The future evolution of humans
I've written about some future predictions for human evolution before. A couple of readers sent me this article from Science (subscription required) by Michael Balter, titled "Are humans still evolving?" Here's a sample:
To many researchers, the answer is obvious. Human biology, like that of all other living organisms on Earth, is the result of natural selection and other evolutionary mechanisms. Some say the question itself betrays a misunderstanding of how evolution works. "The very notion that ... [ellipsis in original] we might not be evolving derives from a belief that all other life forms were merely stages on the way to the appearance of humans as the intended end point," says primatologist Mary Pavelka of the University of Calgary in Canada.
But other scientists point out that in developed countries, culture, technology, and especially medical advances have changed the evolutionary rules, from survival of the fittest to survival of nearly everyone. The result, they say, is a "relaxation" of the selective pressures that might have operated 50 or 100 years ago. "Biologically, humans are going nowhere," says anthropologist Ian Tattersall of the American Museum of Natural History in New York City. University College London geneticist Steven Jones agrees. "The central issue is what one means by 'evolving,'" Jones says. "Most people when they think of evolution mean natural selection, a change to a different or better adapted state. In that sense, in the developed world, human evolution has stopped" (Balter 2005:234).
Of course, this article has a purpose in asking the question -- otherwise, there would be no reason to cover it, since the question is a century old. The reason: lots of genes are showing evidence for recent evolutionary changes in humans. Some of these are obvious, such as various molecular defenses against malaria. Falciparum malaria in particular has affected human populations severely only for the past few thousand years, and its very high mortality rate has yielded a vast opportunity for genetic defenses to evolve -- even those, like the sickle cell trait, that have devastating side effects for homozygous individuals. Likewise, some populations have recently evolved the ability to produce lactase, the enzyme that digests lactose, longer into adulthood. This change is an adaptation to diets that contain significant undigested (by microbes) dairy products, and is most common in Northern Europe and North Africa.
Other changes are less obvious but nonetheless candidates for selection. The DRD4 gene has multiple alleles, one of which is associated with ADHD in Western societies. This allele apparently has been increasing rapidly in frequency over the past several thousand years, presumably due to selection on its behavioral effects.
The article takes these recent changes as a case in point that evolution is still happening in human populations. And of course it is correct within the bounds of the examples. The spread of HIV in Africa has likely resulted in strong selection on several molecular defenses, including the delta 32 CCR5 mutation which is currently at 13 percent in Europeans, probably because of past selection from smallpox. Other defenses are likely emerging but unknown so far.
But the potency of this example depends on two observations. First, HIV is so serious a cause of mortality in Africa (and indeed in many other regions of the world) today that the strength of selection resulting from it is high enough to be obvious. And second, mortality due to HIV is very likely to remain high for the foreseeable future -- long enough to constitute an observable trend.
For the most part, the kinds of selection that have been operating in the recent past cannot be shown to be effective today. How many people in Northern Europe are currently dying because of the inability to digest milk effectively as adults? How many Britons does smallpox kill each year? Even trends that currently exist in human health, such as the persistence of malaria and HIV in sub-Saharan Africa, are active targets of medical research and public health efforts. Much is made of the fact that medical science has reduced mortality manyfold from the traditional epidemic killers of large proportions of humankind. Even though this is indisputably true, mortality continues nonetheless, as does reduced fertility for many people. These facts mean that selection continues, particularly upon single-locus genetic disorders. The goal of continued research is to reduce the causes of early mortality, and restore lost fertility to those who want it. Those goals do not by themselves reduce the public health tragedies of today, but they make it very likely that today's maladies will be less severe in the future.
Medical technology has changed massively over the past 100 years, and there is every reason to expect that the change will be just as vast over the next century. This means that diseases that are incurable and unavoidable today will be cured or avoided in the future. It also means that people will likely have much more genetic knowledge about themselves in the future, and may be able to employ that knowledge to alter or manipulate the genes of their offspring in some way. In a previous post I wrote about the prospect of encoding information into genes as a sort of legacy project -- the genetic version of a vanity license plate. This kind of trivial change will join other more potent forms of genetic engineering. In other words, within the next century, the most powerful form of selection may be artificial selection (almost a technological version of meiotic drive) on the composition of genes themselves.
But the power of selection is not the only factor to consider. It is true that the power of natural selection on medical targets is decreasing. And it is likely that the power of artificial selection will greatly increase. But equally important to the prospects for the human species is the persistence of such selection as a trend. Here is where future prediction inevitably fails.
The potency of the article's examples of recent evolutionary changes is that these changes have formed substantial trends over the past several thousand years. If there were no trend, there would be no identifiable selective change, regardless of the strength of selection in any single generation.
