Are humans still evolving? Absolutely, says new analysis of long-term survey of human health
October 19, 2009Although advances in medical care have improved standards of living over time, humans aren't entirely sheltered from the forces of natural selection, a new study shows.
"There is this idea that because medicine has been so good at reducing mortality rates, that means that natural selection is no longer operating in humans," said Stephen Stearns of Yale University. A recent analysis by Stearns and colleagues turns this idea on its head. As part of a working group sponsored by the National Evolutionary Synthesis Center in Durham, NC, the team of researchers decided to find out if natural selection — a major driving force of evolution — is still at work in humans today. The result? Human evolution hasn't ground to a halt. In fact, we're likely to evolve at roughly the same rates as other living things, findings suggest.
Taking advantage of data collected as part of a 60-year study of more than 2000 North American women in the Framingham Heart Study, the researchers analyzed a handful of traits important to human health. By measuring the effects of these traits on the number of children the women had over their lifetime, the researchers were able to estimate the strength of selection and make short-term predictions about how each trait might evolve in the future.
After adjusting for factors such as education and smoking, their models predict that the descendents of these women will be slightly shorter and heavier, will have lower blood pressure and cholesterol, will have their first child at a younger age, and will reach menopause later in life.
"The take-home message is that humans are currently evolving," said Stearns. "Natural selection is still operating."
The changes may be slow and gradual, but the predicted rates of change are no different from those observed elsewhere in nature, the researchers say. "The evolution that's going on in the Framingham women is like average rates of evolution measured in other plants and animals," said Stearns. "These results place humans in the medium-to-slow end of the range of rates observed for other living things," he added. "But what that means is that humans aren't special with respect to how fast they're evolving. They're kind of average."
More information: Byars, S., D. Ewbank, et al. (2009). "Natural selection in a contemporary human population." Proceedings of the National Academy of Sciences 106(42). doi: 10.1073/pnas.0906199106
Source: National Evolutionary Synthesis Center
Jul 18, 2008 |
not rated yet |
0
I never though of that in evolutionary terms. I know oppression is increasing but never linked it to devolution
@dirk_bruere -- haha!! So true! I've always thought this, makes me sad in ways :/ but I'm too optimistic to think out future laid out by the ignorant.
Yeah, it's weird isn't it. You would think that a trait such as high intelligence ought to be favourable in any kind of future scenario... especially since the so called "trade off" (bigger brain, less power for other stuff) already happened.
Evolution is not a forward backward thing. There is no goal for evolution so there is no forward or backward.
Interesting stuff!
Evolution does not require creation of a new species. A single species can evolve without creating two separate species. Evolution can DRIVE the creation of separate species but it is not the only marker. Genetic change in a population is evolution.
May I remind you that the folks in the country, like myself, are far more intelligent than your generalization of incorrect facts. May I also remind you that the graduation rate of 'rednecks' vs city folk is staggeringly in our favor. I demand an apology from your despicable sense of humor.
Funny, the pupils in 'redneck' states do much better in national standardized tests than their counterparts in the big cities... Strange that they manage this even though the average funding per student is about 2/3 of what those in the big cities get.. You are clearly an idiot with an unwarranted sense of arrogance. Who knew Armstrong, Farnsworth etc. were unevolved...
There never was a "first person to speak English". All natural languages are the products of linguistic evolution, comprising components of a lot of other languages. E.g. Latin: ex-agere, populus, species, arbitror, prae-vius, evolvere, lingua, persona. E.g. Greek: terma, organo, drama.
Indeed, I got it wrong. Sorry.
There is no goal for evolution
---------------------------------
Then how about each of us -of one species- setting for ourselves the goal to become a non-violent, tolerant, careful and compassionate being?
Imagine one goal, achieved 6 billion times. Now, THAT would be evolution...or the end of it.
However perhaps the evolution then moves to sociological traits. As it could be asserted that one's societal attributes now affect who successfully passes on their genes and have offspring who successfully reproduce and so on. Which since there's so many facets of society, this evolution can take many forms, behavioral, economical, etc.
But regardless of the form, does evolution (sociological) now take place on an individual level then, as societal attributes are not (as easily/commonly?) passed on through genes as biology/phenotype, etc? i.e. the societal phenotype is determined more by environment and society and ultimately the individual.
It then becomes every individual's responsibility to evolve themself i.e. chaman's post?
There are multiple meanings of 'evolution'. The meaning used in the title of this article is the weakest: namely, a shift in proportions of phenotypes in a population. Unfortunately the ambiguous word often misleads the uninformed, who conclude that the above study provides support for a natural origin of complex functions, systems, and major taxa.
Just so we're all on the same page, is this as opposed to the informed, who assume a supernatural origin of complex functions, systems and major taxa?
So what meaning should be used to best communicate it's authenticity to the general public and the doubters?
True, but what is the limit of that speciation event? I don't believe that event can be considered anything than a horizontally based microevolution event.
[Evolution can DRIVE the creation of separate species but it is not the only marker. Genetic change in a population is evolution.]
Yes but what is the origin of the genetic information hidden in the codons of the genome in question? Undirected mindless forces of mutation and natural selection could not by themselves have built the genetic info content, that I believe comes from a Mind of such magnitude might as well invoke the name of God as the author of the evolutionary process. That is not a scientific conclusion but a philosophical/metaphysical one based on logical conclusions of existing data. The assumption of purely natural forces minus any intelligent designer is also a purely metaphysical one.
Apparently, people on this site are tired of being belittled by unthinking stereotypes perpetrated by people with no sense of their own bigotry.
If the standard of female beauty remains tied with BMI, depression and social anxiety rates are kept on the rise, pornography, prostitution and recreational drugs proliferate, we're safe. The media has been making sure of that for a while now.
Cultural/sociological trumps biological, as far as reproduction is concerned. That should be the large-scale picture. 2000 females over a 60 year period isn't a large-scale picture.
Pornography, prostitution, and recreational drugs increased rapidly in number and amount over the last 10000 years? History as well as the Bible tell us a different story.
A low BMI in yonder times meant illness and a burden for the community. Only some generations ago progress finally allowed us to see slim women without worrying. The popular appeal of slimness is just a temporary reaction to eons of mistrust.
Of course not. I'm referring to the last few decades. As the speed of culture propagation increased explosively, social trends have begun to predominate biological ones.
That is not to say that we have stopped evolving biologically, just that the main driving forces are no longer biological in nature and as such, we can't make accurate predictions based on them.
And since this topic is drawing some hot tempers, let me say also that I do not discount some form of intelligent design, I just don't see it evident within the process of evolution. But then, that's why so many "bible thumpers" (generalization, not accusation) try to discount evolution.
Perhaps we will be able to answer these questions within our life time, I personally can't wait to find out who is right.
That statement is not backed up by any scientific reasoning. You _believe_ that genetic content can't be created by natural selection. Via evolution, it can (and by definition), has to be.
ID fans consistently fixate on mutation as a random process and pretend Natural Selection IS mutation. Which where Pete falls down.
Natural Selection comes AFTER mutation. It is simply a name for the inherent culling by the environment of any changes that decrease an organism's chance of reproducing. Any mutation that increases an organism's chance of reproducing would tend to be preserved. This is how the environment affects the information in the genome.
The other thing people tend to not know is that some mutations consist of duplication of parts of the genome. The duplication makes it possible to have an unmodified copy and a modified copy of a gene. Thus allowing the amount of information in the genome to increase.
Ethelred