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Author Topic:   why DID we evolve into humans?
tomwillrep
Inactive Member


Message 1 of 231 (43556)
06-21-2003 9:32 PM


i was just thinking - why did we evolve into the state we are in now-
i've read topics saying that we no longer need to evolve as we just "invent" or make what we need - such as to fly we created planes, to help with bad eye-sight we made glasses, to combat disease we invented cures.
why did we need to evolve into humans (if you believe that we did). what do apes NOT have that they needed to become humans - and if it is they needed ability to talk - why did they just not have voice boxes as they are now - if it is because they wanted to walk upright - why?!
why did we even evolve into apes from the creatures we "were" before - if we originally were underwater creatures why was there earth and why did we leave the water, also why have we not stayed consistent in being able to do things that past "ancestors" were able to do - from apes to the first origin?!
views on this would be appreciated

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IrishRockhound
Member (Idle past 4436 days)
Posts: 569
From: Ireland
Joined: 05-19-2003


Message 2 of 231 (43560)
06-21-2003 11:42 PM
Reply to: Message 1 by tomwillrep
06-21-2003 9:32 PM


It's all down to natural selection. Humans just happen to have a very advantageous form, like being able to walk and run upright, having very dextrous hands, being intelligent etc.
We're human shaped because the world likes us that way
The Rock Hound

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DBlevins
Member (Idle past 3776 days)
Posts: 652
From: Puyallup, WA.
Joined: 02-04-2003


Message 3 of 231 (43568)
06-22-2003 12:22 AM
Reply to: Message 1 by tomwillrep
06-21-2003 9:32 PM


Hello tomwillrep,
I think the problem you're confronting is in describing evolution as being "motivated" toward some goal. Simplistically stated, we evolved into what we are by a process of natural selection. There wasn't a stated goal to where we would be headed. It just happened that those traits that we carried either helped us adapt to our environment or were selected out. Our path is just one of a multitude that happened to survive. There was a time when there were different forms of bipedal hominids, robust plant eating forms with thick jaws and molars for crushing plants and nuts, smaller types which were more generalized, etc. Our path was one toward a more generalized, bipedal, large brained form.
The apes that are alive now specialized along a different path than ours, they remained arboreal. (as far as I know they didn't evolve from non-arboreal bipeds). The point i guess i'm trying to make, poorly that is, is that there is no "directive force" or motivating force" for evolution. It just uses what we have or discards it, over periods of time depending on what "works". As far as voice boxes are concerned, apes don't need them to survive. They are successful (so far) without them. somewhere along our lne of descent we evolved voice boxes which we found a need for. Some form of communication, I'd almost argue, is a necessary componant of survival. We happened to use our voice box as one way of communication.
Who knows if our experiment of form will survive? It may come to be that large brained culturally advanced bipeds will be selected out, through their own devices (war, overgrazing ) or by some other agent (disease, catastrophic event/s, extreme environmental change).
I'm not sure if I answered your question, but it did seem there were some mistaken ideas about evolution in your question.

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tomwillrep
Inactive Member


Message 4 of 231 (43605)
06-22-2003 9:45 AM


"I'm not sure if I answered your question, but it did seem there were some mistaken ideas about evolution in your question."
care to elaborate which they were and i'll explain what i meant by them? thanks
my understanding is that there are 2 forms of evolution - one is natural selection - one is actually changing form or "producing" from nothing and from what we don't know-something that we need -for example- if we didn't know what voice boxes were - why did we want one - animals communicate perfectly with eachother-why did we need voice boxes?
when i ask why we evolved into humans- the answer that it is from natural selection cannot be true - as that would suggest that humans were already alive at the time - humans being stronger and able to survive in that environment and so they survived.
darwins natural selection states that there were species, all different kinds in that species - for example giraffes (though i think this theory was put forward by someone else as well), we had long necked and short necked ones. the long necked ones survived.
to say humans came from natural selection cannot be true - as they would have needed to be alongside other animals and needed to be the only species to survive in that environment that they were in.
if humans "evolved" that suggests that apes/chimps or whatever animal it is nowadays that we came from, changed its features and somehow produced features that it knew nothing of and was not in need of (otherwise monkeys would not be around today). why did the monkeys become humans if they are perfectly capable of living as they are?
also - if we so wanted to do so many things that we can't in our natural state- why did we not just evolve them-such as wings to fly, gills to stay under water longer.
why was it that we only invented contraptions to do these things within the last century or 2?!

