Slashdot Mirror
Humans Evolving Faster Than Ever
Kwyj1b0 writes "In a massive study on genetic variation among humans, researchers found that most changes have occurred in the last 200 generations, too fast for natural selection to catch up. Recent papers show that rare genetic variations have a more drastic effect than previously believed. Another result shows that 'we carry a much larger load of deleterious variants' (as well as positive variants) than our ancestors 200 generations ago."
Acquisition of mutations is not evolution. Evolution is the combination of variations AND selection of those traits that increase fitness. The fact that we only acquire more genetic mutations means that selectionhas gone down and evolution with it. The simple explanation is that healt care enabled us to cheat on selection.
If an experiment works, something has gone wrong.
200 generations, not 200 years. The difference is a factor of 20 or so.
....but I think we all know where evolution is headed.
All those babies surviving is something of the last five, maybe ten generations at most. And that's in the Western world. TFA is talking about 200 generations.
Actually, this is how evolution works, so "Survival of the Fittest" is still applicable. If the current environment allows those individuals to reproduce and pass on those traits, they are the most fit. We will be a bunch of fat-ass couch potatoes eating chips watching CSI-dancing with the honey boo boo. Just as if the weather turns bad and only gingers can survive, then they are the most fit. Evolution does not care how the fittest are created, whether by man made environments or by natural influences. My favorite story is the American Indians who believed that albinos were unfit. The Albino Indians were considered inferior and were left behind when the warriors went on hunts for meat. Of course being left behind meant they were left with the women to procreate which meant more albinos. In this case the albinos were more fit and evolution favored them. Perhaps you do not so much believe in evolution as you do as creating a master race? I doubt I need to tell you where that leads.
The frightening aspect of this is that population may expand its genetic diversity to fill the 'fit enough" gene pool. Then it will overflow the "fit enough" gene pool by creating mutations that can't survive even with health care, bringing survival back down, albeit with increased genetic variety such that many can't survive without constant medical treatment.
That is to say, we will evolve to require medical treatment.
7500 years, which is basically "modern man" in terms of evolution
We're a young species, but not quite that young. In anatomical terms, ~250,000 years seems to be about the line for "modern" as far as we can tell from fossil evidence. This looks more like a function of agriculture than anything; our hunter-gatherer ancestors may in fact have been healthier in most respects than their descendants, but they couldn't sustain anything like the population density farmers can.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
I think population dynamics show that in times of plenty (little natural selection, abundant food) populations explode, what the human population has been doing the last 100+ years. It's the spring that doesn't come or massive outbreak of disease or new dominant predator that culls the population, when that selection occurs the random genetic variations may give rise to competitive advantages. It is only after the population goes through the selection event that any mutations that proved advantageous will spread right through the population, then the population has evolved. Before the selection event the population is just randomly diverging.
Absolutely true!
Evolution works that way: In good times, a big population is generated that has great genetic variety. When bad times come along, the bad genetic variations will be removed from the population.
Suppose for instance that suddenly tomorrow all oaktrees had pollen that is deadly to most humans. The genetic variations builtup over the last 200 years might have provided a (possibly small) percentage of the population that is resistant to the deadly pollen. The result would be that a small group survives and starts working on a new gene-pool.
Yes, genetically we have been living in "good times" the last generations. More and more "slight defects" in the genetic pool are able to survive into mature ages.
A friend is totally colorblind. A genetic disadvantage, you'd say? Nope, his "grayvision" is a LOT better than that of most of us. Apparently he can spot camouflaged army-material from way further away than us normal people. When suddenly THAT becomes a winning trait (i.e. those that don't have it die), his descendants will form a larger part of the population.
This expansion of the gene pool also allows for combinations. Suppose the guy with the super-vision marries the gal with the super hearing?
Nonsense. Survival of the fittest is still occurring, it's just that the fitness criteria have changed. As you say, "babies that would have died lived on" -- but mostly that happens for those parents who have either the money or the health insurance (and the medical facilities) to deal with what would previously have been an "unfit" baby. Natural selection continues through societal means: the costs of birthing and raising viable children are inversely proportional to the health of the baby; children with difficulties are more expensive to raise.
There is still selection pressure, but in developed countries it's coming more from societal sources than from environmental sources. And the societal pressure isn't so worried about things like good eyesight or height, or those sort of physiological characteristics; it's about access to health care (whether that comes from parents with money or states with social safety nets).
And I would argue that even though humans are in charge of the programs and policies that affect these new fitness criteria, they are still fitness criteria because they are being applied to populations, rather than to individuals (except in very special and statistically insignificant cases). So, survival of the fittest is still alive and well, and being implemented inadvertently by human policy.