If biomedical technology can change by light-years within a century, it endangers the prediction of any future trends. A hundred years is only four generations in humans, far less time than selection needs to have a substantial effect. Selection associated with HIV in Africa today is doubtless very high, but it is unlikely to last very many more generations before medical and economic breakthroughs reverse it. Selection is fast, in geological terms, but in social terms it runs like syrup.
On the subject of trends, we are on safer ground (although never completely so) to discuss evolutionary changes due not to selection, but instead to demography. Medical technology is not the only mode of rapid change in human societies. Social and technological changes have both combined to result in massive demographic shifts in Western countries. Consider that a hundred years ago the population of Europe and America was growing rapidly, with a fertility rate nearly double today's. Now, both populations have fertility rates below replacement, with the United States population growth supported by immigration, and Western Europe and Russia shrinking despite massive immigration. These demographic changes are the cause of strong evolutionary change in each of those regions, by migration and genetic drift, as alleles with a long history in Europe decline in frequency, and alleles from other regions of the world increase. These demographic shifts are almost certain to be much more powerful over the next century than any changes due to selection in those populations.
But selection will likely have a future effect that we cannot predict. There is approximately a one in a hundred million chance that any single nucleotide site will undergo a point mutation between a parent and a child. Across the genome, this means that you likely differ from your mother and father by fifty or a hundred new mutations.
In the preagricultural era, when there were only a few million people in the world, this rate of mutation means that only a small proportion of possible functional genetic changes occurred in any generation. For a population of 10 million, only around 1 in 10 possible sites had any new variants in anybody. Weakly selected changes would be unlikely to increase, even if they conferred a very slight advantage, because genetic drift would likely erase them before they reached an appreciable frequency. In other words, the evolutionary exploration of the genome was very limited. The human population could only move to those variants that were common enough to be selected and advantageous enough to overcome relatively strong genetic drift.
Today, with 6 billion humans, every one-off mutation from the human consensus genome sequence occurs in dozens of people. Many multiple-off mutations occur in some people. In a larger population, selection is more potent, because genetic drift is weaker. This means that the advantageous variants of the next fifty millennia are already appearing in the world today, and may inevitably be selected. The global population is exploring the entire mutational space, many times over, and novel mutations are no longer likely to disappear so rapidly due to genetic drift. Any near variants that confer an advantage are already on the way to fixation. Many of these may lose their advantage once biomedical technology catches up to them. But others will be more subtle, more difficult to market in pharmaceutical form, and these will slowly, steadily increase.
What are they? The level of selection necessary to drive a variant to fixation over 100,000 years or 200,000 years is very weak -- so weak that we will never measure it in a single generation, even if we assess the reproductive performance of thousands of people. So we don't know what those changes are, or which direction the trends will emerge.
Strong trends in selection are opposed by biomedical technology. Weak trends are unobservable. Which leaves us with, precisely nothing. How can we predict a future that is already happening? Is it any wonder people like me spend our time trying to predict the past?
References:
Balter M. 2005. Are humans still evolving? Science 309:234-237.
Getting under your skin
I just couldn't see these two items on Slashdot without connecting them together.
Item A: NTT researchers developed a device to control human movements remotely. The device exploits the "galvanic vestibular stimulation" phenomenon, whereby an electrical current applied behind the mastoid process causes you to lose balance and veer in the opposite direction.
Known as "Shaking the World," the project is the result of research carried out by NTT researcher Taro Maeda. Maeda and his colleagues constructed a headphone-like apparatus to deliver the electrical current and a small radio control to direct the strength and direction of the signal. Whoever wears such headphones can be steered by remote control.
Conference attendees lined up to try to maintain their balance as an NTT spokesperson gently steered them left and right. Some attempted to counteract the current's effects, while others almost ran into the crowd of onlookers as they stumbled haplessly along.
The aim of the project is to make simulators better. Who knows, maybe those old driving simulators for driver's ed would be spiced up a bit.
Item B: Former HHS Secretary and Wisconsin governor Tommy Thompson wants Americans to get RFID implants. The chips are information labels, basically like the ones that you can get for your pets to identify them. Here, they want to have a link to medical information, so accident victims won't get the wrong medications.
Thompson, now a director of Applied Digital Solutions, the company that makes the chips, intends to publish the proposal in the next 50 days, by which time he plans to have had a VeriChip inserted in his arm. Thompson believes the capsules could help save thousands of lives every year.
Or, then there's this:
According to Procter, the chips can also be used for financial transactions. In Europe, the Baja Beach Club chain has introduced chipping in the Netherlands and Spain.
