Does anybody know why some dinosaurs became bipedal?

[mistermack]

I don't recall this ever being explained, or theorised about. But maybe it has been.
Does anybody know? (save me looking it up)

[Tyrannical]

Some predators were, but most were quadrupeds I thought.

[Gawdzilla Sama]

I thought the first dinosaurs were bipedal and some became quadrupedal.

[GenesForLife]

Could something pertinent possibly be in this? http://scholar.google.co.uk/scholar?as_ ... ts=5&hl=en

I'll also search through a literature database and will try to find relevant papers later, if possible. (Institutional access rocks)

[mistermack]

I thought the first dinosaurs were bipedal and some became quadrupedal.

That appears to be right.
I would not have guessed that. But thinking about it, it's logical. They appear to have evolved from a very small bipedal animal, and grown in size from that.

I couldn't imagine how a big animal could evolve bipedality, and it seems they didn't.
Some bipedal dinosaurs went back to walking on four legs, after they got big, by the look of it.

But the big bipedal ones like T Rex started out as very small two legged creatures, and stayed bipedal as they got enormous.

Some modern lizards use bipedalism as an escape mechanism. I'm imagining that something like that happened, and flourished as a way of catching quick moving prey.
It just didn't seem likely that a big animal would evolve that way.

[GenesForLife]

I thought the first dinosaurs were bipedal and some became quadrupedal.

That appears to be right.
I would not have guessed that. But thinking about it, it's logical. They appear to have evolved from a very small bipedal animal, and grown in size from that.

I couldn't imagine how a big animal could evolve bipedality, and it seems they didn't.
Some bipedal dinosaurs went back to walking on four legs, after they got big, by the look of it.

But the big bipedal ones like T Rex started out as very small two legged creatures, and stayed bipedal as they got enormous.

Some modern lizards use bipedalism as an escape mechanism. I'm imagining that something like that happened, and flourished as a way of catching quick moving prey.
It just didn't seem likely that a big animal would evolve that way.

Citation required.

[Gawdzilla Sama]

Or we'll open fire!

[GenesForLife]

Never mind, I found a citation.

http://www.nature.com/nature/journal/v3 ... 1064a0.pdf

WE report here the discovery of a primitive dinosaur skeleton from Upper Triassic strata in northwestern Argentina. The 1-m-long skeleton represents a new taxon, Eoraptor lunensis gen. et sp. nov., which is close to the predicted structure and size of the common dinosaurian ancestor1–5. The skull, which has a unique heterodont dentition, does not exhibit any of the specializations of the major dinosaurian clades (Ornithischia, Sauropodomorpha, Theropoda). The forelimbs are less than half the length of the hind limbs, which suggests an obligatory bipedal posture. Although close in overall form to the common dinosaurian ancestor, the functionally tridactyl, grasping/raking hand and other features show that Eoraptor is allied phylogenetically with theropods. The discovery of Eoraptor supports the hypothesis that dinosaurs diverged rapidly at small body size from a common ancestor, with the principal herbivorous and carnivorous lineages present by the middle Carnian.

[mistermack]

Paleontologists believe Eoraptor resembles the common ancestor of all dinosaurs;[35] if this is true, its traits suggest that the first dinosaurs were small, bipedal predators.[36] The discovery of primitive, dinosaur-like ornithodirans such as Marasuchus and Lagerpeton in Argentinian Middle Triassic strata supports this view; analysis of recovered fossils suggests that these animals were indeed small, bipedal predators.

[Gawdzilla Sama]

Told ya.

[mistermack]

Told ya.

Yeh, well, you were there, so you should know.

[Gawdzilla Sama]

Told ya.

Yeh, well, you were there, so you should know.

Remember the Cambrian Explosion?

[GenesForLife]

Told ya.

Yeh, well, you were there, so you should know.

Remember the Cambrian Explosion?

Vaguely, yes.

Here is another paper that may be worth reading. This one examines some of the anatomical factors that can affect the method of locomotion and as a consequence place constraints and selective pressures on locomotory evolution.http://onlinelibrary.wiley.com/doi/10.1 ... 1/abstract

[Gawdzilla Sama]

You have a copy in English?

[GenesForLife]

You have a copy in English?