November 24, 2011 at 12:38 pm #15731
Can human evolve?
If yes, Because human contribute environment natural selection is not possible. How can it occur?
November 24, 2011 at 3:22 pm #108378ChesneMDParticipant
Natural selection takes place regardless of human interaction. But humans can manipulate it to a degree that maldaptations are irrelevant, depending on which one it is. For instance, if your eyesight is incredibly poor, we can stick glasses on you to help ensure survival. But it does occur, just in a more refined way for humans. Now, whether or not we are actually evolving, meaning that we are changing toward something, many anthropologists debate it. Some feel that we still are, but others feel as if we are stagnant. And of course the reason for that is we are unaffected by the environment for the most part. We have houses, medicine, etc.
I am on the side who suggests we are stagnant. That being said, I think we can add in, if we don’t already, any factors we’ve created ourselves to be part of our environment and act as a replacement for things we’ve lost (if you were to treat it like a formula).
November 24, 2011 at 3:49 pm #108382
Finally,what’s your point? Yes or No?
November 24, 2011 at 8:30 pm #108383CatParticipant
Same old argument…
Evolution is change over time! It does NOT have a goal. Natural selection is the force that imposes limitations on diversity. Today, humans (for most part) are not under natural selection force. This leads to diversity. Diversification IS change over time and, therefore, evolution…
November 25, 2011 at 12:35 am #108384ChesneMDParticipant
No one said anything about a goal, lol. The only remotely related thing was when I said "toward something", as in something actually being different. But in no way implied a goal.
And you reiterated what I said. I don’t know if that was your intent or not.
November 25, 2011 at 3:27 am #108386quote Cat:
First evolution happens by other means than natural selection like genetic drift, or founding effect/separation of population, which will constrain diversity, although I would say that those do not affect humans.
Second, I a m pretty sure we are evolving. Sexual and cultural selection probably affects us (with such factors as skin color) to some extent. And plenty of environmental factors are affecting our health and reproduction whether we realize it or not. Diseases like AIDS, the use of cows milk in diet to cite 2 examples, and many other things can and do affect us. They change us, maybe not a lot, and certainly less and not in the ways than the guy in the other thread think it does, but we evolve, randomly, to somewhere else given enough time
November 25, 2011 at 5:48 am #108388
I’m really appreciate it sir canolon. your response was quite well.
November 25, 2011 at 7:15 am #108392quote Cat:
If it was, there would be only one species of bacteria and nothing more.
November 25, 2011 at 7:42 am #108394
November 25, 2011 at 3:22 pm #108414quote JackBean:
No, Cat is right!
Diversity is created freely and randomly by mutations, natural selections, and a few other things will select which mutations will go on the next generation thereby limiting the diversity to what is not only viable, but fit.
December 6, 2011 at 7:44 pm #108600CatParticipant
I am curious, Canalon. What are “few other things” you mentioned? I cannot think of anything that does not fall into natural selection category…
December 7, 2011 at 3:25 am #108602
I meant things like genetic drift and founding efect. This is not Natural selection per se as they are not a selective event, just random event that will limit diversity. But of litle interest for the sake of the argument that JackBean was making.
December 7, 2011 at 3:44 am #108606joe777Participant
Yeah, Cat and canalon have it spot on. We’re evolving, but there is less selection involved (not none, diseases and lack of resources still affect some parts of the world to a large extent.) and hence we are diversifying.
February 1, 2012 at 8:04 am #109353
i want to know other thing about this topic
How much is the resolution of the phylogenetic?
can we know the time the chinese and westerner separation 😀
February 2, 2012 at 2:18 am #109370quote Cat:
i have a idea: i want to do some experiment of human evaluation with bioinformation on my computer. i want to select one chromosome to do the experiment. do you have some advice for me? i hope i can get the answer of the divergence time between the chinese and westerners.
February 2, 2012 at 8:00 am #109375
what exactly do you want to do?
