If I put you in a time machine and sent you back 450 million years ago,

you would step out into a world that is completely unrecognizable.

I could hardly expose you to more profound changes if I put you in a spaceship and sent you to another galaxy.

450 million years ago, virtually nothing you are familiar with today existed yet.

Perhaps needless to say none of us existed.

Neither did any of our ideas, governments, religions, rules, systems, institutions, money, none of these

existed yet. Borders between countries, they didn't exist. Countries didn't exist. Our continents

didn't exist, not just in conceptual ways, but in a physical way, the land masses that existed

were completely different to the ones you walk on today.

And the terms we use to define these things as something other than assemblages of atoms, these didn't exist either.

You would step out into a virtually lifeless land.

The most impressive terrestrial plants you would find would be grasses along the shoreline.

Land animals, at least in any significant way, they don't exist.

Trees won't exist for another hundred million years, and flowers won't exist for another 300 million

years.

You would feel completely alone until you jumped in the water, and then you'd probably wish you were alone.

Fish are just beginning to evolve, and the ones that exist haven't even evolved jaws yet. Mouths,

as you know them, don't exist. These animals are just swimming around with a ring of inward-facing teeth on their face.

And besides fish, animals you've never seen.

Creatures you could never hope to imagine dominate the ocean.

Complex messes of tentacles and shells, covered in bizarre and mysterious appendages, floating and crawling around the deep.

One of these animals is still around today, relatively unchanged by evolution.

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