Monday, 20 August 2012
Watch the birdy!
Charles Darwin wasn't an expert on birds, and we can forgive him that. He collected a huge pile of birds on the Galapagos, but didn't pay them much attention at the time. On his return home, they were passed to an ornithologist friend for identification. The ones that have passed into the scientific history books - later known as Darwin's Finches - aren't actually proper finches, but a group of twelve or more species of fairly dull-looking birds that turned out to be very important in demonstrating some of Darwin's ideas.
What he noticed about these finches is that while at first glance they were fairly similar, their beaks were adapted to suit their individual lifestyles and diets - adaptive radiation - and the species varied from island to island. Darwin noted "one might really fancy that one species had been taken and modified for different ends." This idea was expanded on in 'Origin'.
A few years ago, a study of one of the group - the excitingly named medium ground finch - showed their beaks had changed noticeably over two decades, as individuals with shorter beaks were better able to cope with competition with the recently arrived large ground finch. Shortbeaks fed better and bred more successfully, meaning... well, you get the idea. Recently, the genome of of Medium (for short) has been determined, and and further adaptation will be carefully tracked at genetic level.