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Asgara
Member (Idle past 2303 days)
Posts: 1783
From: Wisconsin, USA
Joined: 05-10-2003


Message 5 of 231 (43685)
06-22-2003 9:17 PM
Reply to: Message 4 by tomwillrep
06-22-2003 9:45 AM


evolution
Tom,
I am not a scientist but even I can see the fallacies in your post...
my understanding is that there are 2 forms of evolution - one is natural selection - one is actually changing form or "producing" from nothing and from what we don't know-something that we need -for example- if we didn't know what voice boxes were - why did we want one - animals communicate perfectly with eachother-why did we need voice boxes?
There is only one "form" of evolution. Natural selection working on random mutations to change a population over time. Random mutations do not "know what we need". A mutation happens that makes the individual with the mutation better able to survive and reproduce than individuals without the mutation. Chances are that the individuals with the better chance at survival will leave more offspring than others less able to survive. Many of these offspring will inherit the mutation and be able to pass it on to their offspring. All these individuals with the mutation are better adapted to their invironment, better able to survive to reproduce.
There was no one individual who sat down one day and thought, "gee, I'd like to be able to walk upright so I am better able to see danger coming." But...the ones who had mutations that enabled them to walk in a more upright posture were better able to survive because they could see danger coming faster than their neighbors who didn't have these mutations. Now, in this population, filled with individuals who had the mutations AND individuals who didn't have the mutations...which ones do you think will be better able to survive? If more individuals without the mutations are getting caught as dinner for a preditor than are individuals with the mutation....which group do you think will have more offspring?
Evolution does not have a specific end product in mind, but an end product will occur...one that is just good enough to survive better than a previous one.
also - if we so wanted to do so many things that we can't in our natural state- why did we not just evolve them-such as wings to fly, gills to stay under water longer.
why was it that we only invented contraptions to do these things within the last century or 2?!
IF a mutation occurred that inabled us to stay underwater longer than others...and IF there was a benefit to us to do so (for example, we were subject to a preditor that couldn't swim but could easily catch us on land) More of us with the mutation would survive then those of us without it (the ones who couldn't stay underwater as long would be the first ones eaten by this preditor) Those of us WITH the mutation would survive to pass on our genes (including the mutations)
In our (humans) past there was no survival benefit to being able to fly (or no mutations happened that would enable it in the first place), so we did not evolve into a flying creature. We DID evolve larger more intelligent brains, this is our survival adaptation...we use this adaptation to invent things to help us do things like fly or stay underwater longer.
Have you ever played a game of Yahtzee? The dice fall in a random order (random mutations) and you (natural selection) chose which ones are kept for the next generation (roll of the dice). Before you ever roll the dice, you don't say that I am going to get all sixes...you take what is rolled and keep the dice that enable you to get "something" that is helpful, whether it is three fours, or a straight or whatever you are able to get with the dice that you throw.
Hopefully one of the more scientific types can correct any mistakes I have made here. I am just attempting to explain it in the simplist way possible.
------------------
Asgara
"An unexamined life is not worth living" Socrates via Plato

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Replies to this message:
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Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 6 of 231 (43741)
06-23-2003 9:44 AM
Reply to: Message 1 by tomwillrep
06-21-2003 9:32 PM


Random mutation & envirnmental pressure.

