There are some images that you carry with you from your childhood – images that touched your mind with wonder or with the glimmerings of new thought. For me, one such image was a rather crude artist’s impression of animals leaving the sea to walk on land. The sketch may have been crude, but the idea of evolution was stupendous – something to mull over for days! Of course, I had no idea then that years later, that image would come to life as a fossil.
In 2004, Tiktaalik roseae, a crocodile-like fossil, was found on Ellesmere Island, Canada. According to the Guardian, it showed how creatures first walked out of the water and on to dry land more than 375m years ago. http://www.guardian.co.uk/science/2006/dec/22/2006inreview.taxonomy
By the way, this creature has a home on the Net now http://tiktaalik.uchicago.edu/
To me, the Tiktaalik seems to signify the idea of evolution itself, the idea that life (call it the Selfish Gene, if you like) will constantly push organisms to change, to move outside their zone of comfort, and to procreate, sometimes at tremendous sacrifice.