Study: Dinosaurs "Shrank" Regularly To Become Birds

An anonymous reader writes A new study suggests that large dinosaurs shrunk to small birds to survive over a period of around 50 million years. Aside from a few large species, most modern birds are predominantly tiny and look nothing at all like their prehistoric meat-eating ancestors. The evolutionary process that governed this transformation has not been well understood, but now researchers from the University of Adelaide in Australia have put together a detailed family tree mapping the evolution of therapod dinosaurs to the agile flying birds we see today. Their results indicated that meat-eating dinosaurs underwent several distinct periods of miniaturization over the last 50 million years which took them down from an average weight of 163kg to just 0.8kg before finally becoming modern birds.

Comments

Smile

[nospam007]

Think of it as evolution in action.

Re:Smile

[Confusador]

You're not feeding a religious troll, you're feeding a racist troll.

Re:Smile

[StripedCow]

Actually, because of the expansion of space-time, the dinosaurs stayed the same size.

Makes Perfect Sense

[rmdingler]

In times of extraordinary resources, an ecosystem's offspring are afforded the opportunity to grow larger, and larger is often a breeding advantage.

In times of constriction of resources, those life forms with the minimal caloric needs tend to flourish.

What a beautiful and strange World it must have been in the dinosaurs heyday to support a seven ton carnivore and a 50,000 to 100,000 kilo plant eater.

Re:Makes Perfect Sense

[Arker]

"There was a lot more oxygen in the air back then. It wasn't just hotter. With the lower oxygen levels the huge dinos wouldn't do so well because they didn't have muscles for breathing like we do."

I think you are rather badly mistaken. There was actually much less oxygen in the atmosphere then.

Warning, link is not really a webpage, js required :( but you can search yourself for a better source.

Re:Makes Perfect Sense

[Artifakt]

There's also the argument that wings evolved from smaller structures which were held angled down to in turn hold the running bipod proto-bird (or advanced dinosaur) down when making sharp turns at high speeds (like automotive spoilers) . Strange as that idea sounds, if this actually worked, then it helps explain what's otherwise a pretty large gap - evolving flight. Arms races, as this one where the predators would be trying to outcorner their fleeing prey, and the prey would be trying to evade ever more agile predators, are often considered as explanations for complex evolutionary paths, and may well be true in this case, but it also means we would have an even harder time matching feathers to any specific climate data - as we don't know whether insualtion was the major advantage of the structures just because the animal didn't have the wing surface for actual flight..

Penguins Came from Whence?

[flyneye]

I wanna see the armor plated Tyrannopenguin.

The Red Queen

[NoNonAlphaCharsHere]

I'm sorry, birds are the showiest class on the planet. Any theory about how they went from ~160Kg to ~1Kg in (only) 50 million years needs to have a healthy dose of sexual arms race to be plausible.

Dinosaurs went obsolete

[Anonymous Coward]

Because of the square cube law, gigantism is energetically expensive. The bigger an animal gets, the heavier it gets (disproportionately), and the more energy it needs to move. But size is relatively easy to tweak genetically, so making animals bigger to out compete their mating or territorial/predatory rivals must have been a solution which evolution hit on pretty quickly. But then evolution moved on, developing more sophisticated technology like feathers, hollow bones, and more powerful brains which could support flight and cooperative pack hunting, and gigantism became a relatively more expensive and less useful trait. Huge dinosaurs disappeared, for the same reason huge battleships did. Put a t-Rex into a forest with a pride of hungry lions. How long do you think the Rex would last?

- Tristan

Re:Dinosaurs went obsolete

[ArcadeMan]

Put a t-Rex into a forest with a pride of hungry lions. How long do you think the Rex would last?

What do you mean? An African or European tyrannosaurus rex?

Re:Dinosaurs went obsolete

[gwolf]

Do you mean Laurassian or Gondwanan tyrannosaurus rex?

Bad phrasing

[twistedcubic]

This is evolution. The dinosaurs did not "shrink". The smaller dinosaurs within a species had a higher survival rate.

Re:No no no.

[ArcadeMan]

Wrong. The noodley appendage is a make-believe idea put in our heads by the Invisible Pink Unicorn to test our faith in her.

Re:No no no.

[mark-t]

Please.

Pastafarianism is readily historically verifiable as being deliberately conceived of as a fake religion for the express purpose of satirizing other religious beliefs, not so much to mock those specific beliefs, but to actually show how ludicrous it is to use science classes in school to teach scientifically unverifiable stories about the origin of mankind, arguing that the Flying Spaghetti Monster story has exactly as much scientifically credible as any other unverifiable account of the origin of mankind (which is a mostly accurate assessment, the only difference that I can think of being that how the story of the FSM came about, and the entire purpose of its existence, to mock the teaching of Intelligent Design in schools, is very well historically documented, so the comparison isn't valid 100%... but it's close).

So if you are going to lay claim to any kind of sincere belief in a religion, you should probably try picking one whose origins are lost in obscurity by the passage of time, or at least pick one where there isn't an abundance of documentation to show that the originator only invented it to mock a specific idea, not as something that anyone should necessarily seriously believe in.

Re:No no no.

[Boronx]

Please. That origin story was put there by Satan to test our faith. You don't really believe it was all made up, do you?