The whole of science, and one is tempted to think the whole of the life of any thinking man, is trying to come to terms with the relationship between yourself and the natural world. Why are you here, and how do you fit in, and what's it all about.

It's coming home to roost over the next 50 years or so. It's not just climate change; it's sheer space, places to grow food for this enormous horde. Either we limit our population growth or the natural world will do it for us, and the natural world is doing it for us right now.

They always mean beautiful things like hummingbirds. I always reply by saying that I think of a little child in east Africa with a worm burrowing through his eyeball. The worm cannot live in any other way, except by burrowing through eyeballs. I find that hard to reconcile with the notion of a divine and benevolent creator.

Bringing nature into the classroom can kindle a fascination and passion for the diversity of life on earth and can motivate a sense of responsibility to safeguard it.

If I were beginning my career today, I don't think I would take the same direction. Television is at a crossroads at the moment. And although I am not up to date technologically, I suspect that somewhere out there people are conveying things about natural history by means other than television, and I think if I were beginning today, I'd be there.

Can a growing human population still leave space for wildlife?

I'm against this huge globalisation on the basis of economic advantage.