Looking at a domestic dog as opposed to a wolf and they barely resemble on another yet genetically they are the same animal, Not all of these physical changes happened because they were selected for. These physical changes started appearing when they were selected for behavioral traits. Is it safe to say that humans will also or possibly already have experienced physical changes because of changes to the society we live in,
Domestic dogs display neotenic features; that is, the normal development of mature features in wolves and other wild canids are retarded in the domestic species, making them appear more pup-like. This is both because we breed dogs for the ‘cuteness’ of immaturity and for submissiveness, and so many breeds of modern non-toy dogs look like wolf pups, and of course the highly manipulated toy and ‘companion’ breeds have features that are decidedly detrimental for wildland survival.
This is probably true to a certain extent for humans as well, although the division of this between evolutionary pressures, epigenetic modifications to gene expression brought on by the modern diet and lifestyle, and environmental effects are so interlinked that it would be very difficult to clearly delineate the impact of one effect from the others except in very narrow contexts. We have certainly lost the strength of our brachiating evolutionary cousins and have grown much larger brains with complex language-processing ability, but a lot of features of the ‘modern’ human are a result of sitting around watching Netflix and eating microwave popcorn instead of digging grubs for sustenance and bashing rocks together to try to do the magic of ‘fire’.
The two effects that lead to changes in one trait when a different trait is under selection are
Genetic hitchhiking - Wikipedia
Pleiotropy - Wikipedia
In addition, of course, physical changes can just be attributable to chance.
Genetic drift - Wikipedia
If you’re asking if this can be inferred from what’s happened to dogs - no, not really. The genetic principles involved are universal, but dogs have been subject to incredibly intense artificial selection with population bottlenecks, where a breeder will ensure that one or a few individuals are the progenitors of an entire subpopulation of dogs, which are then prevented from breeding with other subpopulations to eliminate gene flow. The artificial population bottleneck greatly increases the strength of the hitchhiking and drift effects.
Natural selection is generally much slower, and the human population has been much larger (at least since the out-of-Africa bottleneck about 50,000 years ago). Pleiotropy is still in play - if one gene has multiple effects, the effect will not be weakened by slow selection in a large population.
Do we really want to go there? We look at a particular dog and, based on its appearance, decide what breed it is, and based on that breed’s reputation, suspect that it is particularly agressive, or smart, or affectionate, or good at some particular skill. If we do that to humans, that’s racial/ethnic discrimination.
That is true but I was actually thinking a 100 or so generations down the line even more than that. Will we slowly drift off into different types based on our positions in life.
No, not unless we also divide into subpopulations of humans who don’t interbreed. The trend in recent times has been the opposite, toward greater gene flow among subpopulations. Is the probability that you marry someone from Fiji higher or lower than it was 500 years ago? Is the probability that a prince marries an actress higher or lower than it was 500 years ago?
No, because even regressive societies tend to have or evolve enough social mobility for lineages of people to change occupations even notwithstanding social and technological innovations. H.G. Wells wrote about the underling workman Morlocks and the elite decadent Eloi, but realistically even if such a situation could develop the Morlocks would eventually realize that they don’t actually need the Eloi for anything and would just take over their civilization, husband them for meat, and live the good life. A blacksmith’s son does not develop big forearms because of the hours his father spend pounding iron, and of course, there are essentially no professional blacksmiths today anyway because iron and steel products are made by mechanical forges and CNC milling machines.
No, because our positions in life will not be stable for 100 generations. You’re talking 2000 years or more for 100 generations.
Certainly humans, a highly social animal, have self-selected for characteristics suitable to that kind of life. It is a slow process though because our self-selection process is extremely faulty.
There are lessons we may not want to learn from canines, like the poop of other animals being magically delicious.
Space travel might eventually enable human subspeciation. You have groups of humans separated by long distances and under different selection pressures (gravity, atmosphere, etc.). These selection pressures might be quite intense due to the natural dangers. It will be many years before technology allows this level of self-sufficient human isolation, but it seems inevitable as long as we retain a technological civilization (which is by no means guaranteed). Of course, sci-fi writers have been speculating about this sort of thing since forever.
H.G.Wells, The Time Machine. 1895. Besides the time machine, that’s the main plot – after many generations the upper class and lower class (in Britain, of course) become two separate species, the naive beautiful helpless Eloi and the predatory savage Morlocks.
If anything, extended habitation in not-terrestrial environments will likely drive artificial and deliberate genetic and epigenetic modification. What we know from studies of astronauts doing long tours on the ISS, and even long term effects on the handful of astronauts that spent mere days outside of Earth’s magnetosphere is that there are substantial health impacts to space habitation.
We don’t have any real data on health effects of living in fractional Earth gravity on the Moon or Mars but based upon interpolation and “bed rest” simulations space physiologists expect significant detrimental effects from that as well from musculoskeletal degeneration to cardiopulmonary and immune system dysfunction as well as a myriad of other less obvious effects such as hygiene and physiology issues from fomes not settling as quickly in low gravity and blood not pooling and coagulating the way it does in Earth gravity.
When we reach that level of technology, surely biotechnology will long since have made natural evolutionary mechanisms irrelevant to human genetics. By then our genome will be whatever we want it to be.
