Science

Afternoon Inquisition 10.23

Natural selection and genetic drift are the mechanisms that drive and control evolution. Natural selection is the process that causes heritable traits that are helpful for survival and reproduction to become more common in a population, and harmful traits to become more rare. Genetic drift is a process that produces random changes in the frequency of traits in a population, and over time can cause substantial changes in organisms.

All things being equal, what specific traits might humans need nature to select for to better adapt to the environment?

And just for fun, what traits would you select for and what drifts would you cause, if you were in control of human evolution?

Sam Ogden

Sam Ogden is a writer, beach bum, and songwriter living in Houston, Texas, but he may be found scratching himself at many points across the globe. Follow him on Twitter @SamOgden

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56 Comments

  1. I’d add improved temperature control. Improved orgasm rates for women (wink) – hey, that’s adaptive right? Right? We need it to, um…

    I’d get rid of eye problems because not being able to see without glasses or contacts it just annoying.

  2. FALSE DICHOTO… oh wait, sorry.

    If I were in charge of human evolution, I’d push skeletal development to be all cartilage, like sharks.

    Because I think a whole planet full of people with floppy bones would be good times.

  3. Okay, seriously this time.

    Knees, because the ones we have now are crap.

    Back, same as above.

    Better immune systems. Able to fight off any diesease that is transmitted via viruses or bacteria.

    Brains, smarter, less gullible, less likely to confuse causation.

  4. “All things being equal, what specific traits might humans need nature to select for to better adapt to the environment?”

    Sorry, Sam, I don’t understand this question. Could you elaborate? I think you mean something like “where do you see natural selection taking humans in the future, as they adapt to their changing environment?”. …But I could be wrong… and if that is what you mean, I don’t think I like the question.

    You seem to have a grasp of evolutionary theory, so I think you’re aware that natural selection isn’t “survival of the fittest”, but “survival of the fit-enough”. …And, clearly, we (humans) are fit enough for our environment. So I don’t see an natural selection taking place–as governed by our environment–at all.

    That said, there are other sources of evolutionary pressure. Parasites, for one. Sexual preferences, for another. And, in our (sociological) case, one could make very strong arguments that natural selection within humans is favoring those who believe in the likes of “go forth and multiply”, and against those of us who feel “no kids is fine, one kid is enough, two is maybe acceptable”.

    So… uhhh… like I said, I’m not quite sure what you’re asking for the first question.

    As for the second question, duh: critical thinking.

    And frikkin’ lasers for eyes.

  5. @Gabrielbrawley:

    I was thinking backs and knees, too.

    I threw out my back the other day and have been hobbling around, cursing upright bipedal motion ever since. And my knees just seem to hurt more and more with every passing year. Of course, I’m not especially kind to my body. I’m not gentle with it, which could be the problem. But extra strong backs and knees would be cool.

  6. @JRice:

    I just meant that since when don’t really know exactly how the environment is going to change, we should only do the speculative exercise about our evolution with everything else staying the same. Perhaps I could have worded it better.

  7. @Sam Ogden: Same here. I have always treated my body like it was industructible. It isn’t. It is very destructible. I would like a ball and socket joint for knees instead of a pocket of liquid and some strings.

    Backs just suck, I don’t know what to do about them. Maybe super strong abs.

  8. For backs, why not a straight spine instead of one that is curved. That curvature is the cause of back problems.

    Other ideas:
    -get rid of the appendix
    -no more myopia, hyperopia
    -Actually, let’s just remove all genetic diseases from the gene pool.

  9. -teeth without all the little crevices that get food stuck beyond the reach of a brush.
    -a rigid channel for the sciatic nerve to pass through, so that it doesn’t get crushed between pelvis and butt-muscle so often.

  10. From reading the responses above, I have a question – doesn’t evolution “want” us to die earlier (i.e., not live longer)? … The more iterations of breeding, the greater the rate of evolution …

    I believe social evolution will probably trump any biological evolution – e.g., our altruistic dispersal of medical advancements (like glasses, contact lenses) …

    Or how about the fact that our society brainwashes us to finding certain things attractive that may not be the best in terms of positive evolution in terms of survival of the species – e.g., skinny with good hair, as opposed to intelligent, physically strong, or better able to bear children (not to imply there is a false dichotomy or anything).

