No one will protect what they don't care about, and no one will care about what they have never experienced.

In the Baboon community, it is not how strong you are that is important, but who you know that counts

Human beings, because we're so clever, have removed every single one of those population limiting factors... So nothing controls our increase in numbers except our own wish. Since I first started making television programs, the population of the world has increased three times. That's an extraordinary notion. Can it increase four times? Can it increase five times? The Earth is a finite size. So a point will eventually come when we run out of food, when we run out of space and when we will have destroyed most of the natural world. So ought we to do something about it before that happens?

Very few species have survived unchanged. There's one called lingula, which is a little shellfish, a little brachiopod about the size of my fingernail, that has survived for 500 million years, but it's survived by being unobtrusive and doing nothing, and you can't accuse human beings of that.

It was regarded as a responsibility of the BBC to provide programs which have a broad spectrum of interest, and if there was a hole in that spectrum, then the BBC would fill it.

Do we really require so many gardening programmes, makeover programmes or celebrity chefs?

It seems to me that the natural world is the greatest source of excitement; the greatest source of visual beauty; the greatest source of intellectual interest. It is the greatest source of so much in life that makes life worth living.