Sunday, August 16, 2009

Discussion Thread: The Future of Human Evolution

I was thinking I'd be able to type a bit more on the topic, but I ended up thinking of what I think is a succinct way of putting it: I doubt humans will develop big veiny brains like in bad science fiction because we've formed what I believe is called a negative feedback loop: As our brains grew in the past, we developed technology to act as substitute brain matter. We're at the point where we have books, the internet, experts on reference, and so forth to outsource the need for brain space. With these non-genetic substitutes, there's a lot less selective pressure to confer significant advantage to those who might develop mutations that result in more powerful brains.

Being able to remember or figure out something without a search engine doesn't make you that much more likely to get laid.

4 comments:

Dark Jaguar said...

I think there's a much simpler truth here. Whatever brains conferred in terms of an advantage, and surely there's a lot, the fact is that today, in first world nations at least, the big threats don't come from nature (with some exceptions). Further, the big pressure has always been preservation of the genes, not the individual. I personally think our biggest selective pressure is just basic sexual selection. This isn't to say I think brains will slowly shrink in size either. The selective pressure there is simple resources. We have all too much food for anything to go vestigial I'd think.

I have to wonder if there's really any evolutionary pressure on humans at all in first world countries, aside from outliers that medical science can't currently help. At best we could say that those who reproduce more are selected for. I'm sure actual biologists could provide something a lot more well researched, but that's basically my impression of the current "state of play".

However, on another note, I think that humans may be capable of completely changing the terms of evolution. You mentioned "outsourced brain power", but I prefer to think of it as "expanded", the whole extended phenotype thing. Certainly I don't feel I've been thinking less, and in fact access to things like Wikipedia have set my mind ablaze on all sorts of topics.

On an evolutionary time scale, I seriously doubt there will be a future where our technology is the same as now and natural selection had time to actually work on us without our interference. I think we'll very likely in the next few centuries more or less take over our own DNA and body design and natural selection will play a very small part. If anything, it'd be used in simulation testing in evolutionary algorythms to get new ideas for developing. Now, maybe I'm too optimistic, but I think it's either this, or humanity just goes extinct. I don't think there's really a middle ground where humans would just outlaw all genetic alteration and millions of years from now humans have just evolved via natural selection while simultaneously maintaining the same sort of civilization we have now.

Bronze Dog said...

I don't think humanity's going to exactly remain the same, but with reduced selective pressures, genetic diversity may climb for both positive and negative traits. If we get technology to render more and more problem genes moot, they'd essentially be neutral traits, subject to genetic drift, rather than natural selection. Some of those traits might reach fixation in some places, but with long distance travel and our large populations, it would be a challenge.

Dark Jaguar said...

Yeah that seems more likely.

St.B said...

First off, tongue in cheek intended… What bad sci-fi, lol?! Those giant brains in Star Trek episode 1, season one, were rockin’!! So they weren’t humans but they granted Capt. Chris Pike his legs and a hot babe. Loved those big veined brains.

As to the question at hand, I agree that we as a species will likely manipulate the evolution, errr.. shifting of our genome. Then it may be said we will have differing types of humans. Those that have been manipulated by man/science and those that have resisted it or were socially or economically unable to take part. Makes me think of Herbert’s Destination: Void series. Gotta love the final book, they are all bitching as to which group is the most human yet when they awake the actual humans, from “cryo-stasis” (I believe), the “real” humans were nothing like what the others had become.

I love the possibilities but have learned the hard way to remember this mantra… “Beware of the monsters you create.”