exaptations (Introduction)

by dhw, Tuesday, July 16, 2013, 12:50 (4149 days ago) @ David Turell

DAVID: More common than adaptation:-http://www.the-scientist.com//?articles.view/articleNo/36508/title/Q---A--Evolution-Mak...-"If exaptations are pervasive, then natural selection—which few doubt is critical for the preservation and spreading of traits—may not be that important for the origin of innovations in life's history."-May I suggest that natural selection has no importance whatsoever for the origins of innovations in life's history. Darwin believed that innovations were caused by random mutations, whereas natural selection was the process which decided which innovations would survive and which would not. Not even Nature can select from organs that do not yet exist.
 
DAVID: If exaptations are that common, it is another major blow to Darwinian theory.-Not according to the article you have quoted!-The Scientist: Where did the notion of exaptations come from?
Andreas Wagner: Stephen Jay Gould first coined the term to describe traits that may be simple by-products of other traits. Also, Darwin said in his Origin of the Species back in 1859 that organs that serve a particular purpose may have originated for a completely different purpose. So even Darwin was aware that exaptations exist, although they didn't have that word at the time.-It's coming to something when Darwin's theory comes under fire because he didn't invent the word "exaptation" to cover a process he was aware of! According to AW "This opens a huge can of worms for evolutionary biologists because it becomes very hard to distinguish adaptation from exaptation." If it's so hard to distinguish, how can the researchers claim that exaptation is more common than adaptation? No doubt Darwin realized the same problem: you'd need a complete, consecutive fossil record of every organ to know what was adapted and what was new. And frankly, how much does it matter? The borderline between adaptation and innovation is bound to be blurred, and exaptation simply describes the grey area. -It stands to reason that if there is an intelligent mechanism at work within the genome (and there has to be, even though we can't account for it), and if an innovation survives because it is beneficial, its purpose could be changed if the environment demanded or allowed for change. The only other way the process could possibly work would be if you believed in a god who intervened in order to create every single innovation and adaptation! A totally unnecessary complication even for a theist.
 
DAVID: Another example of pre-planning?-No, another example of the intelligent genome at work.