Dinosaurs are still with us, in the form of birds. But could the more canonical dinosaurs, like Tyrannosaurus, Triceratops and Stegosaurus, evolve again, if the climate and temperature switched back to what the conditions were like during the Cretaceous? Probably not.
While it’s a fun thought experiment, we really can’t predict what will evolve in the future. So much about evolution is down to contingency, luck and chance. Natural selection can’t plan ahead; it happens in the moment, to adapt organisms to immediate challenges.
As the late and great American palaeontologist Stephen Jay Gould mused: what would happen if we rewound the tape of life to some distant time and hit play? When it reached the present day, would the world be the same as it is now? He argued it would be different, perhaps much so.
Nothing is inevitable in evolution and little random quirks would set life off on unpredictable paths, different each time the tape was rewound and replayed.
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The more we study the fossil record, the more we realise that extinction is forever. Once a species or a group dies out, it just doesn’t come back. Take trilobites, for example. Climates today are broadly similar to those during times when they flourished in the oceans, yet trilobites haven’t returned.
So what about something similar to dinosaurs, could they evolve? It’s possible.
A powerful force in evolution is convergence: if different species face the same climate and environmental factors, they often evolve similar features to adapt to their surroundings. For instance, both dinosaurs (birds) and mammals (bats) independently evolved wings to fly.
If the Earth lurched into a Cretaceous-like climate, Tyrannosaurus and Triceratops would surely not re-evolve, but other large, lumbering, sublime reptiles might.
This article is an answer to the question (asked by Heather Warren, via email) 'If conditions on Earth changed, is it possible dinosaurs could evolve again? Would life… find a way?'
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