macroevolution has effectively stopped in humans
remember, evolution is where the weak die and the only those that live to copulate further their genes. changes in specific animals don't cause evolution... eg, you can't cut your thumb off and get your kids thumbless.
there will be spurts as those who are superior will tend to get together etc... but on balance, the weak will dilute the gene pool. we will never branch off into another species or become superior in our own, if we don't have the weaker among us die off.
and in every other sense that we might be considered 'evolving' it is minor.
PRO has claimed that Homo sapiens will not evolve into a different species, AND that we will not be significantly changed as a result of evolution. As PRO holds the burden to demonstrate these assertions, I will begin with a general overview of how I think she is mistaken, and provide a hypothetical situation where both of those assertions would be incorrect. I will then wait for PRO to provide her evidence so that I may address it directly.
Speciation is the formation of a new species from an existing species . It is accepted science that modern Homo sapiens evolved from a different species in a process of evolution that began about 200,000 years ago , likely from the species Homo heidelbergensis . Also, it is well understood that the human genome is still evolving . I therefore challenge PRO to demonstrate how the continued evolution of humans will NOT result in a speciation event.
There have already been significant changes to the human phenotype, although not all of them obvious to the casual observer. One good example is lactose tolerance. There is evidence that as recently as 5000 BCE most adult humans did not produce sufficient quantities of the lactase enzyme to drink milk without gastrointestinal discomfort. However, most non-Asian adults are now able to do so as they have evolved the ability to continue produce in the lactase enzyme into adulthood . This has led to numerous social, cultural, and nutritional changes in how we humans carry out our everyday lives. Since significant changes to the human genome are already well known and documented, I challenge PRO to demonstrate her claim that there will no longer be any significant alterations to humans.
As promised, I will not present a hypothetical situation which I believe will demonstrate beyond any reasonable doubt that it is quite possible for Homo sapiens to further (macro) evolve. At least two countries (Russia  and Japan ) have plans to put permanent bases on the moon. There are two things that push evolution along: isolation, and selection pressures. In this case, one selection pressure is obvious: the relatively low gravity of the moon . The isolation would be a matter of the high cost of transient to and from the moon . As a result, there would be little opportunity for the transfer of genes between those who live on the moon and those who live on Earth. To compound the problem of isolation, there is the likelihood that a long term moon colony would develop its own culture , which would make it unlikely that any casual encounter between the Earth and the moon would result in a swap of genetic material. Therefore, the environmental and social pressures along with isolation would result in a divergent evolutionary path, after which, speciation is only a matter of time .
PRO has asserted both that humans will not evolve into a different species, and that humans will not be “significantly altered” as a result of evolution. I have demonstrated both that humans did evolve from a separate species, and that we have already undergone significant alterations as a result of evolution. I challenge PRO to demonstrate why these patterns will stop. I have also provided a hypothetical situation, which I do not think is far fetched at all, that outlines one possible way humans could undergo speciation. I look forward to PRO’s comments in the Round 2.
con says humans have developed lactose digestion abitilty. that may be, but i wouldn't call it sigificant. we might have to just agree to disagree a bout what is significant. but we dont see anatomical changes or any other "really" major change. plus, the lactose change probably happened well in the past. nowadays the inability to ingest lactose won't cause you to die and your relatives to evolve, as it happened back then. so my resolution is still true, that it "has" stopped as of teh present time.
con presents his moon hypothetical. notice though, i didn't say evvolution has stopped, or will never occur again. i said it has effectively stopped. we do not see anything like outer space colonies occurring anytime soon so my resolution stands. plus even if they did have one on the moon or even mars, there would be new people joining the colony and adding regugular old human genes to the mix. it wouldn't really be that isolated, preventing significant evolution.
Thank you PRO for your comments this round. I am going to address your points out of order, because I would like to go through them in order of importance.
What Are We Debating?
