8 October 2010
Scientists have found dinosaur-like footprints in a 250-million-year-old rock, suggesting that first dinosaur-like creatures emerged up to nine million years earlier than previously thought.
Click to hear the report:
These earliest dinosaur-like animals were about the size of domestic cats. They would have weighed two or three pounds (1 to 1.5 kilos) and walked on four legs.
But what's really intrigued scientists is that they date from two million years after the worst mass extinction event in the history of the planet.
It was a time when volcanic eruptions, sudden global warming and a stagnation of the oceans wiped out more than 90% of all life on Earth.
Up until recently scientists thought that dinosaurs emerged 15 to 20 million years after this event. But the new footprints suggest that they arose directly as a result of the devastation, filling a gaping ecological void. Without the mass extinctions there would have been no dinosaurs.
Pallab Ghosh, BBC News, London
Click to hear the vocabulary:
large reptile that lived around 200 million years ago
- mass extinction
large number of deaths in a relatively short period of time
- volcanic eruptions
explosions of ash, fire and liquid rock coming out of the earth
- global warming
increased average temperatures across the world
- wiped out
connected with plants, animals and the environment
area of empty space