The VeriChip is inserted at the club and means club-goers will no longer have to wait in line to pay to get in and will be able to use the chip to pay their bar bill.
Some people are worried that people will be pressured to get these in these days of terrorism for greater security. Myself, I'm worried that some Japanese scientist will figure out a way to make me jerk around like a deranged puppet.
802,701 A.D.? A little short of that
UPDATE (2007/10/28): I wrote this post last year (the original datestamp is October 18, 2006), to critique some reports about what sounded like crazy future predictions made by an "evolutionary theorist" about the future.
Well, undead stories seem to rise from their graves this time of year, and the headlines say it all:
Penises to get bigger, breasts to get perter
Human race to split into elite and ugly species 11000 years hence
Paris Hilton and Lindsay Lohan Recruited by Al Qaeda!
OK, that last one has nothing to do with the story...I just thought I would go for the traffic trifecta!
All right, last year's post (reproduced below) does a good job of addressing this silly story. I haven't link-checked it, I would assume some of last year's stories will have gone dead. This year's versions (linked above) are essentially the same.
In the last year, the essay author, Oliver Curry, has come out on his website to let us know his work had been selectively quoted in last year's press accounts. I point that out here in the interest of accuracy, although after reading his essay, I still think that the basic scenario is all wrong.
The irony is that there are many stranger things that will likely happen to humans in the future, not only as a result of genetic engineering but also plain-and-simple natural selection.
ORIGINAL POST:
Why, oh why do we have to deal with things like this?
Human species 'may split in two'
Humanity may split into two sub-species in 100,000 years' time as predicted by HG Wells, an expert has said.
Evolutionary theorist Oliver Curry of the London School of Economics expects a genetic upper class and a dim-witted underclass to emerge.
The human race would peak in the year 3000, he said - before a decline due to dependence on technology.
People would become choosier about their sexual partners, causing humanity to divide into sub-species, he added.
The descendants of the genetic upper class would be tall, slim, healthy, attractive, intelligent, and creative and a far cry from the "underclass" humans who would have evolved into dim-witted, ugly, squat goblin-like creatures.
No, no, no, no, no! Not gonna happen. Nope. No way.
In the November Scientific American, notable skeptic Michael Shermer has a column that muses on the famous Wolfgang Pauli proverb, "This isn't right. It's not even wrong."
Not even wrong. What could be worse? Being wronger than wrong, or what I call Asimov's axiom, well stated in his book The Relativity of Wrong (Doubleday, 1988): "When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together."
To my mind, this is a case like that. Some people would probably argue that we simply cannot predict what the course of human evolution will be like thousands of years from now. The possible range of events is so great, ranging from genetic engineering to environmental catastrophe to space colonization, that any guess will certainly be wrong.
But that does not mean that all guesses will be equally wrong. Some of them will be more wrong than others -- the "world is flat" kind of wrong. Some will be, well, spectacularly wrong.
Like this stuff. Let's survey some quotes from different stories:
News.com.au: "Human master race is on way."
The Age: "HUMANS will grow to an average of two metres, live to the age of 120 and all have brown skin by 3000, an evolutionary expert says"
Independent Online: "Men's willies will be bigger and women's boobs will be more pert - by the year 3000."
New York Sun: "The analysis of technological, biological, and environmental trends suggests H.G.Wells may not have been too far off the mark in his novel "The Time Machine," in which mankind splits into a frail, wealthy genetic upper class and a downtrodden, ape-like worker class."
Zager and Evans: "In the year 5555, your arms are hanging limp by your sides. Your legs got nothing to do. Some machine, doing that for you."
OK, that last one has nothing to do with this story. But it's just as good a prediction!
Now, what makes these claims so wrong? When humans evolve into whatever they will ultimately become, they will do so because of natural selection. That means that people with some allele have to stop reproducing, or reproduce a lot more, or just die young.
We can start with the dying young -- basically, it ain't happening. To be sure, there are some alleles that are at low frequencies right now that will never, ever get to higher frequencies because they make people die young -- and by young, I mean, too young to have children. But those alleles are almost all at low frequencies already, so saying that they will never reach high frequencies is no great change.
Let's look at the Morlock prediction, this from the Sun article:
Dr. Curry predicts that 100,000 years from now, mankind will be divided into two distinct subspecies, with a genetic elite moving in ever more exclusive circles. The genetic upper class will, he argues, be increasingly tall, thin, symmetrical, clean, healthy, and creative, while the genetic underclass will be short, stocky, asymmetrical, grubby, unhealthy, and less intelligent.