  11. @Sam Ogden: It could probably look like any of those. A very rigid skeleton is only really useful if you’re going from gravity to microgravity and back again, but you still need some kind of structure, so the cartilage framework is probably a good compromise i we’re talking a permanent switch. It would also solve most of those knee and back problems.

    I think I’d like a circulatory system with a less centralized pumping mechanism, so that microgravity wouldn’t cause all dem fluids to collect in the torso. If I’m really going nuts, I’d want some kind of a bellows mechanism that could collect air and then squeeze it out under pressure, to provide locomotion without touching a hull or other structure.

  12. @TheSkepticalMale:

    doesn’t evolution “want” us to die earlier (i.e., not live longer)? … The more iterations of breeding, the greater the rate of evolution …

    Maybe, but I’d at least like to feel strong and healthy and breathe underwater ’til evolution kills me.

  13. Humans are still an invasive species in all civilized parts of the world. Until we get some significant selective pressures that aren’t intraspecies (e.g. not sexual selection or resource competition within the species) we aren’t going to change much genetically.

    That said, I would like us to evolve the ability to feel the pain of everyone in, say, a 15 foot radius. Maybe, then, we could learn to be tolerant.

  14. @Gabrielbrawley: Kinda-sorta. I like your “ontogeny recapitulates phylogeny” thinking, but that’s actually kinda old-school in biology circles these days. We don’t form gills, but we do form folds at about the same stage that fish form the folds. Ours turn into our jaws and ears, fish get gills. …So… not quite gills.

    Still pretty cool, though.

  15. @TheSkepticalMale: The second two points are good ones. The first one is wrong, though. Evolution doesn’t “want” anything. But you knew that. What I mean to say is that evolution doesn’t favor any particular rate of adaptation, as long as it’s “quick enough”. Also, death has nothing to do with evolution: the only thing that matters is birth. Evolution–if we’re happy personifying it–would be happy if you were immortal, as long as you had kids often enough. You’ll just die off when the environment no longer supports your traits.

    Also, it’s worth considering that not all evolutionary changes are necessarily “good”. For example, in light of the above statement, it would be “better” if we reached sexual maturity sooner. But we’re “paying the price” of slow maturity (meaning: it was acceptable genetic drift) in order to enhance other features that were environmentally advantageous… in this case, probably larger brains and greater social capacity.

    When trying to teach evolution to people, the one point that everyone should walk away with is just that: it’s not better, it’s adequate. Huge difference. There isn’t enough emphasis on this.

  16. @JRice: Okay. I didn’t know that. I thought we started to develope gills and then reabosbed them before they became permanent. Hurray I have learned something today. My quota is met. Let the drinking commence.

    You seem to have a handle on this so I’ll ask you. I was taught in my human biology class that we all start out as females and it is a massive dump of hormones that change some of us to males. I was also taught that this is why males are more prone to birth defects. Is that still the current view?

  17. As for traits I’d like to manually push evolution towards, after curing cancer and minimizing debilitating diseases (without removing deafness/blindess/dwarfism/etc, where these cultures have their own richness), I would make an asshole that didn’t smell like one.

  18. @JRice: You point is well-taken (the answer to my first question) … But with respect to the statement “death has nothing to do with evolution: the only thing that matters is birth,” is this really true in a world with limited resources that is bulging at the seems?

  19. @Gabrielbrawley: That’s a bit beyond my ken (I’m not great at human development), but:

    Yes, we all start out morphologically female (genetically, of course, we are what we are). At some point during gestation, males express certain genes. (Our penis “drops”, as they say.)

    However, that’s as much as I know. I can’t imagine that it’s specifically the formation of male anatomy that creates more male birth defects… but I can (without being an expert on the subject) say that men do, in fact, have a few more genes… so there’s more room for genetic errors.

    Still, statistically speaking, that’s only 1/46th of our genetic makeup (and, though X is quite a bit larger than Y, still only a portion of that 1/46th), so I would expect maybe a 2% increase in frequency of genetic birth defects in men versus women (and many of those might be less than obvious).

    There are others in our group who probably know loads more about this topic: I’ll leave that to them.

  20. From a purely practical basis, I would also like perfect eyesight, as well as the ability to grow back limbs, all newt-like.

