I ordered a coffee and a little something to eat and savored the warmth and dryness. Somewhere in the background Nat King Cole sang a perky tune. I watched the rain beat down on the road outside and told myself that one day this would be twenty years ago.

I became quietly seized with that nostalgia that overcomes you when you have reached the middle of your life and your father has recently died and it dawns on you that when he went he took some of you with him.

We are so used to the notion of our own inevitability as life's dominant species that it is hard to grasp that we are here only because of timely extraterrestrial bangs and other random flukes. The one thing we have in common with all other living things is that for nearly four billions years our ancestors have managed to slip through a series of closing doors every time we needed them to.

I still enjoy traveling a lot. I mean, it amazes me that I still get excited in hotel rooms just to see what kind of shampoo they've left me.

It's hard not to be kind of pessimistic about human beings generally, because we do tend to mess things up. If you just look at the history of extinctions, we've killed off an awful lot of animals - and I don't think we're doing a very good job of looking after the planet.

No one knows, incidentally, why Australia's spiders are so extravagantly toxic; capturing small insects and injecting them with enough poison to drop a horse would appear to be the most literal case of overkill. Still, it does mean that everyone gives them lots of space.

Consider the Lichen. Lichens are just about the hardiest visible organisms on Earth, but the least ambitious.