Natures Wonders (Introduction)

by dhw, Sunday, October 30, 2011, 18:02 (4773 days ago) @ George Jelliss

DAVID: What protects a woodpecker's brain from concussions?

http://www.bbc.co.uk/news/science-environment-15458633

I can't think of the itty-bitty Darwin steps to have the bird develop this solution. What made them decide to beat their heads against the hard bark of a tree instead of scooping up worms in the ground?

GEORGE: This is the argument from lack of imagination.

DAVID (quoted by George): "Only epigenetic mechanisms could do this, not Darwin's hunt and peck of chance mutation and natural selection."

GEORGE: Understanding of evolutionary processes has moved on since Darwin wrote 150 years ago, just as physics has moved on since Newton.

Thank you, David, for all these fascinating posts, but I’m with Darwin (and George) in the context of this example. I can well imagine Percy Pecker suddenly having the bright idea of tapping on wood, and being rewarded by a juicy grub. A few more taps and he gets a splitting headache, but the discovery has now been made. He’s found a new source of food (highly advantageous). With practice, the body gradually adjusts itself (epigenetics), and the message, technique and physical adjustments are passed on, so that gradually – or ittily-bittily over generations – perfected techniques and adjustments turn Percies into Woodies. Such minor adjustments over time can lead to new varieties and maybe to new species. The fact that Darwin did not know the actual mechanics of these heritable changes does not invalidate his theory.

That, of course, doesn’t explain major innovations such as sex, vision, flight, or sudden explosions of new species. However, David, I’d be interested to know exactly what you are advocating here. You also believe that evolution took place, and so how do you think Percy turned into Woody? Are you saying that God specifically designed Woody as a separate species, or preprogrammed him to knock on wood? If I were a theist, I would be inclined to believe that God created the initial mechanisms – including epigenetics – and then let the whole process run along precisely the lines that Darwin traced: a few forms giving rise to a vast range of self-generated variations and innovations all the way to us. George’s view is that the initial mechanisms made themselves. Neither view runs counter to Darwin.