Memory, Adaptation and Entropy
Posted by Nicole Tedesco on July 26, 2011
I will write more in the coming weeks and months about the various types of memory a life form may leverage in order to adapt to its environment. An interesting article from ScienceDaily illustrates how epigenetics, those chemical changes which alter the way DNA is processed (or not processed) in our cells, provide an organism with an adaptation subsystem that helps it better fit its environment,
Adaptation cannot occur without memory. Organisms, including plants, leverage many forms of memory. Other than chemical and physical construction, perhaps the most important characteristic which differentiates kinds of memories is the informational entropy capacities of those memories. Memory systems with higher entropy capacities can assimilate larger informational variety. As the informational variety (entropy) capacity of a memory system increases, so will rise the organisms potential to adapt to a greater number of environmental conditions. That is, the higher the entropy capacity, the higher the potential utility of the adaptive system.
From the article,
Epigenetic memory comes in various guises, but one important form involves histones — the proteins around which DNA is wrapped. Particular chemical modifications can be attached to histones and these modifications can then affect the expression of nearby genes, turning them on or off. These modifications can be inherited by daughter cells, when the cells divide, and if they occur in the cells that form gametes (e.g. sperm in mammals or pollen in plants) then they can also pass on to offspring.
I will also illustrate in the coming weeks and months that adaptive system utility is not merely a function of higher information entropy capacity. Adaptive system utility can also be extended by the system’s ability to “clean house”, “collect the garbage” and reduce information variety when the system has become saturated.