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contracycle
Inactive Member


Message 7 of 231 (44103)
06-25-2003 7:05 AM


quote:
why did we need to evolve into humans (if you believe that we did). what do apes NOT have that they needed to become humans - and if it is they needed ability to talk - why did they just not have voice boxes as they are now - if it is because they wanted to walk upright - why?!
Thought I'd pick up on this. As others have pointed out, there is no "intent" driving evolution, it is merely random accident, more or less.
Humans are a "plains ape". There are apes that live in forests and jungles etc; we just happened to come from a line specialised for savannahs, probably (which coincides nicely with the Out Of Africa hypothesis). It was a good and useful developement; putting the sight organs as high as possible extends the range of vision and alertness. Vertical walking is quite efficient over long distances, and quite useful over short distances becuase we can shift our balance point. [ A human can beat a horse over 100 meters, if its broken into two 50m stretches; the horse loses time taking the corner]
Communication is just plain Useful among any socially structire animal. Gelada baboons exchnage a hell of a lot of vocalisation, and show some other interesting features; becuase they spend a lot of time parked on their butts pulling up grass, sexual displays appear to have moved to the chest, in a manner analogous especially with human females.
The cetaceans, of course, are famous for large volumes of communications. I heard some orcas in a fjord in Norway last year by hydrophone - the sheer volume of data they are exchanging is absolutely staggering, there is a non-stop layer of continual chatter.
Communication is evolutionarily beneficial; it is independantly "invented" by many organisms. Our upright stance is odd, but we can understand the evolutionary benefits. And we know that there were benefits, becuase humans come 3rd on the European carnivore guild, after cave bears and lions (in that order) and before wolves. Thats not bad going considering we have so few natural weapons.

Dr_Tazimus_maximus
Member (Idle past 3217 days)
Posts: 402
From: Gaithersburg, MD, USA
Joined: 03-19-2002


Message 8 of 231 (44120)
06-25-2003 9:01 AM
Reply to: Message 4 by tomwillrep
06-22-2003 9:45 AM


You have got to be kidding me!!
I have not seen some of this dren in a while.
quote:
when i ask why we evolved into humans- the answer that it is from natural selection cannot be true - as that would suggest that humans were already alive at the time - humans being stronger and able to survive in that environment and so they survived.
This is absolute bull. What it would mean is that there was a species which had some characteristics that are part of modern humans, and some characteristics which are not found in modern humans (modern humans will also possess certian characteristics not found in the earlier species). The same for the earlier species that humans came from, et. That is why it is called evolution, the system (hominid in this case) changes.
quote:
to say humans came from natural selection cannot be true - as they would have needed to be alongside other animals and needed to be the only species to survive in that environment that they were in.
Also untrue, I think that here you are confusing animals that live in a certian environment with animals which occupy a certian niche within that environment. And guess what, there were multiple early hominid species (I am including later australeopithicines with early homo in this) of which only one group had survivors, US. Hey, that is just what you said would happen if humans evolved by natural selection, guess that you agree with our camp now .
quote:
if humans "evolved" that suggests that apes/chimps or whatever animal it is nowadays that we came from, changed its features and somehow produced features that it knew nothing of and was not in need of (otherwise monkeys would not be around today). why did the monkeys become humans if they are perfectly capable of living as they are?
Actually we are more closely related to apes than monkeys (a chimp is a ape, or primate as most prefer). And the species split, some became "monkeys, ie the great apes; and some became hominids. They split into different niches: demes and memes.
quote:
also - if we so wanted to do so many things that we can't in our natural state- why did we not just evolve them-such as wings to fly, gills to stay under water longer.
what exactly is it about the largely random nature of mutations that you do not understand. You sound like a Lamarckian, but then you know that they are also evolutionists, don't you?
------------------
"Chance favors the prepared mind." L. Pasteur
Taz

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DC85
Member (Idle past 380 days)
Posts: 876
From: Richmond, Virginia USA
Joined: 05-06-2003


