The most extraordinary thing about trying to piece together the missing links in the evolutionary story is that when you do find a missing link and put it in the story, you suddenly need all these other missing links to connect to the new discovery. The gaps and questions actually increase - it's extraordinary.

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 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.

I'm swanning round the world looking at the most fabulously interesting things. Such good fortune.

Nothing in the natural world makes sense - except when seen in the light of evolution

Birds were flying from continent to continent long before we were. They reached the coldest place on Earth, Antarctica, long before we did. They can survive in the hottest of deserts. Some can remain on the wing for years at a time. They can girdle the globe. Now, we have taken over the earth and the sea and the sky, but with skill and care and knowledge, we can ensure that there is still a place on Earth for birds in all their beauty and variety - if we want to... And surely, we should.

Opponents say natural selection is not a theory supported by observation or experiment; that it is not based on fact; and that it cannot be proved. Well, no, you cannot prove the theory to people who won't believe in it any more than you can prove that the Battle of Hastings took place in 1066. However, we know the battle happened then, just as we know the course of evolution on earth unambiguously shows that Darwin was right.