OK, so if medical technology progresses to allow people to evade natural selection and evolve weak alleles, then why will they be unhealthy? Shouldn't they be super-healthy? If people are mating assortatively so that the beautiful always mate with the beautiful (and the ugly with the ugly), and if the ugly are unhealthy, then how do both the beautiful and ugly survive? In 100,000 years, even a miniscule difference in their intrinsic rates of increase would cause one to displace the other entirely.
I mean, at least H. G. Wells had an answer for this one -- the ugly were farming the beautiful!
And what accounts for the selection in favor of the asymmetry genes? If you're going to talk about ugly hermit-like humans, you don't have to go all literal and make them like hermit crabs!
Let's use some common sense, here. Domesticated animals depend on humans to survive. They can't evade predators in the wild. But they aren't unhealthy by any measure, not compared to their wild counterparts. Depending on humans works. We depend on technology. It works. It has worked for two million years. It hasn't make us asymmetrical and stumpy.
And why "short and stocky"? I just don't understand.
There is assortative mating by height now, and probably has been for a long, long time. But no human population has diverged into separate short and tall races. That's not because people at the short and tall ends face selective disadvantages. It's because people in the middle have at least as many kids as people at the extremes.
The point is that assortative mating doesn't cause population divergence. The population divergence here would necessarily be sympatric (unless all the ugly incipient Morlocks were shipped to an island), so it would require natural selection against intermediate phenotypes. But there is no reason at all to think that such selection would occur. I mean, really -- can you imagine that the most symmetric would have lots of kids, and the least symmetric would have lots of kids, but the people in the middle of the distribution would have none?
This is the "not even wrong" part. The whole scenario shows a complete lack of understanding of basic population genetics.
Consider this:
Further into the future, the outlook is less rosy, Dr. Curry argued, with humans declining physically thanks to excessive reliance on technology and medical interventions. By around the year 12000, he believes communication skills and emotional abilities such as love, sympathy, trust, and respect to have diminished, eroding the abilities of humans to care for others or perform in teams.
Now, if you are predicting this, then what you are saying is that the humans who are least capable of communication, love, sympathy, trust, and respect will be the ones who have the most offspring. There's nothing logically inconsistent about this hypothesis, but does it seem in the remotest bit likely? Our "excessive reliance on technology and medical interventions" is going to stop loving, caring people from reproducing? I just don't see the connection.
I don't think the vast majority of people who read this will believe it -- it's the sort of story that runs because it gets folks to chuckle. But, sheesh, if you think this is just as unlikely as any other possible future, you're wronger than wrong!
Ummm...about that "evolutionary impact statement"...
MSNBC is running a series on the "future of evolution," featuring Peter Ward's book Future Evolution and others. Today (5/4/05) was my last lecture day in my introductory course, and I tend to spend time talking about the future direction of human evolution, so the future is on my mind.
The speculations about the future evolution of animal species are frippery, but certainly entertaining:
In "The Future is Wild," [Dougal] Dixon, the British geologist, and co-author John Adams create an animal kingdom in which humans no longer reign.
Dixon and Adams give whimsical names to the creatures they dream up, aiming not so much to predict the future but to show some possibilities.
In their vision, humans become extinct in an Ice Age 5 million years from now. "Shagrats," or giant rodents, and "gannet whales," large aquatic birds, have evolved during this stretch of time.
The Ice Age melts away 100 million years later, marking the beginning of the end of large mammals and giving rise to creatures like the "ocean phantom," a jellyfish the size of a truck; the "swampus," a relative of the octopus that emerges from swamps to feed; and the "toraton," a reptile bigger than dinosaurs.
The more relevant predictions are those of Ward, who envisions the consequences of continued high-density human society on natural environments:
Gone will be the vast grasslands that gave rise to large mammals. "I bet we'll never see a large animal species ever again," Ward says. "Give it a million years," he says, and lions, tigers and bears might all be gone.
Probably true. Even if the current area and density of human habitation was maintained without further increase, the megafauna are probably doomed. Their population sizes and geographic extents are small enough now that a pathogen could easily devastate their population. They might survive this for thousands of years with human help, but large-bodied mammals are definitely not a growth industry. The only way they will be is if we start to farm them. Of course, in light of their natural lean content, this might be a good idea.
The article also talks to Stephen Palumbi (Stanford University)
"Anything that works we like to do more and more and more of," he said in an interview, noting that in the case of vaccines, insecticides and herbicides, that means short-term gains against disease and pests only to see them develop a resistance and come back even stronger.
Palumbi does see a "movement towards greater awareness" of such dangers and suggests that society take them into account much as it does significant environmental changes that come with development. "There's no reason we couldn't do an 'evolutionary impact statement,'" he says.
