. then, how do you explain this changement, all changements should have a reason, so, why does this happen to the human body, and the humans anyway.
Any specific change or change in general? What happens is that human beings are all slightly different and those differences tend to be passed on to our children. Reproduction is affected by these traits, since some traits lead to greater reproductive success. Not everyone reproduces the same number of times, and some people do not reproduce. So, the frequency of any particular trait in the population changes over time.
. so, you said small changes, how do you know that those small changes are adaptation, and evolution is not gerally a game or something that always run, evoluion is adaptation, for example, if you find a hard worker, work alot with his hands, you'll find he's hands are bigger than a person who works in a desk or an office, i can see that by self, and other changes of adaptation, like we can stay in a tempeture of even 32°C without being so tired, while we take a european, or someone who always lived in cold weather, didnt used to heat, and come into 32°C he will get tired faster. keeping blamin evolution, is so childish, to someone who can't find a reason so he say evolution. i asked you to say how evolution happen, why? and how? how does those changement happends, and for what reason? you didnt answer that, you just said a small definition.
What you are suggesting is called Lamarckian evolution, (the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring) and it has largely (but not completely) been discredited. My definition of evolution also explains why it happens. The less fit tend to reproduce less and the more fit (in the context of a particular environment) tend to reproduce more, and so the genes for the attributes that create fitness increase in the population over time. That is how living things adapt to their environments. It's not that we say evolution because we can't find a reason, it's that evolution can explain so much.
I agree that evolution can explain so much, but in some studies it seems as if they "try" to fit it with evolution. Also the Lamarckian evolution interests me.. You've mentioned that it hasn't been completely discredited.Can you mention any reports that approves it?
Of course they try. If there were a case where evolution could not explain some trait, it would be scientifically important. You can look at the wikipedia entry, they say that some environmental factors like stress can cause certain aquired traits to be heritable, but Neo-Darwinism explains so much that Lamarckian evolution will supplement it at best, not replace it.
. ok, hmmm, no i wan't choose a behavior, because it's a sicologic thing, and depends on the society, not evolution, duuh. why don't you start?
"YAAEK!" indeed. Those two are grotesquely twerpish. This is better Please Register or Log in to view the hidden image! ~String
Sorry, the reception was a little off. That was all I could really find before I felt like YAAEKING all over my Please Register or Log in to view the hidden image!
Depression maintains the fitness of the gene pool by providing incentive to desist in behavior that results in a severe negative life event.
Negative life effect like going to work? or like losing a job through no fault of ones own. People kill themselves for many reasons, only some are from negative behaviours (alcohol, drugs, divorce etc)
OK, you are confusing (deliberatley or otherwise) suicide with depression. My challenge to you was suicide. You are answering the question on depression. (you would make a good politicianPlease Register or Log in to view the hidden image!) Your link quotes depression as an "important risk factor for suicide", but far from the only one. Suicide is; http://en.wikipedia.org/wiki/Suicide Your answer again please sir..
If you are depressed, you aren't fit for life, therefore it would benefit those related to you to remove your set of genes from the gene pool. Evolution would favor the trait for depressed or hopeless individuals or people in a hopeless situation to commit suicide.
I know we are veering further off topic here, but I still say suicide an depression are not synonymous, and you are talking about depression. I found this; “You may retort that to contemplate suicide is itself proof of clinical depression: that nobody of sound mind kills himself. This is the old Catch-22 get-out by which the Church has rationalised giving a proper Christian burial to suicide victims, and countless grieving relatives have comforted themselves that a death was not, in the fullest sense, self-inflicted because their loved one was not wholly capable of knowing what he was doing. In many cases that may be true, but not in all. Despair is not always unreasonable. Here are three good reasons for suicide: three circumstances in which a clear-headed decision may be taken in a state of mind which is bleak but not unbalanced. I do not say that any of these three reasons would usually justify taking one’s own life: only that they might. They are infirmity, self-sacrifice and shame.” Taken from here ; http://www.timesonline.co.uk/tol/comment/columnists/matthew_parris/article393107.ece
I am looking for plausible genetic reasons. As humans with a complex culture, we cannot of course attribute everything to genetics, but the phenomenon of suicide following depression seems to be universal. We can also see self-destructive behavior in animals when confined, and modern humans are often confined in urban or overcrowded areas, or confined by the social structure. We know that stress and poverty can cause people to take more risks, to have children earlier and be more violent. Their genes are telling them that it's a risky time and they should therefore reproduce more in order to ensure survival, as the death rate for children would be higher. It could be that animals simply lack the tools or intelligence to kill themselves, even when they feel like it. Another mechanism might be infirmity, killing yourself would leave more food available for your offspring, and so it could be a natural reaction to an impossible situation.
