Sunday, April 12, 2009
Does ingenuity slow down evolution?
Humans and to some degree our hominid ancestors had the remarkable ability to cope with natural selections pressures using ingenuity. Natural selection did not produce more efficient bodies for our ancestors and us because we were smart enough to evade those selection pressures using tools. In fact we still have a knee joint and spine characteristic or four legged mammals. Homo-sapiens have not evolved in the last 30 thousand years in terms of anatomy. Has our ingenuity allowed us to bypass selection to the extent that our evolution has slowed down or ceased? Or are we just evolving in different, less noticeable ways? Try to use specific characteristics to develop your argument.
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Oh, Vikky I'm lovin' the prompt.
ReplyDeleteHere's the dizzle...
In my opinion, our ingenuity is the greatest evolutionary advantage there is, regardless of kingdom, phylum or taxa. We, human beings, have the remarkable ability to change our environment to better suit our bodies! We create homes and cities all to create a perfect environment for us thrive in, and thus our species has conquered the planet. All other organisms must evolve in order to survive in a changing environment. But humans create homes with heating units and lightbulbs, so that we do not have to sit out in the cold darkness at night. The closest nonhuman example of this I can think of is how certain chimpanzees use rudimentary tools to extract termites from their hives as sustainance. These simians use non biological tools to change their environment, which is the ingenuity to which you refer.
Of course, if there ever were some sort of mass-destruction of society, humans would have to physically evolve in order to remain extant. I do beleive that humans are evolving in less noticeable ways right now, however. I am sure that our brain chemistry has evolved to take in large quantities of information over the time that we have existed on the planet, especially because of the information culture that humans have always lived in. I beleive that especially now there is a great evolutionary trend that is beginning regarding our intelligence and creative potential: both are increasing.
"Descent with modification." - Darwin
ReplyDeleteI believe that we are still evolving at the same rate even with slight modifications in terms of "ingenuity." Mutations still occur at the same rate as they did 10 million years ago. The amount of data taken down upon this concept has only been recorded for the last 100-150 years - obviously not enough time to notice many distinct changes. Australopithecus had a smaller head than Homo sapiens with time for evolution to occur. The amount of data that is taken down notices few to none changes at all because time still has to run its course. Rome was not built in a day (although it did not take millions of years). I would agree that ingenuity may have veered off evolution a tinge but not much at all. Ingenuity may have just changed the premises upon which natural selection acts. Instead of natural selection causing the fittest in the "hunting" situation to survive, it is now having to deal with mutations in terms of those who have sickle-cell disease to prevent malaria or cystic fibrosis. The environment itself has changed. We are no longer continuing warfare with other beasts for food - we are fighting a warfare with bacteria and viruses. Darwin's main ideas on natural selection included:
"Natural selection is differential success in reproduction (unequal ability of individuals to survive and reproduce).
Natural selection occurs through an interaction between the environment and the variability inherent among the individual organisms making up a population.
The product of natural selection is the adaptation of populations of organisms to their environment," (Campbell 435).
Natural selection is just the driving force which so to say "weeds" out those who are unfit to survive in the "war." Ingenuity has protected humans from other beasts but again, it has just changed the battlefield. The biological theme of natural selection is crucial in understanding this topic.
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ReplyDeleteOn the contrary Mr. Baruah, I think that instead of slowing down evolution, human ingenuity is working with natural selection to change the course of human evolution. Throughout the course of anthropology, we have long observed a change in the physiological evolution of hominids even with the introduction of tools. For example, Homo habilis, arguably the first of the genus Homo, had a cranial capacity of less than half of Homo sapiens. Also, basic tools such as crude axes and knives have been found among Homo habilis remains, which indicate that they too had ingenuity. This does not mean that Homo habilis all together escaped natural selection, but rather changed them to become different. In this case, natural selection favored the enlargement of the cranium, which has the obvious selective advantage of increased intelligent power that could lead to almost endless opportunities for increased survival and reproduction.