This idea appears to be focused on the impact of transferring genes across species barriers. Of course if we could rationally estimate unforeseen consequences of such transfers, they wouldn't be unforeseen. And there is no sense at all in trying to estimate "worst-case scenarios" if no regulation is ever shaped around preventing the worst possible cases from happening.
In the case of genetic engineering, the main problem appears to be that it is fast. The MSNBC article raises the point that dog breeds have evolved tremendous diversity under human influence. Any population geneticist knows that with a few hundred generations of strong selection, it is probably possible to make anything that a genetic engineer could conceivably manufacture. Sure, a genetic engineer could in principle replace many hundreds of genes and create major phenotypic reorganizations, but in practical terms this is almost certainly not going to create a functional organism. Our problem isn't that we can't make the breeds we want through old-fashioned selective breeding, it is that we want results faster, and implanting a bacterial gene into corn is the fastest way to go. If the resulting seeds can't be saved and replanted but need to be bought every year from the supplier, more the better. So filing an "impact statement" for evolutionary changes is a little overwrought, unless we are going to send federal agents to the Westminster Dog Show to stop the breeding of Ch. Miss Fuzzies Snoop of All Doggz.
Lead with your gut
Another article in the series focuses on diet changes and obesity in an evolutionary context. This one is straightforward science, citing Loren Cordain, whose work I have previously described. Cordain is the author of The Paleo Diet, a health book focused on the qualities of hunter-gatherer diets. It's a NeanderThin for the new generation (except of course that NeanderThin is the NeanderThin for the new generation). There's also The Origin Diet, if you're counting.
Modern life may have solved most of our food-gathering problems, but human evolution has not kept up. Our bodies are still wired for hunter-gatherer biology: Eat all the food you can and store it -- in body fat -- in case your supply of food runs out, as in the case of famine. A dangerous configuration for a society with all-you-can-eat buffets.
Somehow people never seem to mention that the great "caveman" diet that kept us so healthy in the Pleistocene HAD EVERYONE DYING BEFORE 50! Instead of French Women Don't Get Fat, we could just as easily be buying Erectus Women Didn't Get Fat, which would almost certainly omit the likelihood that THEY LIVED WITH CONSTANT HUNGER AND FREQUENT STARVATION.
Bill Leonard makes an appearance:
"What I think we can say conclusively, is that the evolutionary success of our species is ultimately a nutrition story," says Bill Leonard, chairman of Northwestern University's anthropology department.
A high caloric intake isn't so much to blame as an imbalance between calories in and calories out. Though developing nations generally consume fewer calories than industrialized nations, Leonard found subsistence societies that match developed societies calorie for calorie. The reindeer-herding Evenki people of Siberia consume more than 2,800 calories a day, and far more animal foods than the typical American, yet have lower cholesterol and body mass indicators.
As does Henry Bunn:
Along with nearly universal access to food, the modern economy has allowed an unprecedented number of Americans to survive using our big, evolved brains and little else. We're getting fat off our own evolutionary success and, says University of Wisconsin paleoanthropologist Henry Bunn, "I don't think biological evolution has really had a chance to react."
It's a very nice piece of journalism, really, citing most of the right people. I recommend it.
Disease in the future
As for my class, what prediction came up today about the future of humanity? Disease load. Compared to historic levels, today we have a pretty low pathogen and parasite load. We accomplished this by eliminating pathogens directly (smallpox), by changing the circumstances that allows pathogens and parasites to spread (sanitation), by killing pathogens directly (antibiotics), and by training our immune systems with foreign antigens (vaccination). These changes have had a pretty radical effect in increasing human survivorship, especially for kids. Assuming that technology continues to get cheaper, these changes will continue to spread to the developing world and cause great improvements in human health.
The evolution of resistance is a never-ending problem. Not only can bacteria become resistant to antibiotics, but mosquitos become resistant to pesticides. And commensal species like H. pylori and E. coli are affected by the same antibiotics that treat disease, leading to changes in their populations and the potential spread of pathogenic variants.
The outcome of this technological battle is likely to be the increased tolerance of pathogen load in humans. We are already seeing this with treatments for HIV infection. The drug cocktails that delay or prevent the progression of the disease don't cure it or eliminate the pathogen. Instead they restrict the pathogen population to low numbers that the body can tolerate as a chronic infection. This is the goal of many medical treatments--making chronic conditions manageable with medication, rather than curing them. It is what leads many people to take long-term courses of antacids for their chronic H. pylori infections, and why people are looking for pathogens that influence heart disease, diabetes, and other chronic conditions.
