When you drive to the grocery store, your intention is not to change the world, it just happens to have that impact. So we've done a lot of things without even realizing it, and yes, just being unusual, as you say, does not put you above, in a sense, any of the other organisms with whom we share this planet.

Of the many species that have existed on earth - estimates run as high as fifty billion - more than ninety-nine per cent have disappeared. In the light of this, it is sometimes joked that all of life today amounts to little more than a rounding error.

Mitochondrial DNA, which is a sort of abridged version of DNA, is passed directly from mother to child, so it's something that can be looked at to trace matrilineal descent.

There's this idea of shifting baselines. It was coined by a guy named Jeremy Jackson. It's the idea that every generation takes what it sees, and says, "Okay, well, that's the norm."

As soon as you acknowledge that we're changing the planet on this scale, that it has very potentially massive repercussions and very damaging repercussions, then the next question is okay, what are we going to do about it?

There are a lot of things that we could do to minimize what we're doing, but we're not getting back those frogs that I saw that no longer exist.

When you drive to the grocery store, your intention is not to change the world, it just happens to have that impact. So we've done a lot of things without even realizing it, and yes, just being unusual, as you say, does not put you above, in a sense, any of the other organisms with whom we share this planet.