Dinosaurs survived 2 mass extinctions and 50 million years before taking over the world and dominating ecosystems

Sep 30, 2008
A herd of primitive carnivorous dinosaurs (Coelophysis, foreground) is enveloped by a sandstorm, while a large carnivorous crocodile-like archosaur (Postosuchus) and several early sauropodomorph dinosaurs lurk in the background. This reconstructed scene is taken from Steve Brusatte´s new book Dinosaurs which is advised by Mike Benton and will be published in October 2008 by Quercus Publishing, London.

Reporting in Biology Letters, Steve Brusatte, Professor Michael Benton, and colleagues at the University of Bristol show that dinosaurs did not proliferate immediately after they originated, but that their rise was a slow and complicated event, and driven by two mass extinctions.

"The sheer size of dinosaurs like Tyrannosaurus makes us think there was something special about these animals that preordained them for success right from the beginning," Brusatte said. "However, our research shows that the rise of dinosaurs was a prolonged and complicated process. It isn't clear from the data that they would go on to dominate the world until at least 30 million years after they originated."

Importantly, the new research also shows that dinosaurs evolved into all their classic lifestyles – big predators, long-necked herbivores, etc. – long before they became abundant or diversified into the many different species we know today.

Brusatte added: "It just wasn't a case of dinosaurs exploding onto the scene because of a special adaptation. Rather, they had to wait their turn and evolved in fits and starts before finally dominating their world."

Dinosaurs originated about 230 million years ago and survived the Late Triassic mass extinction (228 million years ago), when some 35 per cent of all living families died out. It was their predecessors dying out during this extinction that allowed herbivorous dinosaurs to expand into the niches they left behind.

The rapid expansion of carnivorous and armoured dinosaur groups did not happen until after the much bigger mass extinction some 200 million year ago, at the Triassic-Jurassic boundary. At least half of the species now known to have been living on Earth at that time became extinct, which profoundly affected life on land and in the oceans.

Historically the rise of the dinosaurs has been treated as a classic case in which a group evolves key features that allow it to rapidly expand, fill many niches, and out-compete other groups. But Professor Benton said the story isn't so simplistic: "We argue that the expansion of the dinosaurs took up to 50 million years and was not a simple process that can be explained with broad generalizations."

Source: University of Bristol

Explore further: Dwindling wind may tip predator-prey balance

add to favorites email to friend print save as pdf

Related Stories

How dinosaurs shrank, survived and evolved into birds

Aug 01, 2014

That starling at your birdfeeder? It is a dinosaur. The chicken on your dinner plate? Also a dinosaur. That mangy seagull scavenging for chips on the beach? Apart from being disgusting, yet again it is a ...

Symbiotic survival

Aug 01, 2014

One of the most diverse families in the ocean today—marine bivalve mollusks known as Lucinidae (or lucinids)—originated more than 400 million years ago in the Silurian period, with adaptations and life ...

One secret of ancient amber revealed

Jul 09, 2014

The warm beauty of amber was captivating and mysterious enough to inspire myths in ancient times, and even today, some of its secrets remain locked inside the fossilized tree resin. But for the first time, ...

Recommended for you

Dwindling wind may tip predator-prey balance

15 hours ago

Bent and tossed by the wind, a field of soybean plants presents a challenge for an Asian lady beetle on the hunt for aphids. But what if the air—and the soybeans—were still?

Environmental pollutants make worms susceptible to cold

20 hours ago

Some pollutants are more harmful in a cold climate than in a hot, because they affect the temperature sensitivity of certain organisms. Now researchers from Danish universities have demonstrated how this ...

Research helps steer mites from bees

22 hours ago

A Simon Fraser University chemistry professor has found a way to sway mites from their damaging effects on bees that care and feed the all-important queen bee.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Adam
not rated yet Oct 01, 2008
The Age of Dinosaurs was preceeded by the Age of Protomammals & Archosaurs - both of which lost many species in the terminal Permian and Triassic extinctions. Was never a sure thing, the rise to dominance, for any animal group - mammal, archosaur or dinosaur - and that should be a lesson to ourselves.