In Darwin’s Origin of Species, he argues that the most fit creatures will be the ones who are most likely to survive and produce offspring. This notion makes perfect sense. When a creature is given a genetic characteristic that makes it easier to feed itself or flee from its predator this characteristic will likely be passed on to future generations. However, when Darwin’s concept is applied to current humans it is very confusing. In other words what unique traits in humans are allowing them to survive better than other humans. Things that once mattered such as good eyesight, strong bones, or any other physical or mental traits no longer appear to affect a persons chance at reproduction. If these traits no longer matter then what factors affect the evolution of humans? Darwin’s theory is based on the idea that the most fit creatures will survive but with advances in medicine and the ability to correct physical deficiencies no characteristics seem to matter to a humans chance for reproduction. However, economic status appears to have become a major factor in reproduction. Lower income households are likely to have more children than a higher income house. Economic situation is not determined by genetics so it is difficult to determine how this situation is affecting the gene pool.
Regardless, Humans are no longer struggling to survive in many parts of the world. Without this struggle for survival is evolution still occurring? When all beings of a group regardless of their specific genetic traits all have an equal chance to reproduce does evolution cease? Then again maybe it is just a matter of time. I think that there is a sweet spot for many species where there is no real direction of evolution because they are nearly perfectly suited for their environment. Once there is a drastic change in the environment evolution in humans will once again continue because specific traits will once again allow certain humans to survive.
I disagree that “Humans are no longer struggling to survive in many parts of the world,” especially with the world “many.” Pulling some facts from http://www.globalissues.org/article/26/poverty-facts-and-stats: “Some 1.1 billion people in developing countries have inadequate access to water, and 2.6 billion lack basic sanitation,” and “1.6 billion people — a quarter of humanity — live without electricity.” Therefore, a struggle for basic existence still affects a huge portion of the population, and those most affected, whose likelihood to live to reproductive age is very slight, will continue to pass down those attributes that facilitated their struggle to that age. Since those economically fortunate have no struggle for existence and will not pass down any particularly advantageous genes whereas those economically unfortunate will pass down advantageous genes, the disparity in wealth might be strengthening the gene pool with modifications suited for survival. By this speculation, after the environment goes to pieces, descendants of the economically disadvantaged will keep the human race intact. Then, as you say, natural selection will once again take the main stage.
ReplyDeleteEvan and Eric both make really interesting points. I think Evan is right that modern advances in medicine will limit human evolution, but I think that this phenomenon only applies to people of means. Certainly, people with access to healthcare rarely die from things like earaches anymore, or even from things like viruses, for which there are vaccinations. These days, if you have money, you no longer have to be the fastest runner, the strongest hunter, or the most temperature-resistant. Most everyone can turn on the heating or purchase prepackaged sustenance in a grocery store. This, I think, will definitely enhance the survival of even the weaker members of society.
ReplyDeleteHowever, I do think that Eric raises a sound objection. It's true that a large portion of humans do not enjoy the cozy lifestyle that we have; in certain parts of the world, survival is still a huge issue. As Eric demonstrates, plenty of people are struggling to overcome famine and disease. And even in the richest of societies, even the best medicine can’t solve everything. For example, many people are genetically predisposed to develop cancer, Type II diabetes, etc. Therefore, I think that natural selection will always be with us; perhaps it’s just slightly limited nowadays.
Evan's last few points about humans reaching a "sweet spot" in their overall evolution are very fascinating. I was too thinking about this part of Darwin's study and also applying it to other species in the world. The amount of "modification" depends upon several factors and is not necessarily constant. However, Darwin points out one consistency: "the individual in its complex struggle fro life, so the degree of modification in different species will be no uniform quantity" (351). The consistency is that nothing is constant, if that makes any sense. The strive for reaching the "perfect evolvement" never ceases for it depends on so many outside factors that it can happen at any time. "In there new homes they will be exposed to new conditions, and will frequently undergo further modifications and improvement; and thus they will become still further victorious, and will produce groups of modified descendants" (350). Still Darwin points out that evolution still takes place towards better improved offspring and genes.
ReplyDeleteHumans into this topic of survival of the fittest and taking out the ones with the bad genes is a topic that delves into some uncertain areas. Like one bad cow in a large cattle farm will probably be taken care of so that the meat is not contaminated, this is not the same with humans. We simply do not do this with humans, but I assume taking our problems to the medicinal department and stopping anything major supposedly being inherited by the next generation is somewhat the same concept. Though there are still other big diseases in our world that plagues many humans and causes harm among its possessors. Those people will be part of this natural selection. We might not see the modification, but they are possibly "chosen" out to struggle for their existence (meaning passing on their genes). Eric raises an excellent point here and can be really further discussed in so much more depth.
It is clear that Darwin, with the exception of his discussion eyes, avoids bringing humans into his discussion of natural selection. By including humans in the discussion we run into problems with social Darwinism. In response to Evan's question regarding the extent to which humans are evolving, I think that humans are evolving in ways that do not include genetics. In my biology class last year, we talked about cultural evolution. Cultural evolution occurs much quicker than genetic evolution and is a result of the ability to use tools. As new tools become available, the way that humans interact with their environment changes as a result.
ReplyDeleteEmily- What you say about the "phenomenon only applies to people of means" really got me thinking. You say, "These days, if you have money, you no longer have to be the fastest runner, the strongest hunter, or the most temperature-resistant." This all has to do with environment. Darwin says environment is crucial in the process of natural selection. Humans live in all sorts of different environments. I could probably take any human being and stick them out in the wilderness and forget about how much money they have—natural selection would run its due course. But this artificial environment humans have created, has allowed for people who are less fit to survive. We wear clothes so we don't have to evolve and grow hair, we go to the Grocery store so that we don't have to hunt and gather our own food, etc. Remove the artificial environment (clothes, stores, houses, etc.) and we are stripped bare. For now, I think the argument that the wealthiest avoid naturally selection is by some means true. Yes, people of wealth still die, but they have much greater means to ensure their health and the health of their children as currency is what provides for the environment that is so crucial to our survival today.
ReplyDeleteI think that human evolution is developing in a different manner than defined by Darwin's rational explanation of the struggle for existence. We have developed enough crutches and workarounds to mitigate most problems faced by humanity. This isn't to say we are free from danger, as mentioned by Emily there are still many conditions yet to be solved. For example cancer and AIDS represent pressing problems within our own genetic code. I see ourselves as being able to both accelerate and mitigate the need for evolution. As soon as one individual who is identified with a certain resistance we can analyze and break it down and possibly engineer a solution or treatment from that. Meaning while the entire population isn't developing and replacing the previous species, that process is becoming less and less necessary in terms of Darwin's original definition of evolution. The entire species is instead being improved by treatments and is mitigating the need to evolve out of the struggle for existence. This isn't to say evolution isn't occurring or rather that it isn't important. But as a species we have found a way to "evolve" without actually developing as a species as darwin defined evolution.
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