That's okay. In about a generation, everyone will be cyborgs anyway. Seriously, Intel plans on shipping 14 nanometer chips in 2013; 5 nanometer processes are under development already, and at that point we can start seriously thinking about using the 5nm process to make machines to make utility fog.
Your natural body is just a device for building a brain and a pair of gonads, at that point, and selective pressures only work on it in this scenario are those that render cyborg-you sterile, destroy your brain before it can be transplanted into a cyberbody, or make you better able to talk a partner into raising a family with you.
depend on your environment sometimes. For example, heterozygous mutations in the gene that lead to cystic fibrosis probably increase resistance to cholera (by lowering electrolyte loss in the gut). Eliminate cholera in the modern world and the advantage apparently disappears. Similar for sickle cell anemia and malaria (depending of course, where you live or travel, this may still be highly relevant for you). And "fit enough" has always been good enough throughout evolution.
This is probably why primates need vitamin C, since we all lived in an environment with plenty of it and there was no selection against loss of the gene which occurred in one of our ancestors.
It is sometimes difficult to see the advantage of a particular mutation (resistance to dioxins because cytochromes don't metabolize them) or other mutations which are only beneficial in combination with others. Mutations in FoxP2 http://en.wikipedia.org/wiki/FOXP2 plus others probably led to human speech. There are rare individuals with mutations in a gene which regulates LDL (the "bad" cholesterol) http://en.wikipedia.org/wiki/Familial_hypercholesterolemia#PCSK9 that have very low LDL levels and are apparently perfectly healthy. They lack a gene most of us have and can eat a "modern" diet with a dramatically reduced cardiovascular risk. This is one of the ways in which speciation occurs.
As usual, theocratic dogmas, rigorously enforced, frequently have unintended consequences. In the case of the dogma of heterogeneity there is the unintended consequence which evolutionary dynamics calls "horizontal transmission". Horizontal transmission is a mode of evolutionary success is based on, what in the vernacular we might call, "hit and run": The evolutionary fate of a stationary system (organism or ecosystem) is decoupled that of another, temporarily co-located, but mobile, replicator.
The result is always the same: The mobile replicator's evolutionary optimum is to totally disregard the viability of its temporary "partner" since it does not share in the fate of the "partner". This relationship is sometimes called "parasitism". That, in an age of jumbo-jet air transport, we might see such evolutionary dynamics play out is as inevitable as it is "sinful" to even think about.
The religious dogma demands that heterogeneity be thought of as evolving only "symbiosis", not "parasitism". This would be the case if there were no escape route for the immigrant replicators -- as they would be forced into "vertical transmission" which, in the vernacular means "sleeping in the bed you made for yourself (and others)". Even if we were somehow able to shut off further migration after allowing immigration, the costs of evolving symbiosis are profound: The vast majority of the immobile heterogenous ecologies resulting from the initial period of immigration would include at least a few replicators that might be thought of as "defectors" in an evolutionary prisoner's dilemma. Therefore the vast majority of ecologies would experience at least pathology if not death outright.
Seastead this.
It's left as an exercise for the reader to make a joke about Pakistan, Utah or Rotherham.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
If this discussion is any indicator, it's devolution that's accelerating.
This statement appears to reflect a misunderstanding of how evolution plays out in practice.
The way evolution is often taught is that the small genetic changes in each generation make a difference to the evolutionary fitness (relative to his/her peers) of the individual right away, but that the changes are so small that it takes very many generations to see divergence of sub-populations of the species and hence noticeable evolutionary change.
The reality of evolution - "puntuated equilibrium" - is different from this simplistic teaching model. What really happens is that genetic changes accumulate over very many generations but don't have much if any immediate effect on evolutionary fitness since in practice these small, incremental, personal changes are often not what drives evolution. What really drives evolution (per the inference of the fossil record) is when the *environment* (weather, food supply, disease, competitors, etc, etc) changes, often very quickly, causing accumulated genetic change to suddenly become relevant... what had previously been a benign genetic change (disease resistance or susceptibility, etc, etc) no suddenly becomes a huge change in evolutionary fitness in the new environment, and and the fate of different genetic subpopulations becomes very differnt (we see visible divergence).
This is "punctuated equlibrium" - long spans of no visible evolutionary change (equilibrium) are puntuated by brief spans of rapid visible change as accumulated genetic drift suddenly becomes relevant due to environmental change.
So... the notion of 200 generations being too quick for "natural selection to keep up" is bogus. Natural selection mosltly doesn't happen every generation - it only happens when those infrequent major environmental changes occur.
Evidence that evolution has escaped you.....
"The hands that help are better far than lips that pray." - Robert Ingersoll (1833-1899)
Evidence that evolution has escaped you.....
No, he's just one of those with a much larger load of deleterious variants.
Ezekiel 23:20
trolololol
Millions of years of genetic variation has produced....this
My ism, it's full of beliefs.