From the BBC:
Theropods shrunk 12 times from 163kg (25st 9lb) to 0.8kg (1.8lb), before becoming modern birds.
The researchers found theropods were the only dinosaurs to get continuously smaller.
Their skeletons also changed four times faster than other dinosaurs, helping them to survive.
It sounds like a program. Tell us more.
From New Scientist:
“No other dinosaur group has undergone such a long and extended period of miniaturisation,” says Mike Lee of the South Australian Museum in Adelaide. “Statistically this trend was far stronger than by chance, analogous to flipping a coin a dozen times and getting all heads.”
Lee and his colleagues have performed the most comprehensive analysis yet of fossil theropods, the two-footed meat-eating dinosaurs, like Velociraptor, from which birds evolved. They have charted how 224-million-year-old dinosaurs weighing 238 kilograms evolved into proto-birds, including Archaeopteryx, that weighed just 0.8 kg.
So not a fluke. Plus:
Their small size may also have helped birds survive the mass extinction that wiped out all the other dinosaurs 65 million years ago, says Bhullar. “We have mounting evidence that the end-Cretaceous extinction simply took out all landlocked animals above a certain size, say a few kilograms,” he says. “Birds happened to be among those dinosaurs that were small, and were lucky to boot.”
The study concluded that the branch of dinosaurs leading to birds was more evolutionary innovative than other dinosaur lineages. “Birds out-shrank and out-evolved their dinosaurian ancestors, surviving where their larger, less evolvable relatives could not,” says Associate Professor Lee.
How can a group be more evolutionarily innovative if evolution is a fluke?
Something is not adding up, and it isn’t Excel.
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6 Replies to “We are told: Dinosaurs regularly “shrank” to become birds”
Then they shrank even more and became light as a feather.
I was watching a humming bird outside the window yesterday. Excuse me for being somewhat skeptical about the conclusions they draw from their analysis.
Now let’s line up a few dozen cranes, bulldozers and hammers on the left and a few dozen nails on the right and add a story to fill in the gaps and this will show how cranes evolved into nails.
Oh, by the way, did those dino-bird researchers ever get around to demonstrating what dinosaurs evolved from? It seems that all the dinosaur fossils appear as clearly identifiable dinosaurs, not part-dinos evolving from something else.
According to Wiki: dino’s evolved from so-called archosaurs. And, again according to Wiki, “living representatives [of archosaurs] consist of birds and crocodilians.”
I take it that this answers your question and can be marked solved and locked.
Thank you Box. Yes, I should have checked Wikipedia. In fact, I was going to write something like that on Wikipedia myself, but cab-drivers and wine bottle collectors have said it so much better.
My understanding is that small dinosaurs were always present and that feathered dinosaurs co-existed with T Rex. So it makes as much sense to say that “theropods that had evolved into giant monsters because that increased their chances of survival suddenly discovered that bigger was badder, and died out. Only the smallest of the theropods survived long enough to get killed by the comet that hit Yucatan”.