Musings and photos of wild and everyday life

Darwin & those Finches

Sunset over Galapagos Is In 1835 – no don’t worry I’m not a history fan – Darwin arrived in the Galagagos Island group on board the HMS Beagle, and proceded to cause both controversy and scientific breakthrough.

The controversy was not about collecting samples of incredible species that continue to be in great danger, but rather about the belief that the knowledge he was bringing was somehow denying God. Go figure!

Anyway the breakthrough was seeing that species had evolved to best exploit their environment and the niche they found themselves in, by ‘natural selection’.  This theory essentially held that tiny differences within individuals of a species tended to be  bred on in a magnifying way if the peculiarity was useful – i.e. helped in finding food, mating or surviving and that conversely, peculiarities that made the individual less attractive or strong etc. tended to die out due to the ‘survival of the fittest’ primciple.Large Ground Finch eating Punta Suarez  Espanola Galapagos
This theory has revolutionised the scientific view and led to many more studies so that it is taken as gospel (sorry) today.

Darwin collected many samples including a number of finches from different islands and it is these finches that are generally considered to be at the root of his theory.

Small Ground Finch F Rabida Is GalapagosDifferent  islands, for example, contained very similar finches but with slight differences that could be accounted for by the topology, type of cover or available food. Where seeds were small, beaks were small and where seeds were large or tough, beaks were large.

Green Warbler Finch highlands Santa Cruz Is
Because the islands were separate, moving apart and hadn’t been interfered with by us, there would have been little interbreeding between different islands and the differences must have been down to selective breeding.

Medium Ground Finch M on beach Gardner Bay EspanolaThere were finches for most ‘purposes’ – Green Warbler Finches with narrow beaks for picking insects; Medium Finches for medium seeds and even Cactus Finches, specialised in boring into Cactus flesh.Common Cactus Finch F feeding on Prickly Pear Cactus Santa Cruz Is

Unaccustomed as my eyes were to identifying these finches  I may have erred in naming.  It seems similar to identifying our warblers!

San Cristobal Mockingbird Cero Brujo San Cristobal Galapagos

San Cristobal Mockingbird Mimus melanotis Cero Brujo San Cristobal

Galapagos Mockingbird Santa Cruz Is

Galapagos Mockingbird Mimus parvulus on Santa Cruz Is

Although more celebrated, it was not the Finches that gave Darwin his first insight into this selection process but rather the Mockingbirds that he had also collected.

Floreana Mockingbird Floreana Is Galapagos

Floreana Mockingbird Mimus trifasciatus on Floreana Is Galapagos

Espanola Mockingbird on beach Gardner Bay Espanola

Espanola Mockingbird Mimus macdonaldi on beach Gardner Bay Espanola

Apparently, unlike with the Finches,  he kept note of the island from where he had collected the Mockingbird samples.  This led him to notice distinct differences in characteristics of birds from different islands.  The first Mockingbirds encountered on Chatham Is. (now San Cristobal) seemed similar to those collected previously in South America.  Birds collected on a number of different islands, proved to have different markings on their cheeks and chest and different sized bills.

Hopefully these great creatures that survived Darwin and many other collectors can now survive the tourist boom.

Advertisements

One response

  1. Jimmy

    Didn’t know the finches caused it all!

    August 20, 2012 at 9:54 am

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s