The thing is that we have already figured out how to fight most of the pathogens that have immediate impacts on health (if imperfectly in many cases). The ones we are encountering now have greatly delayed health impacts, and not always for the worse. The story with H. pylori is an example in point: although some strains present a higher risk of gastric ulcers or cancer, they may also have benefits in regulating acid levels. So the medical problem is finding the best balance of benefits and drawbacks, and that involves not antibiotics to eliminate infections entirely, but other kinds of medications to regulate the microbial signaling interactions.
In other words, we are no longer defeating most diseases; we are using our technology to live with them, and in some cases to exploit them. And we face every likelihood of seeing many new pathogens in the future, through human-animal interactions (avian flu), through the emergence of resistant pathogen strains (Staphylococcus) and perhaps through the deliberate introduction of bioengineered pathogens in to human populations (anthrax?). It is even possible that we will see the reemergence of viral genomes that have long been incorporated into the human genome as a product of our evolution.
I predict that these changes will mean that future people will live with greatly increased pathogen loads compared to today. This will be a return to what for many human populations was the Pleistocene norm: long-term, low-impact infections. Except instead of being regulated by selection and consequent mortality, the system will be regulated by chemicals and biotechnology.
Other predictions are welcome, and I'll be happy to post the best ones!
I can't end better than Peter Ward, though:
'"I get tired of futurists so missing the mark, or so it seems to me," he says. "First, there is the sense that humans will soon be gone, or second, that we will produce some 'Blade Runner' world that is all pollution and Michael Jackson mouth masks."
Taming the domestic frontier
An opinion column in the Seattle Post-Intelligencer by Vincent G. Barnes (Friday, Feb. 11, 2005) makes an interesting argument about the uses of genetic engineering. The basic point is that there may be a lot of money to be made in creating customized plants for use in suburban yards. The column raises the possibility of fall foliage in colors like violet or blue, and grass that grows only two inches and then stops.
Of course some of these miracles are already available through good plant choice and breeding. Many of the yards in Western Kansas where I'm from are buffalo grass, which really does stop at around three inches, and wouldn't need mowing at all except to keep the weeds down. But my yard in Wisconsin grows six to eight inches a month in the summertime, and buffalo grass doesn't work in this climate, so I can see the point of genetic alterations.
I think this probably will be a growth industry in the future. Homeowners don't have the same necessity for pest-resistant plants and high-yield crops as farmers, because they lack the scale to make such innovations really economical. But grass is an area in which large landowners and commercial installations would begin to see an economy in easier lawn care, and the development for those purposes would translate to products for residences. But then, it would be an interesting problem to work out just how a genetically engineered strain of grass could be maintained on a yard, since the smaller plants would probably do poorly in competition with wild-type plants that could grow much larger and collect more energy to spread.
As far as herbaceous plants go, most homes that include them in their plantings do so because it is a hobby of the homeowner--they are just too labor intensive to do without taking an interest in them. I would guess that some kind of labor help--like personal yard robots--would be necessary to make economies of scale on non-grass plantings practical. So the columns suggestions about sprucing up maple trees or fall colors would be maybe the first areas in which genetic alterations would become practical for landscaping plants, just because trees and bushes are the least labor-intensive: you just plant them once and forget them except for pruning and watering, and even those aren't strictly necessary.
Kurzweil interview: The Singularity Is Near
Regular readers know my interest in future evolution. Of course in some senses the future is unknowable, especially over the evolutionary time scale.
But over the shorter term, a lot of people think that technology will fundamentally alter humanity. The only thing is, these people never seem to agree on what form that alteration will take.
One of the most prolific futurists is Ray Kurzweil. One of his fundamental assumptions is that the technological progress toward artificial intelligence proceeds exponentially. Anybody who's seen an exponential curve knows that after a critical point, things start to change really, really fast.
InstaPundit is running an interview with Kurzweil, touching on his book The Singularity Is Near: When Humans Transcend Biology.Here's an excerpt:
Arguably we already have powers comparable to the Greek gods, albeit, as you point out, piddling ones compared to what is to come. For example, you are able to write ideas in your blog and instantly communicate them to just those people who are interested. We have many ways of communicating our thoughts to precisely those persons around the world with whom we wish to share ideas. If you want to acquire an antique plate with a certain inscription, you have a good chance of quickly finding the person who has it. We have increasingly rapid access to our exponentially growing human knowledge base.
And there's this:
Our biological thinking takes place at chemical gradient speeds of a few hundred feet per second, millions of times slower than electronics. And our communication speeds are at the speed of human language, again millions of times slower than what machines are capable of. Of course, our language ability has been very important -- other animal species don't have species-wide knowledge bases at all, let alone exponentially expanding ones, and the ability to share them.