    As for the fun bit, I would like a sense that allows you to sense electromagnetic fields and, like an electric eel, possibly manipulate them. Actually, an even cooler iteration of this would be if this sense was controlled directly by the brain, as opposed to through the nervous system. That way, we could use some sort of electronic system to (wirelessly) interface directly with the computer, and feel responses at the speed of thought!

  21. I keep getting stuck on the “what might happen next” part of all of these suggestions. In the case of removal of all genetic diseases, that would be a very bad plan. I want an evolution where the strong enough survive, not where every life is equally strong.

    But, I’ll play along: Instinct. I wish our “instinct” would catch up with our technology. If it did, we might not fear “other” so much anymore, or might more rationally reproduce.

  22. We need to grow smaller. Seriously. Reduce the average height by about 6 inches each. Smaller people consume fewer resources and produce less waste. Remember, a linear change in height produces a cubic change in mass — just by shrinking about 6 inches we could make a huge difference in the burden we place on the planet’s resources.

    And when you consider that only a couple hundred years ago, the average European male was around five feet tall, this is an entirely achievable goal within a few generations. (Well, actually, that’s more an issue of plasticity than evolution, but the principle is the same.)

    Likewise, we need to bring our appetite/digestion/metabolism more in line with our actual nutritional needs.

  23. @Howard: I think I disagree with your statement that

    a linear change in height produces a cubic change in mass

    I see many people who are short but quite massive. I am quite tall but I regularly interact with people who are as much as a foot shorter than I am but are just as massive.

  24. @ Gabriel: Well, that was a bit sloppy, wasn’t it?

    I think I’m confusing a couple different things. I’m not really sure of the math, the more that I think about it.

    Hmm… Okay. Assume a perfectly spherical person with the density of water, 1 meter in diameter. If my crappy math is correct, that person would have a volume of 4,190,000 cubic centimeters, or a mass of 4,190 kilograms. Now, if you shrink this spherical person by 10 centimeters, you get a mass of 3,050 kilograms.

    In other words, a 10% change in height equals a 27% change in mass.

    So, for example, I’m a pretty short, massive guy. If I shrink my height by 10 percent, and everything else remains proportional (e.g., keep the same BMI), then I’ll still reduce my mass at nearly three times the rate I shrink my height.

    * Okay, on preview, I realize I probably should’ve used a cylindrical person instead of a spherical person. I blame poor body image.

  25. Oh, crap — my math is wrong. I used diameter instead of radius. I thought 2 metric tons was a bit much.

    Here’s the correct[?] values:

    1 meter aqueous sphere-man: 523 kilos

    90 cm aqueous sphere-man: 268 kilos.

    Difference: 255 kilos.

    Percent difference: 49!

    That still looks mighty wrong to me. I need to step away from the spreadsheet before someone gets hurt.

  26. @Howard: The math isn’t that straight forward. Smaller people need to consume more per cubic unit of size. This becomes more obvious when thinking about heating very large amounts of water (a pool) and small amounts (a tea cup). Although it takes longer to heat a pool, it retains it’s temperature all day.

    I wonder if larger people would actually be a better way to spend resources. It works for elephants and whales!

  27. I vote smaller. (In fact, I considered saying as much earlier). Regardless of caloric intake versus size, it’ll make travel (including space travel!) less expensive, plus we can fit into tighter spots, which would mean more places to explore.

    …But I still think, on the whole, it would be less food consumption. Perhaps not “per head”, but certainly “per person”.

  28. That didn’t come out right. I mean:

    10 billion small people would certainly eat less than 10 billion big ones.

    So: smaller. …As long as we don’t use it as an excuse to make more bebbez!

  29. We need to evolve into nicer people. Surely the species would benefit.

    If I was in control however, I would just ensure that I would develop a cure for my diabetes and my flatmate would develop serious double chocolate chip cookie baking abilities. Specifically in that order.

  30. I’d go for flaps of skin, extending between the wrist and abdomen, which can be extended to frighten creationists.

    Oh, yeah, and there was that other thing such things could be useful for…

  31. @a.real.girl: Doesn’t modern medicine thwarts that “culling of the herd” mentality? And if we could solve it genetically, wouldn’t be heaps less expensive in the end (I assume)?

    I guess I’m having trouble seeing how any “ideal” scenario would involve quite so much suffering. I’d be quick to agree that overpopulation is a threat… but I’d like to see quality of life for those of us who have to at least include a predisposition toward healthiness.

