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.

In a poll commissioned by Time and CNN, two-thirds of American parents said they think that their children are spoiled.

The Earth is big. There are huge natural forces that have worked over geological time. But it turns out, when you look carefully at the geological time, you can't find anything like us.

Well in the scientific there is virtually no debate over certain things. For example, that we are changing the world. Humans are changing the world very radically, very dramatically. Climate change, which I assume is one of the points you're alluding to, is at the heart of this.

If in your lifetime you watch a species go extinct, or plummet almost to the point of extinction, that is a sign that something really serious is going on.

Neanderthals were pretty smart, and if we actively killed them off, then probably we did so in the same way that humans kill each other.

I did not mean to suggest that autism could be traced to Neanderthal genes. The point is that some genes that have been implicated in autism changed pretty significantly between the time Neanderthal line and human line split.