I really liked the part of emergence that compared cities to brains. I’ve always wondered about this type of concept: what sorts of things can experience evolution? In an earlier part of Emergence, the author stated that anything that reproduces imperfectly and is faced with conditions that create a struggle for resources can evolve. So, one could then say that, for instance, our cells experience evolution. An individual cell needs energy, which it gets from the food broken down in our bodies, to survive. Also, our bodies only get a finite amount of energy at any given time, so one could imagine that some sort of competition exists between our cells to get a hold of this energy. After all, a cell that is better programmed to get at the food it needs is able to survive longer, and replicate (except in the case of brain cells, I think). So why don’t the cells in our stomach, which get the first dibs on food, selfishly take it all for themselves? It better ensures their survival, at least in the short run, to not share. So why do they share?
You can’t answer this question by examining it at the level of the cells themselves. You have to look at the larger structure: the human being. I have no idea how these cells got together and decided to form this larger structure, but once they did, it became in their favor, in the long-term this time, to not be selfish. If our cells all rebelled against the system and tried to hoard all of the food for themselves, we would die, which would mean they would die. So we have natural selection, and evolution, happening on two very different scales here. And it is obvious by the fact that we can walk and talk that the larger scale predominates. Why would the larger scale predominate, and what does this imply about even higher orders of evolution?
I imagine that higher orders of evolution predominate over longer time scales. Natural selection acts over the scale of generations. Generation times are much much shorter for cells than for humans. So, one could theoretically expect cell evolution to be important over shorter time spans, time spans we don’t care about. But over the time scales that matter to us, our evolution wins out. Now, what about higher time scales? Eventually, if the inhabitants of a city run rampant, without regard to a higher social order, the city will be destroyed, or at least, not worth living in. One could say that there is an evolution occurring amongst cities. They compete for resources, and those that compete best survive the longest. One could say that only those with “smart inhabitants” (analogous to “smart cells”—ones that aren’t completely selfish) will survive and prosper. One problem I see with this idea is the following: do cities really meet all the conditions for evolution that Dawkins described in The Selfish Gene? Specifically, in what way do cities evolve? It could just be that cities have an indefinitely long generation time, so the question is not “Who can best reproduce” but instead “Who can live the longest?” I don’t know. What do you think?
1 comment:
Comparing a mult-icellular organism to a city with individual cells as its inhabitants is an interesting analogy indeed. I've never heard of this book, Emergence, but just quickly glancing at it, it looks like a good read.
I'd like to attempt to answer your question. Higher levels of evolution may occur, but always in the context of lower levels of evolution. Clearly in the case of multicellular organisms higher social order is necessity, or else individual evolutionary benefits of individuals (similar to anarchy) destroys the organism as a whole. In this sense, organisms are a conglomeration of symbiotic communities consisting of cells. The point is that once you get to the multicellular level, favorable phenotypes that incur increased fitness are no longer judged only on individual, cell-by-cell basis, because natural selection acts on the entire organism. The reason you can say this is because the success of the organism, not the cell, determines how often its genes will be passed on. The whole point of living in a community is the idea that together we can achieve more, be safer, and be more succesful. However, this does not make Dawkin's "selfish gene"-evolution irrelevant. It provides the evolutionary fuel, if you will, for any evolution the organism experiences. Even though natural selection acts on the organism as a whole, the organism is still comprised of single cells. Evolutionary change can indeed accrue faster at the cellular level, and serves as the impetus for any change at the mult-icellular level, but it is constrained. The more complex an organism (especially once you start talking about highly intelligent organisms), the higher levels of evolution are possible, and the more likely that evolution on the simplest biological level (cells) are limited within the context of that particular "organism". Using humans as examples, a field I'm not particularly familiar with but find interesting, is the idea of cultural evolution. Humans, made of cells, effect their own evolution in ways that have nothing to do with evolutionary change at the cellular level- or does it? Again, often times impetus for cultural evolution has biological origins. The point is that varying levels of evolution are not mutually exclusive, but are in a mutual relationship with one another. As the level of evolution being examined increases, I think the more constrained evolution at the basic levels becomes. Basic-level evolution still serves as the foundational, true source of evolutionary change.
It would be interesting to see if different organisms in nature adopted different "governments", whether one prevails over another in certain environmental situations. Without over-simplifying the question, for example, do some multi-cellular organisms adopt a more communist-like governance, as opposed to others who are more on the side of democracy?
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