Life is cruel.
There were things eating other things.
There was predator-prey relationships going back potentially a billion years or more.
Nature is famously unforgiving.
The predators act as a culling agent and then the ones that remain are better able to deal with the predator.
That's what natural selection is about.
Predators relentlessly chasing down their prey.
There's all sorts of warfare that's going on in these ecosystems that we're not even aware of.
Life, as the philosopher Thomas Hobbes noted, is nasty, brutish and short.
It was probably a pretty hellish place to be at times.
I'm Alex Lathbridge and this is Crowd Science from the BBC World Service,
the show that answers your science questions about the infinite mystery of life on Earth and our place in it.
And in this episode, We've been wondering if life really has to be quite as brutal,
quite as violent as it is.
And that's because we received a question from Scott, who's been wondering the same thing.
He wants to know, was there ever a time when there were no carnivores and was it idyllic?
To try and find out, I'm going back to the very, very beginning.
Before there was life, there were rocks.
There would have been an ocean, we think, really early on,
and not a lot of land exposed above that ocean.