ReplyDeleteIn your prompt, your main argument is that there has been no major physiological changes in Homo sapiens in the past 30,000 years. To this I reply that 30,000 years is the proverbial drop in the bucket in terms of geological time necessary for major evolutionary changes to occur. I am actually firmly convinced that Homo sapiens are undergoing evolution just like all species and that it will take many more thousands of years for us to actually determine what physiological changes are being favored. I would like to point out, going in the strain of my Homo habilis example, that it took about 1.3 million years, if not many more, for Australopithecine to become Homo habilis. This estimate of years is based off the earliest dating Australopithecine and Homo habilis fossils, so it is quite likely that it took even more time than that. Going by this time table for evolution, Homo sapiens still has another million or so years before we can be classified as an entirely different population.
In my opinion, I think one of the first physiological changes will be the complete loss of the appendix. Also, based on past hominid evolution, I believe that the overarching theme of future hominid evolution will be further enlargement of the cranium.
Overall, Vikram, I think the problem with modern humans is that we do not understand the full scope of time necessary for evolution to take place. That is why there are so many skeptics of evolutionary theory, and that is why some may believe that technological advances are going to block evolution. Technology will merely create new selective pressures that are different, but not roadblocks, in hominid evolution.
sorry about the above deletions and such. My word processor was having a rough time copying over paragraph separations, and it still can't copy italics
ReplyDeleteVikram is correct in his assertion that technological advances will block evolution. Goone's argument contains valuable points, however, we must look at the process of evolution as a whole to gauge the effect that technology will have on evolution.
ReplyDeleteNatural selection is the process by which organisms attain a selective advantage, which in turns becomes a common trait over time, thus leading to the evolution of a species. For example, studies on Lucy, a fossilized hominid of the species Australopithecus afarensis, show that our ancient ancestors had relatively large heads, and as a result, most offspring died during birth because their heads could not fit through the birth canal. The only "survivors" of birth were those hominids that had smaller heads that could pass the birth canal. Therefore, over time, the "small-head" phenotypic trait was amplified by the continued existence of smaller headed hominids, making the selective advantage a common trait. This is the process that has taken place time and again to ensure our evolution to this very day.
However, what would happen if most of the larger headed hominids survived? If the Australopithecus afarensis were as intelligent as we are to figure out Caesarean section, coupled with precise medical equipment and sterilization of surroundings, they could have easily saved the lives of so many of their offspring. Now, the chain reaction takes place. If many larger headed hominids lived past birth, surviving and reproducing, then the small-head gene would be lost in the gene pool amidst the genes of a majority large-headed population. The "small-head" trait would not be amplified, although it is a selective advantage, and as a result would not become a common trait. If the Australopithecus afarensis were as intelligent as we are, then all births of those hominids would have taken place via C-section, eliminating the need for the development of a smaller head. Evolution would thereby be hindered.
It is true, as Goone mentioned, that early hominids WERE intelligent, and used "crude axes and knives", however, drawing comparison between those rudimentary tools and the greatly advanced technologies of today is almost absurd. The pace of technology has reached a point where it bears full capability to hinder evolution, TIME INDEPENDENT. The weak of our species, those diseased and disabled, are able to survive far beyond their time of death due to medical and technological advancements. For example, those with Diabetes mellitus type 1 can take injections of artificially produced insulin and continue living, instead of dying shortly after birth. There is a genetic vulnerability that comes with contracting this type of diabetes, and the continued existence and reproduction of those with diabetes mellitus type 1 limits the potential for a human species that has genetically eradicated any possibility of having juvenile diabetes.
As stated previously, the technology of today bears full potential to limit, and even block evolution, for we can extend the lives of the less fit, shattering the principle that is "the survival of the fittest".
