This is a question I’ve been addressing to palaeontologists, geneticists and various other ists for years.

A huge number of factors drive evolution, but essentially it’s a form of adaptation. The most important factors are alleged to be climate, environment and diet – which of course are far from mutually exclusive.

What I’ve never been able to understand, however, is how the physicality of the process happens: does it take place slowly over 750,000 years – or in a decade?

“It depends on the nature of the adaptation need and the species” said a not entirely helpful pointy-head to me five years ago. Yes, yes, yes – I know that. But what I mean is – and say we’re talking human beings here – how will the evolutionary change present itself? For example, how does the mother from the old species deal with the baby she’s just had from the new one? If the babe’s red and she’s green, she’s going to notice, right?

For example, I read a piece in Scientific American last year which blithely said that ‘over time, homo sapiens grew apart from homo erectus’. What do they mean by ‘time’ there – five years or five generations? And what does ‘grow apart’ mean – they chose different social circles, or hacked each other to death with the assbone of a jaw?

Now it may just be me, but I note that most scientists go noticeably woolly when you get down to the detail on this sort of issue. The really clever ones, however, respond well – because their interest is in the unsolved questions…not the defence of ‘settled science’. So it was that, about this time last year, one of this latter breed replied to my ‘How?’ question, “To be honest,we don’t really know because we’ve never seen it happen in a very high species”.

However, he did go on to assert (and I’ve Googled and yes, he’s right) that the two things most likely to speed up the process – or stop it dead, you can never tell in advance – are isolation, and how pressing the need is. This is why species on remote islands surrounded by thousands of miles of open water develop apart. Examples of this include the giant Komodo lizard, and New Zealanders.

What does anyone else think?

Editor’s note: I post these conundra because I genuinely don’t know the answers, and I’m interested in what others have learned. People who know all the answers and tell me this in a rude manner will have their comments taken down,and their little botties thrashed. (I think the plural of conundrum is conundrums by the way, but the OECD says otherwise, and who am I to argue with them?)