find satisfying. To sort of all those years of ebb and flow with all the potential variables will suffice to employ an army of humans discerning one clue at a time and then to put the puzzle pieces together, more time. Berner's work is a good start, but I am certainly hungry for more.

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

I think Sato probably hasn't been best served by journalists. I find it very difficult to make out what he actually said, even after Googling up a number of versions of the story and reading the paper version in New Scientist last night. So far I haven't been able to find an on-line transcript of his original presentation.
The "couldn't fly" and "couldn't soar" headline recurs on-line, but that doesn't seem to accurately reflect the reported content. Sato apparently telemetered the flapping frequency of various free-living albatrosses, and has come up with some sort of rule of thumb involving wing length, flap frequency and weight. He has made some sort of extrapolation to pterosaurs, and has commented on their potential ability to flap in order to take off and stay aloft in still conditions, comparing it unfavourably to albatrosses.
Was this just a throw-away comment at the end of a presention about albatross telemetry? Or was it a careful presentation centred on pterosaurs, taking into account differences in anatomy, and discussing potential differences in physiology? I find it impossible to say, from the reports I've read. It also seems quite outlandish for the comics to run with headlines about "couldn't fly" or "couldn't soar", when all the guy seems to have said is that pterosaurs wouldn't perform at all well in flapping flight. That's a statement about limited flight options, not about an inability to fly or to soar.

So I suspect the poor fella is pretty hacked off with his news coverage, at present.

Grant Hutchison

So, Sato didn't approve that message....

Good work Grant.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

Yep. Happens a lot though. Shock headlines sell unfortunately; just look at this thread.

Well, I don't know that. All of the above was just me trying to understand what the heck the back story is. And it looks to me very much as if Sato is being done a disservice. But if you want to judge for yourself, Google on "Katsufumi Sato" and "pterosaur", and sample the journalism available. Sato was presenting at the Biologging Science Symposium. From the meeting description (in the link), it seems fairly probable that he was primarily presenting his albatross telemetry. But as I say I haven't found a transcript.

Googling around, it's interesting to see how many comments this story attracts from people who mention giant dragonflies. But those dragonflies flourished in the Carboniferous, as long before pterosaurs as T. rex is before the present day. From Berner's data, the Carboniferous was a period of high oxygen partial pressure, which persisted until the time of the end-Permian extinction event. That's when the evidence of anoxic oceans and soils begins to appear, suggesting a huge change in atmospheric chemistry. So we can't reasonably cite the existence of giant dragonflies as an example to support better flight performance in pterosaurs: the two groups never co-existed, and they inhabited very different worlds.

Grant Hutchison

Grant Hutchinson, you seem to be an expert, so I have an amateur question for you, hope you don't mind. It's something I've always wondered

Why was everything so much larger back then?

Thanks

Atmospheric density fails as an explanation because of the long time period involved in their existence through the Mesozoic and would not have been consistent during their evolution into different ecological niches. They were successful marine predators as were the avians that they coexisted with. The more interesting question to me is that since they occupied similar niches with the birds, why did they fail to survive the end Cretaceous as the birds obviously did.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

In my part of the world are numerous bird species who thrive in their cliff face environment. Sea birds of various kinds. Back in the good old days (centuries and millenia ago), clambouring about the cliffs in search of their eggs was always a good way to get yourself killed.

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I offer a complete and utter retraction. The imputation was totally without basis in fact, was in no way fair comment and was motivated purely by malice. I deeply regret any distress that my comments may have caused you or your family, and I hereby undertake not to repeat any such slander at any time in the future.

Nice analysis, Grant.

I am pretty sure I remember seeing a picture of an ichnofossil of purported pterosaur tracks in sandstone, waters edge. Ah yes, Wellnhoffer, Pterosaurs, page 158.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

Luckily there seem to be a lot of experts. So I'm throwing it open. Anyone?

In the Triassic the Rhamphorhynchoidea Family were the first and they were sparrow sized and up. They went extinct at the Jurassic Cretaceous extinction event. The Pterodactyloidea arose during the upper Jurassic and were generally larger but there are examples of smaller forms. These animals are reptiles and it is a feature of reptiles to grow throughout their life but the evolutionary trend is definitely to larger species until their demise. All I can say is the cliche that there must have been an evolutionary advantage to do so.

In my imagination seeing Quetzalcoatlus with a thirty five foot wingspan fly close over my head would make me duck.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

Thanks jlhredshift.

How about everything else though? Huge dinosaurs, huge dragonflies, huge ferns? Any idea?

Higher temps? Higher CO2? More sunlight?

It's a popular misconception.

The dinosaurs were actually quite small.

But when the Expanding Earth grew, the fossilized bones grew too.

Ok, I cast my vote with more oxygen and evolutionary advantage in size.

More sunlight, no.

As has been pointed out before the Carboniferous was a different setting climatologically than the Mesozoic. Arthropods absorb oxygen through their exoskeleton and therefore large forms can only be supported in higher oxygen environments. The lack of these large arthropod forms indicates lower oxygen levels.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

The Mesozoic also supported huge, land, life-forms, correct?

Would it be a better question to ask why our current period is the only one that doesn't/hasn't?

Thanks

Elephants ain't exactly small.

Not me. I just like to present a well-documented argument.

Well, everything wasn't. We just hear about the big stuff because it's exciting. But almost all life, always, has been considerably smaller than a human.
The big arthropods seem to correlate with high oxygen, and disappeared when oxygen levels fell. IIRC, we've got the biggest marine life ever living on Earth at the moment. As to why the dinosaurs produced particularly big land animals, I haven't a clue.

Grant Hutchison

The current period, the Cenozoic, is 65 million years long. But, as the mammals evolved from smaller forms that had survived the K/T they did grow to larger forms:

Source

And of course in recent times the Wooly Mammoth

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

Oooof. More confused than ever.

Totally my fault for asking a 'Life, the Universe and Everything' type question

Thanks for your answers though guys. It seems to be a case of a) partly observer bias and b) not much difference in the first place. Hope I got that right...

Same for me, but Grant does a better job.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

It seems like, for coldblooded animals you'll have an evolutionary advantage in size, as skin heat loss is lower the bigger you get.
If you have some heating from the metabolism, keeping heat in will can more important than absorbing it fast from outside and big size becomes a definite survival trait.

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‘To those who regard “crime fiction” as some sacred icon which must follow a rigid formula, I will always be the man who writes 18-syllable haiku.’Trying to make sense of computers, The Error Log.

Hmmm... How many of the dinosaurs were cold blooded?

From Wiki

I realize this is a long quote, but it goes directly to the point.

__________________
(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"