For anyone interested in the origin of life I can heartily recommend Nick Lane's "The Vital Question", which sums up a lot of the most recent research in this area and also briefly talks about the Cambrian explosion. Really fascinating, deeply interesting stuff.
I'm reading Rare Earth: Why Complex Life is Uncommon in the Universe by Peter D. Ward and Donald Brownlee, which talks about the Cambrian explosion as well, in the context of the search for extraterrestrial life. It's perhaps a little dated, but a good read.
TL;DR: A "small, perhaps temporary, increase in oxygen" happened. Then "the advent of pervasive carnivory, made possible by oxygenation" managed to "set off an evolutionary arms race."
Because what would a science story be without adding in a little morality lesson, right?
sigh.
<rant>When did we start doing this? Did it begin with the talking animals from Disney? Carl Sagan and his desire to reach out to the masses? At some point we've so mingled drama and science that even a Nature science writer can't tell a science story without adding in a bit of either anthropomorphism or a morality play, or both.
You know, science isn't that dull on its own. It happens to be quite fascinating. Even without all the theatrics.</rant>
There are all sorts of lovely lessons and inspirations to be found in Science. I don't think there's anything wrong in that.
Disney? Ha! Ever read Aesop's fables? Native American Coyote stories? Moralizing is super ancient.
You do know that Science is the child of Alchemy, right? And that is nothing but gnostic moralizing, the pursuit of "gold" was actually the pursuit of a pure soul. By what means can we ensure our own place in heaven? How can we hack God with what's around us?
Part of the parcel of the human condition is pareidolia and nearly constant anthropomorphism. Personally I'm of the opinion that our swollen egos and reflex projection of our internal states on others and the outside world is the double edged sword by which we've staked our claim to our survival (and possibly our self destruction).
Yeah, I was kidding... the article doesn't imply any relevance to humans here. It just meant that once predators evolved to be ambulatory, prey either followed suit or became extinct.
That definition is at best imprecise and at worst inaccurate. The discussion page even shows someone objecting to that definition for the very same reason we are having this discussion.
The terms predator and prey are defined to describe predator-prey relationships, which are distinct (though similar) relationships to those of a cow eating grass or a bunny eating a carrot. Your definition of prey would include every single organism on Earth and necessitate a definition of predator that would include nearly all heterotrophs, excluding only some decomposers. Such definitions wouldn't be useful.
How would that set off an evolutionary arms race? Isn't evolution a passive phenomenon - initiated by random mutation effected by chance and one that should be unaffected by external circumstances like how many predators there are.
Mutation is a passive phenomenon. Evolution requires mutation and selection, and selection is very much subject to external circumstances. A mutation that makes an organism less likely to die from predation has no value in an environment without predators and won't be selected for. The same mutation in a sea of hungry enemies is a huge advantage and the organism that carries it will outcompete its relatives.
