Evolution in Action

Last week some colleagues and I were chatting about 1976. I can't actually remember it being, as I was, just a wee bairn (that's "baby" for all you Aussies and southerners) at the time but ten years later I suffered a bout of eczema and was told by my doctor and my mam that I'd also suffered it in 1976 and interestingly both years were extremely hot (as hot as it gets in Newcastle anyway). This then led my mother to reminisce about the hose-pipe ban (yes, we get them in England too) which led me to conclude that the summer of 1976 must have been hot and dry.

Meanwhile, my Australian colleagues were recollecting an entirely different situation in which 1976 was extremely wet, the wettest year any of them could remember. The contrast was interesting.

The following day I read in The Weather Makers (The history and future impact of climate change) by Tim Flannery, a well known and controversial Australian scientist, that 1976 was a particularly harsh El Nino year and that it was a pivotal year in the history of recent climate change. The following year brought drought to many areas, including the Galapagos Islands. Here scientists witnessed something quite astonishing. As they watched in despair the majority of the region's 1300 native finches, famously used by Darwin as an example of evolution, died leaving a population of only 180. These birds survived because they had the largest beaks and were able to crack open tougher nuts. Of the survivors, only 30 were female. Imagine the kerfuffle when the rains returned and the mating season began. 150 males trying to mate with 30 females. That's a ratio of 5 to 1. It's not going to work really, is it? Not surprisingly, the majority of the males didn't get a look in and those that were successful in mating with the females were, once again, those with the largest beaks, enabling them to viciously fight for the honour of reproducing.

These two events resulted in a measurable increase in the average size of the Galapagos finch's beak! Thanks to Darwin's research biologists were able to compare the new average with 200 years worth of beak measurements and concluded that they may have witnessed the evolution of a new species.

I find it amazing that evolution can happen over such a short period of time. It's beautiful, yet also a little scary. If that's what one hot summer can do to a species, what does the future of climate change hold for the rest of us?

The Weather Makers is a fascinating read and I'm bound to end up blogging a few more interesting snippets of info from it so watch out. (I'll try not to get on my soap box though. I seek merely to inform!).

Interestingly, whilst looking for links for this blog I came across an article on BBC news warning that the recent UK winter drought could have "serious consequences" and that south-east England is the driest since 1976 (Concerns over UK winter drought). Hope you get some rain soon.