"Squishy Joints" May Have Helped Dinosaurs Grow To Giant Sizes

benonemusic writes "A new study in the journal PLOS ONE suggests that dinosaurs reached gigantic proportions relative to mammals because of differences in their cartilage, making their joints squishier and able to sustain greater amounts of force. Other factors contributed to dinosaurs' larger sizes, including their lighter, air-sac-filled skeletons, and some researchers point out that the sizes of some dinosaurs and mammals were approximately equal, so anatomical differences between cartilage in dinosaurs and mammals may not directly explain why some dinosaurs grew to larger sizes."

Comments

Wrong question

[Joce640k]

"anatomical differences between cartilage in dinosaurs and mammals may not directly explain why some dinosaurs grew to larger sizes."

Anatomical differences are never going to explain "why", they can only explain "how".

"Why" is easy to answer - survival of the biggest.

Re:Wrong question

[Capt.Albatross]

"anatomical differences between cartilage in dinosaurs and mammals may not directly explain why some dinosaurs grew to larger sizes."

Anatomical differences are never going to explain "why", they can only explain "how".

Agreed - this is sloppy reporting (mainly in the /. summary but also in the original). I think what they are trying to say is that this particular joint design, which evolved in smaller reptiles, later proved to be helpful in the evolution of giant dinosaurs - i.e., it was a sort of exaptation (formerly known as pre-adaption) in the sense that while this design's posited suitability for carrying large loads wasn't necessary when it evolved (the mammalian design was equally capable for animals of that size), it became a decider as evolutionary forces favored gigantism.

Re:Wrong question

[Sockatume]

Given that "survival of the fittest" is an unguided process, isn't that also "how" rather than "why"?

Re:Wrong question

[xevioso]

I agree. No one says to a 6 year old when they ask "Why is the sky blue" ...

"Do you mean why as in motives or did you actually mean how it is that the sky is blue? Please clarify."

because if you ask that, then they will say, "Why"

and then you are screwed.

They smoked squishy joints too.

[Anonymous Coward]

The huge joints that dinosaurs would have rolled would be quite squishy and sticky. They lit them at volcanoes of course. Which eventually led the the dinosaurs becoming too lazy and destructive(the joints would start forest fires) to serve their alien overlords so they were killed off.

Re:They smoked squishy joints too.

[drainbramage]

And that, Ladies and Gentlemen, is why they called it the Stoned Age.

Critical thinking missing

[abhisri]

Evolutionary paths.

Insects on average are smaller than most mammals. Mammals too come in all sizes.

Analysis of air trapped in amber fossil shows that oxygen ratio in that period was higher, which may have permitted evolutionary path of such giant creatures.
http://minerals.cr.usgs.gov/gips/na/amber.html

Squishy joints? Considering how cause and effect get frequently confused, it seems more likely that the joints may have became "squishy" in order to support the larger size permitted by the oxygen-rich high-metabolism environment, not necessarily actually the cause.

Re:Critical thinking missing

[Joce640k]

Insects don't have lungs or a circulatory system. Their size is limited by how fast oxygen can diffuse through their internal goo.

Re:Um...

[jabuzz]

No some, possibly even most dinosaurs are the same size as mammals. A small number of species of dinosaurs grew to be bigger than the largest land based mammals.

It's all bogus anyway as the largest known animal to ever exist is a mammal, namely the Blue Whale.

http://en.wikipedia.org/wiki/Blue_whale