Quote:
In reply to grant hutchison's comment: I think the discussion of footprints is missing a couple of important considerations:
1) Deep footprints in soft ground rebound: there's a hydrostatic effect which makes the base of the footprint rise when the weight is withdrawn.
2) Fossilized stuff gets squashed. As a thick moist layer turns into thin dry layer, the relief of any footprint is going to be reduced.
What we're reading is a poorly considered polemic, rather than science.
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Grant,
Have you read Wilson's "Evolution for Everyone"?
http://www.google.ca/url?sa=t&source...Tv6HISQXdC7P6Q
Shouldn't there have been an evolution advantage to limit the size of the animal?
Your comment concerning the fossil footprint record makes sense to me. (i.e. That there should be some sort of rebound in the ground, so the depth of the footprint fossil may not necessarily prove anything.) But I am thinking about the difficultly an 80 ton animal would have to walk through different terrain.
The writers are not anti-creationists. They are not saying sauropods did not exist. They are saying something was fundamentally different in the environment when gigantic animals and plants thrived which which partially removed a limit to gigantism.
Look at each claim individually.
The question of blood pressure and the length of the sauropod neck is interesting. Pressure is mgh. The writer is asking the question what is the evolutionary advantage of having a long neck if sauropod will die if it lifts its neck?
The question how could a pterosaur been physically capable of flying is a believe a currently unanswered question. I believe wind tunnel models and a basic analysis have not resulted in explaining how such a massive large animal could have flown.
I would disagree it follows logically that as science had some difficultly explaining how a bee could fly, that it follows that a pterosaur with a wing span the same as jet could fly, all else being the same as today.
I had heard a theory that only the young pterosaurs had the capability of flying however that does not makes sense as there would be no evolutionary advantage for the pterosaur's physiology.
Christine,
You comment that there is no reason why a Sauropod's could not mate makes sense to me. It should not have been included in the writer's list of arguments. Perhaps sauropods were anatomically re-arrange to allow a different position. As soft tissue is not preserved in the fossil record, there is no data to answer a mating question.
The issue of blood pressure and the sauropod's ability to support its mass is a different question.