    Errr… put another way:

    Whaddayamean by “the strong enough survive, not every life is equally strong”? : )

  32. Photosynthetic skin that absorbs in the infrared spectrum. It would take care of food supply and mitigate the effects of global warming. Of course, visiting Venus would make you fat.

    Also, I’d like to be able to safely drink salt water – water supply.

  33. Better knees, better back, better brain and more and better orgasms and gthe capacity to have all that and more in a weightless environment with a significantly reduced likelihood of any diseases.

    So why is it that Science Fiction is so appealing to those who don’t believe in an afterlife???

  34. Sam – noted your pain, back, joint and otherwise…. Just to note, I have a dog with back and joint problems (Hip Dysplasia) – it isn’t limited to bipeds.

    My wish-list… ability to regrow limbs and damaged organs, brains that don’t go bad with age, and the ability to enjoy the world as it actually is without reference to imaginary supernatural beings.

    JBS

  35. All things being equal, what specific traits might humans need nature to select for to better adapt to the environment?

    Well, since we can’t predict future environments, it would be good for us to have broader capacities to accommodate a wider range of ecological settings. Even in the settings we live in now, without modern technology, if we’re exposed to the elements, we kinda suck at survival when exposed and without supplies to make things to protect us. First line of defense against exposure was already mentioned – we don’t really have a great temperature regulator and we can’t stay in the sun very long at all (especially me – maybe this is a problem genetics gave me that I’m especially bitter at that bitch over … the nerve of giving me so little pigmentation!). Some of us need darker skin.

    Of course, this leads to the problem of needing paler skin in some parts of the planet, so perhaps we need something we can extend out from our bodies to absorb some of the sun’s rays. I vote for wings. This is a multipurpose addition, of course, and would have to be very flexible, so that we would have great steering and we could turn them upside down without moving the main part of our bodies. The posterior would be the protective, dark layer and the anterior would be pale. Thus, when we needed to absorb some sun’s rays so we can produce our vitamin D, we can just flip our wings over. The wings (like these) may also help with a cooling system for us due to their flexibility. We could use them as shade and/or we could perhaps fan ourselves with them.

    Another method for keeping cool would be if we were really nocturnal animals. I mean, seriously, being daytime animals forces us to be out in the hottest part of the day and we sweat to keep cool (though, that’s a feature we have to keep, but would hopefully acquire a better scent) but nocturnal burrow animals don’t have to rely so much on that because the ground they burrow into is moist and cool, like a sweaty bar on Saturday night. How is that not an improvement, eh? I had considered trees before thinking of burrows, but trees are not a universal planetary resource and burrows tend to be easier to find on more places on land (although they don’t seem to work as well in swampy areas). The only problem with burrows for us is, some things in the ground may bite us or other things in the ground (like the chemicals we’ve put there) may be poisonous to us.

    Of course, I also want some gills. I mean, I totally understand how biased we are as land animals to the point that we get all giddy and excited when thinking about when animals started exploring the land with their cute little someday-will-be-hands-with-opposable-thumbs fins, but now we can’t even survive on over three-quarters of the planet without putting a bubble of air near us somehow. This is uncool and inefficient. All the cool kids want the efficiency of gills or built-in airtanks (the latter of which would make us expend more energy while swimming and/or die if it bursts, so is a bad idea …. scratch that one).

    And if, after things get extremely hot, things get extremely cold? Well, if we’re nocturnal, we need a better way to keep warm. Fur is heavy and feathers are too cliche. Unfortunately, I don’t know of a great answer to this … maybe since the cellular nature is part of what makes styrofoam so nifty as an insulator, we could manage to create a lighter version of hair by our bodies being evolved to make hair bubbles of some sort that would coat, perhaps, the topside of those wings I mentioned. If we had it there, our bodies could remain hairless, then and we could just wrap up in our wings for warmth!

    A few other good ideas people mentioned were more efficient brains and … um … ok, I think my imagination ran out.

    And just for fun, what traits would you select for and what drifts would you cause, if you were in control of human evolution?

    All of the above and a spasmatic muscle in the human groin that allows the male penis/female g-spot to vibrate.

    (I hope I’m still as cool as the other geeks after posting this)

  36. If I was in control, I would initiate a change in the most primitive and fundamental areas of the human brain, in order to change the human mentality from one that is naturally self-centered, to one that is naturally other-centered.

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