Kalimero writes:
I can recognise the charactaristics (critiria you may say) of evolution
I'm still having troupble seeing these.
I can see some parallels, but there are still some important differences that, to me, are enough to negate the usefulness of the concept of 'evolution driven by natural selection' as an analogy for brain development.
Kalimero writes:
1. reproduction - neurons grow throuout life, although less in older age, there are always enough neurons to go through selection.
Growth is not reproduction. They can sometimes regenerate after injury, but neurons in the CNS cannot replicate themselves or give birth to progeny.
Kalimero writes:
modification - not much to say, neurons are different from each other.
That's variation in your 'population'. One criteria for evolution, yes, but 'descent with modification' is now broadly interpreted to mean heritable mutation. And there can be no heritability without reproduction.
Kalimero writes:
selection - I thimk that the genetic evolution of the brain was "pushed" to form a brain with the capability to 'freely' respond to "pressures" from the outside world (that are relevent to the senses - obviously). I think thats why people tend to describe the brain as flexible.
If you want to postulate a selective force, I think we will need to define it more precisely than that. As I understand it, the 'selective force' supposedly at work here is 'usage' - synapses that fire frequently make for neural pathways that are more likely to fire again in the future. Once agian, I have a problem with a 'synapse' as a unit of selection, though.
Kalimero writes:
heredity
I am still not clear on what kind of mechanism in the brain could possibly be analogous to heredity, simply because I have yet to find any form of neuronal reproduction that would seemingly be a prerequisite for heredity.
This message has been edited by EZscience, 04-21-2006 07:53 AM