February 2, 2012 at 8:07 am #109376quote JackBean:
could u give me some reference about human evaluation. i want to know the relationship of the human species, especially about chinese and westerners
February 3, 2012 at 12:02 am #109404quote jmagicking:
Chinese and Westerners are interbreeding (as with most of the human population), and are thus part of the same gene pool. I think this makes them unlikely to diverge/speciate unless the current trend of globalization reverses, and remains that way for many more generations.
Keep in mind that we did not speciate over the 50-60,000 years since the populations originally split apart – and in relation to our biological mechanisms, the differences that have accumulated so far are tiny. If you want to make an estimate assuming no interbreeding, you then need to know the strength of natural selection on each population relative to the other – which is not yet agreed upon (and it’s the topic of this thread, after all!) While evolution can certainly act on very short timescales, it requires massive selective forces to do that.
February 16, 2012 at 9:27 am #109670
3q for AstraSequi’s advice, i had not conside the interbreeding before.
so, it is difficult to estimate the diverge, but you said 50-60,000 ago we have split apart, how do you know that?
why i want to know this thing, because i think our genes( biological mechanisms) lead to our culture differece, not the environment.
February 19, 2012 at 1:32 am #109736quote jmagicking:
It is a rough estimate based on the initial spread of humans from Africa – the last time the two populations had a common ancestor was when we reached the Middle East. For example, see http://en.wikipedia.org/wiki/Early_human_migrations and http://en.wikipedia.org/wiki/Recent_Afr … ern_humans.
Actually, reading more carefully, I think I might have been too conservative – it seems like the split might have been much earlier than that. I don’t think the answer is known with great certainty (though it seems that around 50,000 years is a lower limit, since there are many human artifacts found elsewhere by then).quote :
I don’t know enough to comment on that. However, it’s definitely something that you would need evidence for, not something you could simply calculate. For example, you could start with looking at children from one population but adopted into another (I’m sure that many such studies have already been done). It’s also very hard to get proper, ethical controls for human studies, so you might find information pointing in all directions on some topics.
February 27, 2012 at 3:07 am #109890
today, i find a simple method that prove my viewpoint( my culture is decised by our genes ) is wrong. because culture can be communication, we can learn each other.
so, this is another questions about the topic, how to define the Homo sapiens from the biology, whether have a genetic characteristics.
February 27, 2012 at 5:38 am #109893quote AstraSequi:
i have a question is why we select y chromosome or mtdna to analysis human evaluation
March 1, 2012 at 7:24 am #109948quote jmagicking:
We define species like humans based on reproductive compatibility – if you can produce fertile offspring, you are part of the same species.
Of course, the human genome is different from the genome of any other organism, so you could definitely use genetic characteristics to identify it. For example, no other species has exactly the same collection of FOX genes as humans, or exactly the same collection of CYP genes, etc. However, these do not define the species, because if we found an animal that did have the same sets of genes, that would not make it the same species – only reproductive compatibility allows that.quote :
Generally because the Y chromosome is only passed down from father to son, and mtDNA is only passed down from mother to daughter. I don’t know enough to talk about why this is useful though.
March 2, 2012 at 3:35 am #109952quote :
as you say, so y chromosome and mtdna is more conservitavie than genetic material. euchromosome obey "Law of linkage and crossing over ", so if a chinese man marry a european womom, the euchromosomes have more mutations than y chromosome and mtdna. that is my understanding
March 3, 2012 at 4:07 pm #109970animartcoParticipant
I think as a species we are evolving faster than any other species. (of similar size) This is because we are changing our environment so fast. Physically we are loosing the ability to cope with the natural world. This shows in our reaction to cold for instance- the loss of ability to manufacture brown fat, and also in the great upsurge of allergic reactions. There must be many more subtle changes that haven’t been documented because they are occuring so fast.
The point is that evolution is not necessarily ‘good’. If it is good the species survives if it isn’t the species dies out.
- You must be logged in to reply to this topic.