That seems likely, though the net result will be the same: distinct human subspecies tuned for their environment. Genetic engineering will increase the rate of divergence, but probably not fundamentally change what is possible.
One can speculate on other factors as well, such as the possibility of intense social pushback on human genetic engineering. History suggests that this will not be a serious obstacle, especially if the costs are low enough that everyone can afford to tweak their children’s genes, but you never know. Some kind of serious event, where millions of gene-tweaked people are left with physical or mental disabilities that only manifest later in life, could set things back by decades or centuries.
If we expand to colonize the galaxy, we will lose communication will all but our closest neighbors. So I guess even if biotech allows us complete control over our genome, the effect will be similar to natural allopatric speciation. It may be choice rather than natural genetic drift, but if we don’t even know what choices other populations are making, we cannot make the same choices.
Actually I suspect it will lead to more individual modification and enhancement rather than anything that could be defined along the lines of a biologically distinct species, especially if genetic engineering gets to the point of being able to modify already differentiated tissues and organs (already in its infancy although delivery methods are difficult and unreliable, so it is only used to treat chronic, life-threatening illness). It is easy to go hog-wild on speculation of what that will look like and any guesswork today is likely to be badly wrong, but I could see making major changes up to and including radical changes to the human planform like making fingers with nerve sensors more like octopus tentacles, optical sensors that see far into the infrared or ultraviolet with wraparound visual field, additional organs that provide greater protection and control of immune and hormonal functions, maybe even replacing the digestive system with something more robust and flexible.
The one thing I don’t think will change in the foreseeable future is mental capacity beyond extant human norms; although genetic engineering may permit for skewing the development toward greater intellect, I don’t think we do or will have enough of an understanding of the human brain to make workable functional changes, or do I think we will have machine-brain interfaces that will be capable of reading or translating thoughts (though they may be capable of controlling limbs and other objects, and potentially of receiving additional sensory information through adaptation and plasticity of our current visual cortex). I’m willing to be proven wrong, though.
I don’t think that ethical or moral objections to such modifications will stand in the way of wide adoption if they prove to be functional and beneficial, and in fact the greater concern is the use of these technologies on people without their explicit consent (i.e. in childhood) to produce workers or ‘mindless’ drones a la Huxley’s Brave New World. We definitely need an ethical framework for adopting these technologies through it will have to be flexible enough to allow for some measure of voluntary experimentation and adoption, else it will become a ‘black market’ technology used by unethical people and commercial/national interests without regulation of any kind.
Or, maybe we’ll just nuke ourselves or starve on a planet consigned to the collapse of civilization because of climate change and the death of oxygen-generating ocean life. That’ll be fun, too.
Certainly possible, though with some caveats:
- Will we really be past human tribalism even millennia from now? People that look too different may be shunned. If an entire population is moving away from some baseline, that’s one thing, but individuals may face discrimination.
- There are development costs to consider. A given society might be able to afford a research project to give everyone, say, tolerance to reduced gravity. But to give one person extra fingers just because they want them? We’ll need to seriously increase the efficiency of developing these things if truly personalized genetic engineering is to happen.
- Even if some individual customization takes place, there are still some changes that make sense for everyone in a given environment. Or even just undriven drift, like how fashion or language drifts between populations with no contact.
I’d expect the most extreme environments to also have the most extreme individual outliers. People adapted to hibernation techniques, or fluidic breathing for high-gee maneuvers, etc. They’re already going to be far off the human baseline; some extra mods on top of that aren’t going to concern them.
I basically agree, but if we can turn most people into Einsteins or Feynmans, that’s not a bad start. Totally revamping the neural architecture seems much farther off.
Hence the “as long as we retain a technological civilization” in my first post. Humanity might survive a widespread extinction event, but we aren’t getting a second chance at a technological civilization. We ate the “yolk” of easily accessible hydrocarbons and metal ores already.
Well, pretty close – growing up in a farming community, I often see farmers spreading organic fertilizer on their fields (and even their vegetable gardens) in the spring and fall.
It seems most likely that such ‘genetic tweaking’ will start as an attempt to disease traits that have become common in the population. Ones that previously were kept in check because people with these diseases often didn’t live long enough to reproduce much, but do live that long with current medical treatment.
A personal example: I am diabetic, as is my brother, and was my father, grandmother, 2 uncles, 3 cousins, etc. A well-known genetic trait, worsened by the diet of modern Americans. If a genetic treatment was available for unborn children to reduce the susceptibility to diabetes, most of my family would eagerly choose it. (Might even try to get our insurance company to pay for it – they certainly know the cost of a diabetic policyholder. *)
I can easily see such ‘preventative’ genetic modifications being the first ones widely adopted, and then possibly spreading to more ‘cosmetic’ traits. (Want to choose your unborn child’s hair color? – that’s a big thing in horse breeding – there are whole breeds based on coat color!)
- Of course, I can see Big Pharma & some of the Medical establishment strongly opposing this, just because of how much business it would take away from them.
This is an interesting aspect of developing types. Very often one trait will be selected for and it will usually come hand in hand with another trait seemingly unrelated. Pigeon racers, horse breeders and bird dog breeders are all very aware of this. They often use a particular physical trait to identify animals that will possess a specific behavioral trait.