exaptations (Introduction)

by David Turell , Tuesday, July 16, 2013, 16:15 (4149 days ago) @ dhw


> DAVID: If exaptations are that common, it is another major blow to Darwinian theory.
> 
> dhw: Not according to the article you have quoted!
> "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." 
> 
> dhw: 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.-Not an unnecessary complication. Lets use Tattersall's favorite exaptation, the adaptations for speech. The lowering of the larynx requiring the development of the epiglottis as a trap door to prevent choking, reshaping of the pharynx, and development of special tongue muscles and attachments all began 500,000 years BEFORE Homo erectus. H. Erectus probably had some rudimentary speech. Why did evolution create a disadventageous larynx, when no need existed at the time. An 'intelligent genome' with foresight? That would be a stretch even for you.