In PRO’s final paragraph this round, she wrote, “i didn't say evvolution [sic] has stopped, or will never occur again." This may be the case, but PRO did claim that speciation will not happen again; the very first sentence of this debate begins, “we won't be developing into another species…” This is what my moon colony hypothetical was about. There are numerous other ways populations could be isolated, such as a Mars colony, which PRO suggested. My point wasn't about the specifics of such a colony; it was simply that isolation will lead to divergent paths of ecolution, which, over time, almost guarantee a speciation event.
PRO has attacked my point about the evolution of lactose tolerance as not being significant. This is absurd. The ability to digest lactose makes people more able to survive famines, and has aided the spread of civilization . It has even been hypothesized as one of the reasons for the fall of the Byzantine Empire .
The fact is that we as humans are still evolving . I chose to discuss the lactose example because I was familiar with it. The evolution of lactose tolerance occurred within the past 10,000 years , which is a blink of an eye in geologic or evolutionary time, so there can be no doubt that we are still evolving. Of course, PRO has complained that it is not significant, and notes that we don’t see any “anatomical changes." If PRO thinks that the fact that we haven't grown additional limbs means that we aren't evolving, she is mistake about how evolution works.
We finally get to the transposons. The reason I used that source is because it is something I had read somewhat recently that showed how these retro-transposons are the result of the evolutionary success of specific “selfish” genes . The point is simply that we are still evolving. I really didn’t think I needed to source that point; the fact that we are still evolving is beyond dispute, but I try to make it a point to source everything.
PRO seems to have no problem with the fact that we are still evolving. She wrote, “it just looks like there might be minor genetic deviances [sic] still occurring, which i never contested." Genetic change in a population over time is evolution . Since PRO is not contesting that we continue to evolve, she needs to provide evidence for why we cannot expect a speciation even in humanity's future.
A Wrap Up
The thing I want to hammer home here is that PRO’s main point, that humans will not evolve into a new species, has not been supported with evidence. At this point it remains a bald assertion. Her secondary point, that we will not be “significantly altered” due to evolution, similarly remains unsupported. I look forward to PRO’s comments in the final round.
we have to agree to disagree about whether lactose tolerance is signifant or not. i say it's not. but even if it was, it doesn't change that my resoution is present tense, not to include 10000 years ago when people still died much more rampant from malnutrition. con just ignores rebutting that part, that i was speaking in the resolution in the present tense.
Thank you PRO for your comments.
First of all, PRO is complaining that I am latching on to her “sloppy language” in order to change the meaning of the debate. However, the verbiage I used is the very first line of PRO’s first round arguments. This is the part of the debate traditionally used to clarify the instigator’s position, as the title of the debate is not always the resolution. Also, PRO did not object to the way I interpreted her resolution in her second round comments; it is only now that we get to the last round is she complaining. Whether or not the statement made by PRO is simply “sloppy language” is moot; she stated it, and I made it clear in the first round that I would be arguing against it.
PRO talks about agreeing to disagree regarding the significance of lactose tolerance, but I have demonstrated that it was significant, and the fact that it happened millennia ago is irrelevant, as the humans of that time were more or less genetically identical to the humans of today.
In this debate, I demonstrated that humans are still evolving, and that significant changes have happened recently. I have also provided a hypothetical situation in which the conditions to speciate would be present. In contrast, PRO has not provided a single shred of evidence in support of her resolution that humans will not experience a speciation event.
A Final Wrap Up
I would like to thank PRO for instigating this debate; I do enjoy discussing evolution. As usual, I have found the discussion to be intellectually stimulating and entertaining. To the voting!!!
|Agreed with before the debate:||-||-||0 points|
|Agreed with after the debate:||-||-||0 points|
|Who had better conduct:||-||-||1 point|
|Had better spelling and grammar:||-||-||1 point|
|Made more convincing arguments:||-||-||3 points|
|Used the most reliable sources:||-||-||2 points|
|Total points awarded:||0||3|