Deep Within Us

From Carl Zimmer over at The Loom comes this pointer to an essay about Tiktaalik and its significance by Neil Shubin, one of Tiktaalik's finders.

From the introduction by John Brockman:

When we look back after 370 million years of evolution, the invasion of land by fish appears special. However, if we could transport ourselves by time machine to this early period, it isn't clear whether we would notice anything extraordinary. We would see a lot of fish, some of them big and some of them small, all of them struggling to survive and reproduce. Only now, 370 million years later, do we see that one of those fish sat at the base of a huge branch of the tree of life—a branch that includes everything from salamanders to humans. It would have taken an uncanny sixth sense for us to have predicted this outcome when our time machine deposited us in the middle of the Devonian.

Shubin says:

"We live in an age of discovery where the classic stories of evolution have become the focus of vigorous new approaches from genetics and developmental biology. Breakthroughs in genetics are beginning to tell us how bodies are built, in essence giving insights into the recipe that builds animals from a single celled egg. Couple these breakthroughs with the remarkable fossil discoveries of the past decade, and we have opportunity to present a new worldview of the human body.

One of the most important things Shubin says is this:

We now know that the "great" transformation from water to land has so many fossil intermediates that we can no longer conveniently distinguish between fish and tetrapod, that living fish are bridging the water-to-land transition today, that some of the genes implicated in the ancient transition still reside and mutate in living animals, making everything from fish fins to human hands.

Check it out: it's a lovely piece of writing, especially in its final, summary paragraphs.