...
A key insight here is that the nonbiological portion of our intelligence will expand exponentially whereas our biological thinking is effectively fixed. When we get the mid 2040s, according to my models the nonbiological portion of our civilization's thinking ability will be billions of times greater than the biological portion. Now that represents a profound change.
Some interesting thoughts on the nature of intelligence and its relation to power, some facile thoughts on the history (and prehistory) of technological change, and some fairly frightening thoughts about the chance that spambots will ultimately colonize our brains.
That's why I don't enable comments in my brain, either.
Human evolution "at the crossroads"
MSNBC has posted a new entry in its series on "future evolution," this one covering possible scenarios for the evolution of our species in the future. This article is a concoction of wide-eyed speculation and slightly cautionary unconnected facts.
The basic story of the article is the fairly predictable idea that humans are going to look more similar to each other in the future:
At least for modern-day humans, the forces that lead to species spin-offs have been largely held in abeyance: Populations are increasingly in contact with each other, leading to greater gene-mixing. Humans are no longer threatened by predators their own size, and medicine cancels out inherited infirmities ranging from hemophilia to nearsightedness.
All of this is conventional wisdom, but I wonder how much of it is actually true. The effect of medical technology certainly does tend to cancel the selective impact of certain medical conditions, but that can hardly be said to reduce human genetic variability--instead it probably increases it. Likewise, the threat of predation has little to do with population differentiation, unless some of us have had to run a lot faster to escape from predators than others (aside: my voice recognition software inserted "creditors" instead of "predators," which of course demolishes my point).
The main fact supporting their idea of greater genetic uniformity in the future is the idea that populations are mixing with each other. By any measure, there are many times more people moving between large human populations today then would be necessary to make them much more uniform in the future than they are now. The rate of migration between populations necessary to support the current level of genetic difference is only one or two individuals per generation. Today we see many millions of people moving among large populations in every generation. Given this large scale human movement, many populations likely will become much more similar to each other.
But I wouldn't be so sure that this hasn't been the case in the past also. One or two people moving between populations every generation is not very many. If there many times that many people moving between populations today, it seems likely that the and there were all so many times as many moving between populations in the past. Some of the current genetic differentiation of populations is likely due to local selection in different places. That local selection may have changed in today's populations--it may even have disappeared. But we really don't know whether some of these factors remain, or whether new ones have arisen.
The prediction that human populations will become more similar depends on the assumption that selection has become everywhere uniform. But there could be very powerful selection on human populations right now that nevertheless has such slight effects in any one generation that we can't measure it. A selective advantage of less than one percent increased fitness in every generation can completely transform a population within a few thousand years. Yet such a small advantage would require the observation of reproduction in thousands of individuals to measure accurately.
The point is a simple one: we can't know what's going to happen in the feature because we can't measure what's happening now. Not only does our uncertainty depend on unexpected events that we can't predict, it also depends upon unobserved phenomena that are happening right now.
Can we say that humans won't speciate in the future? I think we can say this only to the extent that we believe that we haven't speciated in the past. If human nature really tends to extend our reproductive horizons across the boundaries of populations, as I think it does, then it certainly would seem unlikely that these horizons would be greatly reduced in the future.
On the results of a human speciation, the article says this:
Even in the event of a post-human split-off, evolutionary theory dictates that one species would eventually subjugate, assimilate or eliminate their competitors for the top job in the global ecosystem. Just ask the Neanderthals.
Of course there is no reason to believe that the competitive exclusion principle need operate in a cultural system like that in which humans are embedded. There is no conceptual barrier to accepting different species of humans coexisting. Nor is there necessarily a practical barrier. Although I'm not a member of this camp, there are many anthropologists to believe that humans coexisted until very recently with different species occupying different environments or even the same environments at the same times.
Even so, culture is a powerful force determining human behavior, so that the imposition of extreme cultural isolation upon a group, coupled with our likely future technological capacities, might lead to the rise of reproductive isolation. Consider an extreme religious sect with strong rules against intermarriage with other groups and access to the techniques of genetic engineering. How easy would be for this group to enforce its policy of isolation by including genomic elements in its members that would make reproduction with other humans impossible? Today this is an unknown answer, but it is unlikely to remain unknown for long. It could be that such a "speciation" would be reversible, if the genomic elements preventing reproduction could be removed. Or it could be permanent, with additional engineered elements serving as a sort of religious library of encoded information in the genomes of the sect's members. Who will be the first human to have the full text of a religious document inserted by genetic engineering into his or her genome? That person may have already been born.