Sources:
ReplyDeletehttp://en.wikipedia.org/wiki/Human_evolution#Genus_Homo
Early humans and their world
By Bo Gräslund
http://naturalselection.0catch.com/Files/Early%20Man.html
http://en.wikipedia.org/wiki/Lucy_(Australopithecus)
http://en.wikipedia.org/wiki/Juvenile_diabetes
Quite ironically, contrary to your point I recently read an article that humans are evolving ten times faster than they were 100 years ago, and that humans are the fastest evolving mammals due to the pressures we ourselves create. For your point that humans have not changed in the last 30,000 years, I find that argument very flawed. Several key examples is the majority loss of body hair (compared to our ancestors), the disuse of the pinkey on your foot, and the importance of an intelligent species. Just the simple fact that we as a species are basically required to know how to read, do mathematics, problem solve and understand complex situtations shows to what great extent we have evolved in 30,000 years. I doubt you could of taken an ancestor from even 12,000 years ago and managed to teach him basic algebra in his life time, let alone calculus by the age of seventeen.now compare to how much smarter a wolf is to its wolf ancestor 30,000 years ago; not much I could gaurantee you. Not only that, but due to technology the large population we currently have in our species only assists evolution in the context of variety, and we'll have to simply let time do its thing and watch as the stronger of us survive and reproduce and the weaker die off.
ReplyDeleteAs for our ingenuity, it itself is a limiting factor in evolution. The smarter civilizations managed to find a way to survive and be dominant, passing their genes along to their ancestors, while the weaker, stupider races got killed. For examples you don't see any trojan ancestors running around, but the greeks are a nice, healthy, vibrant civilization :). It is our ingenuity which forges our path of evolution, ingenuity itself being a trait, and those civilizations with more of it being able to survive, flourish, and reproduce to their heart's content.
I never stated that humans have not changed in the last 30,000 years; I'm guessing that remark was at Vikram, Boris.
ReplyDeleteBoth Boris and Sam Pearl note that intelligence is in itself an evolved trait. This is indeed true, and something I did not notice before. I also agree that the evolution of the human mental capacity and general intelligence is highly exacerbated in today's complex and relatively more intelligent society compared to previous times. However, in most other physical realms (non-intelligence related), there is still a definite potential for technology to limit evolution.
For example, if some scientist of the future develops an artificial antibody that is twice or three times as effective as the natural antibody, and this antibody is injected into humans in large quantities, then eventually, our immune system would lose partial function, and may even evolve to enhance the performance of the artificial antibody. Our immune system would not evolve into a greater body defense system, but rather a "side-kick". In this manner, human technology could limit the extent of evolution.
Goone did mention in his post that we, modern humans, do not understand "the full scope of time necessary for evolution to take place". I DO understand that it takes a very, very long time for a selective advantage to become a common trait, but it is highly unlikely that the evolution of our intelligence will cease or move in the opposite direction. As such, if technological advancements, such as the aforementioned antibodies, were injected into humans over very long periods of time, them surely evolution could be limited.
Yes Vikram, I think it does. However, all of us must be careful and stating what our intelligence and technology affects.
ReplyDeleteWhen talking about the evolution of homo sapiens, I think it’s fair to say that evolution has taken a new twist because we have used medicine and technology to save the disabled and the diseased. With our agricultural technology, we can feed people who otherwise would have died of starving, saving people whose traits may have been otherwise selected against. Geographical evolutionary pressures have also been overcome by humans, allowing different races to reproduce and, essentially, remixing the gene pool. The evolution of humans into separate races shows the first step in species differentiation, but that’s where airplanes came in and now an African man could have a Chinese spouse. In that case, I think the path of evolution has changed drastically, but I don’t think we can discuss the “rate” of evolution of humans because we simply can’t measure it. As Goone and Vissagan pointed out, humans have been around for too short a time and especially since the industrial revolution, there is no way we can measure evolutionary change in ourselves because natural selection has a had a very limited role in recent human history.
Our technology and intelligence has also given us a lot of power. Humans are at the top of their food chain(s) and that gives us tremendous ecological power. That’s because we have the power to create evolutionary pressures for other species. For example, rapid deforestation may be forcing thousands of species to extinction, but at the same time, it may be selecting for a particular species or a group of species. In that case, humans have definitely increased the rate of evolution. Hence, we must be careful when we’re talking about human intelligence and its effects on the rate of evolution.