Discussion of everything related to the Theory of Evolution.
I will not quote, because my Ctrl key is broken
I jump from humans to ecosystems because I generally find examples very helpful in my thinking/discussions. When I generalize, I use the word 'system' and my argument is indeed that in general, complex systems have greater potentiality, which helps them cope with change better, rendering them more robust in the long run. Of course the environment may permit or even force complexity reduction under certain conditions but, in general, variety and multiplicity (as good a definition as any) are favored.
Not only am I not ignoring society and culture, it's exactly what I'm ultimately interested in. The argument is very important to me, for philosophical reasons. Humans like to oversimplify things and we like to put everything in neat little boxes, expecting everything and everyone to fit in them. If the argument holds, one can not argue against the imperative need for a culturaly rich world, where differences are not only accepted, but encouraged to blossom. The tendency of most developing countries to mimic the western way of life is but an example of how much the importance of differentiation is being ignored. Another example is our tendency for centralized government with very predictable structures, as opposed to smaller, more loosely organized units (there was an excellent discussion of this in a book on chaos I read a couple of years ago).
This is getting a bit more philosophical, but what do you mean "inevitable"? The only things that don't appear to be deterministic are quantum processes. Does quantum indeterminacy allow for mutations to be truly random i.e. indeterminate? I imagine that it could since electromagnetic radiation, which can induce mutations at high wavelengths, is a wave . But I don't know if we're certain of indeterminacy, or if indeterminacy is merely what is suggested by the apparent randomness of small particles like electrons (and photons ).
But back to biology. Have you considered that the human niche is actually a collection of niches? Most organisms cannot change their niche significantly without centuries evolution, but we appear to transcend that with our intellectual responsiveness. More to the point, I speculate that the evolution of such responsiveness could be driven by an inability to establish reproductive barriers between popoulations.
Normally, if different populations are exposed to different environments, the differing selection pressures push the population genetics in different directions, and gene flow between the populations interferes with this necessary divergence. An examples is the great tits on Vlieland in the Netherlands. One Vlieland population recieves more gene flow from the mainland than the other, and individuals of that population are less adapted to the Vlieland environment as a result. This is the sort of situation where one sex will begin avoiding immigrants to avoid their bad genes.
Hypothetically, this problem could be circumvented if you have genes that manifest differently in different environments. Thus such responsiveness to the environment could be an alternative to speciation. Furthermore, if there are some situations where reproductive barriers cannot be established, those situations may even drive the evolution of such responsiveness as a necessary alternative.
Even in deterministic chaotic systems, the smallest perturbation can lead to drastically different situations, so the inevitability of a particular outcome has little to do with determinism. The real question is, is the universe structured in such a way as to permit the countless number of incremental experiments required for intelligence to evolve? Determinism or not, it comes down to probabilities.
The second part of your post essentially says that there may be a high probability for the emergence of traits that trascend the requirements of specific niches. I agree, but I don't see how the reproductive barriers have anything to do with it. I think I heard somewhere that homo sapiens may have come from a very small group of humanoids who had to cope with a sudden change in climate, which essentially turned their environment into desert, very fast. Given the very little time they had to adapt, it seems likely that selective pressure for high intelligence would be quite strong. The other humanoids were probably doing just fine in their large niches and had no need for even bigger brains. The gene flow we are aware of, is between homo sapiens and Neaderthals, right? But intelligence had already evolved by that time. Could you help me understand your point better?
I don't know. I haven't learned about Homo evolution yet.
The idea is only speculative, but it seems reasonable to me. I don't know our genus history, so the following is only hypothetical.
Suppose we have a single population of primitive Homo being exposed to drastically different environments in different areas. One area is a grassland full of predators, while the other is a forest of fruiting trees. The grassland is pushing for bulkier Homo that can fight off predators with their bare hands. The forest is pushing for small and lightweight Homo that can swing on the branches to collect the fruit. That is, the population is undergoing disruptive selection. However, some Homo are starting to make tools. In the grassland, these Homo make blunt weapons. In the forest, these Homo make long-reaching sticks with knifed tips that sever the fruits fromt he branches.
If this population can establish reproductive barriers across the two environments, then the grassland and forest will strongly favor bulkiness and lightweightedness, respectively. Females in each subpopulation may begin to select for the traits that are advantageous in their environment. The tool-making traits may be eliminated simply by genetic drift. Or the tool-making traits may have certain disadvantages, such as higher energy requirements, that simply aren't worth it.
In contrast, if this population cannot establish reproductive barriers, then neither bulkiness nor lightweightedness will be strongly favored since neither solves the problem of surviving in either environment. Tool-making might be the more favored course of evolution because it solves that problem.
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