Capturing our genetic legacy
Much of the article is concerned with the possibility that humans will increasingly incorporate robotic parts, becoming cyber-humans. This has little to do with human evolution per se, but it does include this interesting quote:
"When you talk to people in the know, they think cybernetics will become biology," [University of Washington paleontologist Peter Ward] said. "So you're right back to biology, and the easiest way to make changes is by manipulating genomes."
Really this gets down to the basic issue of whether and how humans will control their evolutionary future. If we continue to allow the independent assortment of genes as a random process, there will always be a random component to our offspring. But if people can pick which specific alleles they want to be expressed in their offspring, and can have those choices error-corrected to make sure that mutations don't occur during the reproductive process, then randomness is potentially gone. Certainly people want their offspring to be like them in general, but does this mean that you want your offspring to have all of your qualities? Today, those of us with biological offspring accept the fact that each of them will get half our genes--hopefully the better half, but possibly the worse half. Yet even today this is far from universal. Many people with giving hearts adopted raise children biologically unrelated to them. Others manage their infertility with the use of donor eggs or sperm. Parenting is not a statistical relationship, nor should it be. If the question is, "How many genes out of 20,000 must you share with your offspring in order to love them as a parent should?" then the answer is already zero.
On this issue we can safely say that our population is already prepared for the concept of introducing unrelated alleles into the conception of individual children. Assorting the alleles are already in a parent to choose one or more qualities of the offspring is barely genetic manipulation. What's really happening is the preservation of the genetic material chosen by the parent into the next generation. The intent need not be solely functional. A parent might choose to transmit a single noncoding genetic region to all of his or her offspring, like a bar code indicating the family crest. We could call it "assisted genealogy."
From the standpoint of introducing a permanent genetic changes in the populations, this kind of procedure--stacking the deck of statistical change--certainly is evolution. Indeed, it is merely an extreme case of meiotic drive. But in this case, the drive would often be in favor of healthy alleles against disease-associated alleles. If it were possible, humans would be exerting powerful purifying selection against some of their own alleles. The effect would be to increase the representation of some of their other alleles in future generations, ultimately by reducing the genetic variation in human populations related to reproduction.
At the same time, choosing the alleles of your offspring has the potential of making the diversity of human genomes as great as the diversity of human cultures. For some, this would have the positive effect of reinforcing cultural heritage. For others, it would be merely another venue to exercise bad taste. Lest you think that people will always choose what is best for their children, consider some of the extraordinarily bad names that people choose for them. One of the advantages of not messing with nature is that nature regularly outperforms human judgment. Will we in the future see the birth of children with highly exaggerated features of one kind or another? Will we see professional athletes selling snippets of their genetic code to parents hoping for the next Joe Montana or Babe Ruth?
From a legal standpoint, this last question raises an interesting issue. Presently under U.S. law, individuals have no rights over their own genetic code. In particular, companies and other individuals may use your genetic code or material for any purpose, even to the extent of obtaining patents for the exclusive use of your genetic code. But if the genome becomes a record that parents can use to codify information within their offspring, by deliberately incorporating certain genetic sequences, then the genome would be operating more like a book than a machine. In particular, the genome more and more appears to be software rather than hardware. As such, it may be subject to copyright. Can you assert copyright on year-end genome? An athlete or scientist wanting to sell parts of his or her genetic sequence to prospective parents certainly would hope so.
A prediction for the future: our genomes increasingly confirm the maxim that every person is a work of art.
Recent evolution and future evolution
Wired has a short article by Annalee Newitz about recent evolutionary changes and their implications for futurists:
"I think my work is changing people's ideas about evolution, because now natural selection seems to have continued all the way up to the present day," said [Jonathan] Pritchard. "There's no reason to think it stops now."
That's why futurists like [Ray] Kurzweil are excited about Lahn and Pritchard's work -- it could lay the foundations for a new understanding of evolution that's more tolerant of the idea that humans should intervene in their own genetic transformation.
[Bruce] Lahn is comfortable with this idea. "If there's an evolutionary advantage to be had by using technology, then people will do it," he said. "People are going to start changing the game in evolution in ways Darwin never anticipated."
Trans-humanist pundit James Hughes, author of Citizen Cyborg, thinks it's time to speed up the evolutionary process.
"You can take what nature gave you, but there's no good reason to take nature as a guide for where you should go in the future," Hughes said.
Now, that's an angle I hadn't thought of, and I've been thinking about this a lot. But it does make sense -- there's nothing inviolate about being human in the way we are now, since humans keep on changing.
John Hawks Department of Anthropology
University of Wisconsin—Madison
Copyright © 2007 John Hawks