Message 9 of 231 (45018)
07-04-2003 1:01 AM


this is the simplaiest way to Put it with all of Evolution. it happened so the creature could survive. there is no Real reason Humans are Humans its just as Simple as that . We didn't set out to Become humans it just happened ok
C=cause E=effect
(C)we needed a way to Avoid being Hunted By more dangerous animals.
(E) so we Started living in social groups(happened before primates)
(C) we Need to Eat better food out of Danger
(E) we evolved the ability to use tools (chimps do this)
though it happend there is no Goal Evolution doesn't work like that.
we just Happened it as simple as that Chance is all it was. we need to survive so we Evolved thats all.
[This message has been edited by DC85, 07-04-2003]

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NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 10 of 231 (45081)
07-04-2003 12:54 PM
Reply to: Message 9 by DC85
07-04-2003 1:01 AM


No, DC that's not the way I would describe it.
The need does NOT cause the change.
Our ancestors were there, faced with a number of changing situations. Some had small differences that were helpful some didn't. Some lived, some died. The conditions and the differences caused the living and dieing but did NOT cause the changes in them.

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DC85
Member (Idle past 380 days)
Posts: 876
From: Richmond, Virginia USA
Joined: 05-06-2003


Message 11 of 231 (45121)
07-05-2003 1:03 AM


well I have no doubt Evolution takes place however I can't see it ALL as Random Mutations......... Animals need to adapt so they evolve to the change in the enveronment. I can't Believe that the Human Brain just was all Random mutations
However I will agree Random Mutations take place for Example a Place that never or barely changes animal species still Evolve. Dinosaurs are the best Example of this. I don't think it can be all random........

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NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 12 of 231 (45124)
07-05-2003 1:38 AM
Reply to: Message 11 by DC85
07-05-2003 1:03 AM


There is no reason to think it is anything but selected mutations.
As for brains, look under the book nook for my entry on Nature via Nurture. It may not be so hard to produce mutations to increase brain size as we might think.

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Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 13 of 231 (45735)
07-11-2003 7:04 AM
Reply to: Message 11 by DC85
07-05-2003 1:03 AM


It depends largely what you mean by 'random mutation'.
Evolution isn't random ... it is governed by natural
processes which involve selection.
I can see any extant trait as an evolved one. Intelligence
(if you wish to call it that) is just a trait like any other
it has conferred advantages which lead to higher survival
rates ... and thus subsequent generations with higher and
higher frequencies of the trait.

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MarkAustin
Member (Idle past 3815 days)
Posts: 122
From: London., UK
Joined: 05-23-2003


Message 14 of 231 (50677)
08-15-2003 5:33 PM
Reply to: Message 5 by Asgara
06-22-2003 9:17 PM


Re: evolution
quote:
There is only one "form" of evolution. Natural selection working on random mutations to change a population over time.
Not strictly true. There is another form of evolution. Sexual Selection. It is almost identical to Natural Selection but instead of selection by improved survivability, it involves selection by improved attraction to the opposite sex, and thus descendants.
There is a good Sexual Selection explanation of humanities large brain:
When man split off from Austalopithecus, and became a hunter, bands became larger, thus enhanced communication was needed (Chimps enhance group solidarity by mutual grooming, Man by talking - more efficient as it allows bigger groups), thus the most succesful communicator in a group would attract higher status, thus a better chance of leaving descendants.
[This message has been edited by MarkAustin, 08-15-2003]

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Asgara
Member (Idle past 2303 days)
Posts: 1783
From: Wisconsin, USA
Joined: 05-10-2003


Message 15 of 231 (50682)
08-15-2003 6:09 PM
Reply to: Message 14 by MarkAustin
08-15-2003 5:33 PM


Re: evolution
Hi MarkA.
I don't believe that natural or sexual selection = evolution. Both are simply processes whereby evolution takes place. These processes work on genetic variations to produce a change in a population over time. This change in the frequency of alleles in the population is evolution. It would seem to me that sexual selection is just a variation of natural selection allowing the individual to pass on more of its genes.
------------------
Asgara
"An unexamined life is not worth living" Socrates via Plato

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