Subject: Re: [Palaeoology] Croc eggs sometimes soft
Hard eggshells likely evolved for different causes. I think john is refering to that paper by our friend, where he points out that hbirds evolve hard eggshells because the lungs cannot be squash...The question here also is why birds reduce the eggshell's unit and incorporate two to three layers on the top of it?
Speaking as a bird and reptile embryologist and incubationist of 25 years standing... since when has the hard shell been there to stop the lungs being squashed?
> Hi, > > I think we should send an email to David and his > team explaining it...
Good idea! I've read Lala's posting (for which, thanks Lala) which agrees with Charles'. It seems that the filmmakers did, as I mentioned in my last posting on this, carefully remove all traces of the hard shell.
The only thing that concerns me now is why bother having hard shells at all? If hard shells are there to prevent the lungs being squashed, as seems to be the case with birds, why allow the hard shell to become incompetent in the final stages of incubation? Perhaps croc's lungs are not so vulnerable, or perhaps not in the final stages.
Cheers,
John J
PS - I wish I was back in one of my "no TV" times. Boring but so much more productive!
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Thank you very much for Kenneth Carpenter that after months of searching has located a the paper below...If anybody would like a copy...Just frop me an email! ...
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... Good idea! I've read Lala's posting (for which, thanks Lala) which agrees with Charles'. It seems that the filmmakers did, as I mentioned in my last ...
... Maybe the filmmakers removed much of the hard outer shell leaving only the inner membrane for us to see. ... I'd be very interested to see what you think...
Speaking as a bird and reptile embryologist and incubationist of 25 years standing... since when has the hard shell been there to stop the lungs being...
Hard eggshells likely evolved for different causes. I think john is refering to that paper by our friend, where he points out that hbirds evolve hard eggshells...
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