h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

http://www.bbc.co.uk/h2g2/guide/A565733

Hello there,

This is my first effort at a guide article, all responses welcome. Ibelieve it is, in essence, complete. It describes the evidence for both sides of a debate that has been current for at least a century. The debate in question is whether Dinosaurs were warm-blooded or cold-blooded.

I am not sure whether the content is pitched at the right level but I will listen to the more experienced among researchers to let me know.

Many thanks,

Cestus

Hi! Just wanted to stop by and say that I think this is a really interesting, apparently well-researched entry. My biggest suggestion would be that you break up the text in the historical perspective section -- that paragraph is just *way* too long....

Mikey

Mikey,

Many thanks for taking the time to read my piece. I have broken up that paragraph as you suggest and it does make the article more readable. I will try to remember this for future pieces as well

Cheers,

Cestus

I really, really like this entry. My Significant Other has a deep interest in dinosaurs and has forced, sorry 'encouraged' me to read widely on the subject. This seems like a good summary of the evidence for dinosaurs being warm-blooded. I'd say it definitely deserves its place in the edited Guide if it were up to me.
Now to be picky, your final footnote probably isn't terribly enlightening, just one technical word substituted for another. If it's important enough for you to want to add, maybe you could explain more gently what Deinonychus is.
Being even more picky, in the last paragraph of your historical perspective section you've got a capital letter following a semi-colon. I think this is not right.
Otherwise, excellent work.
MC

I like this article but have two reservations about it.

1. You use the term endotherm and ectotherm throughout it. I know these are the technical terms, but I find them confusing and unfamiliar. Would it detract from the article if the terms cold-blooded and warm-blooded were used? These are familiar to many people. I know they are not quite accurate, since cold-blooded animals have warm blood which is warmed by external means. Nevertheless, they are the normal terms.

2. You say that the article is not going to answer the question, then you present overwhelming evidence in favour of warm-bloodedness and say that most palaeontologist support it. Why not just present this as the current view and mention that not all palaeontologists agree at the end. Leave out the statement about this article not answering the question.

I agree with Gnomon on both points. While you could just define ectotherm and endotherm as cold-blooded and warm-blooded in the beginning, ectotherm and endotherm are similar enough looking and sounding words that it's reasonable to assume that your average lay person will confused relatively quickly.

Just my 2 cents...


Mikey

Folks,

Once again, many thanks for your time and kind words.

MC : I agree with you entirely, I have modified the footnote, initially I was wondering how to provide a good description, then I remembered Mr. Spielberg's contribution to the canon

I have added more to the Hadrosaurus footnote for the same reasons.

Gnomon : You're right of course, there really isn't any need to reuse the terms once they've been defined at the beginning, I will update acordingly.

Actually the reason I stated I was unwilling to answer the question is twofold:

I felt it would smack of providing my opinion rather than an impartial examination, I'm not sure if such a thing is considered appropriate.

I also believe that the question remains open. Science is a funny thing. There is work on-going at the moment to evaluate the oxygen density during the Jurassic. If the density is found to be dramatically higher then the current levels then the state of understanding could change. I believe that no significant changes will occur but again that's my opinion

Mikey : I'm on it, there will be a modified version published soon.

Thanks again,

Cestus

Update now made

Cestus

All I can say is I like what youve done with tis article. I feel it has a place in the guide.

Maybe there are other entries/sites you can link to?

There don't appear to be any articles covering the same kind of area in the guide yet, I have added a link to Dinosauria Online, absolutely the best web resource on the suject.

Thanks for the suggestion.

Cestus

Hi, brilliant article!

Point 9 (i think) of yur evidence in support of warm bloodedness. Fish live in the antarctic today and are cold blooded are they not?

Orcus,

Thanks for pointing that out. You're quite right, actually fish are in a rather fortunate position as they are functionally adapted to operate ectothermically without ready access to 'basking'. I should have made it clearer in the article that I was referring to terrestrial animals.

Update to follow

Cestus

I have changed the paragraph and a typo.

Cheers,

Cestus

Yeah, looks good!

Well, sooner or later there will be a scout coming by and drop a very nice note, which will start with the headline 'Congratulations'. Don't worry! It's only lasting and lasting because weeks only have 5 working days and there are only 5 entries per day to be picked.

*sshhhhh*

*whispers*

I've just been picked as a scout - and I will pick this unless someone baets me to it

Not official yet but I had the offer today

If the mean ambient temperature was much higher shouldn't that mean that it was much more viable to maintain ectothermic activity even at night, and conversely, wouldn't the energy expenditure for endothermy be reduced?

Bossel.......,

Many thanks for the reassurance, it is much appreciated, nervousness does start to set in after a while........

Orcus,

Wonderful, thank you, how kind

Mycroft,

There just had to be one didn't there.........

There is a great deal that isn't certain about the environment in the Mesozoic, we know it was different, we're not sure how different.

There is an entirely valid point here, the question is whether the conditions were different enough to permit ectothermy to prosper in gigantic animals. I feel that the conditions probably weren't sufficiently different by the end of the Cretaceous to make ectothermy viable, I'm not so sure about the mid-Triassic. I have some sympathy for the notion that the smaller predatious dinosaurs of the late Triassic were rather less endothermic than their descendents and therefore that increased endothermy may have been a gradual response to gradually changing conditions over a period of 100 million years or so. I think that the fossil evidence points to a much more sudden swing in the Triassic, but again that's an opinion.

I've tried not to let my views influence the piece too strongly so I would be unlikely to include such a discussion in the article until new evidence appears to support one side or the other.

There are other discussions of interest. For example, Peter Dodson has clearly found very good evidence that many, if not all, of the Ceratopsia (principally Cretaceous animals, towards the later Mesozoic) may have sprawled their front legs, in the manner of a lizard, rather than stand in a more columnar fashion. If that is so, we must wonder why, and if their metabolism was in some way different to other species at the same time. These are speculative, though.

Mean ambient temperature was certainly higher at some points in the Mesozoic, it may well have been higher throughout, this would have an impact on the 'maths' of ectothermy. There is no current evidence to sugest that it was high enough to permit three ton Allosaurs to charge around the freezing pole however. It is possible that the dinosaurs in such conditions hibernated, speculation again. I do not believe that endothermy is like switching on a light, there are degrees of warm-blood, perhaps it was possible for animals in some areas to be more warm-blooded than in others, generally more massive animals use a lower proportion of their energy to heat their systems, so maybe Brachiosaurus was as ectothermic an endotherm to ever walk the planet.

I await developments with baited breath

All the best,

Cestus

Don't hold your breath for me
I can't make any picks for quite a while yet but you never know - further scouts may be amenable

Hmm... was it the north or south pole that had allosaurs roaming around? According to my maps Antarctica has been close enough to the South pole to have glaciers there permanently for at least 300 million years. If that's the case and dinosaurs were having snowball fights down there then why hasn't anyone spotted a frozen one yet?

I would guess that glaciers' movement would take ice from the centre of the continent into the sea in rather less than 300 million years.