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llanitedave
Humble Megalomaniac
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Sentient, Intelligent, or Human? new [Re: Otto Piechowski]
      #5944146 - 06/28/13 01:58 AM

The mammal genome has the vitamin C gene, but in higher primates, the gene is broken.

The Genetics of Vitamin C Loss in Vertebrates


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Pess
(Title)
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Reged: 09/12/07

Loc: Toledo, Ohio
Re: Sentient, Intelligent, or Human? new [Re: llanitedave]
      #5944633 - 06/28/13 11:31 AM

Quote:

Quote:

evolution is caused by the environment




As EJN said, not necessarily. Evolution can occur in the absence of environmental change, via genetic drift. Further, even when a species is forced to adapt to a changing environment, it's not always predictable what direction that adaptation will take. For example, consider a mammal in a tropical environment that grows colder. To adapt to the cold, there are several solutions to the problem available. The population can grow longer warmer fur. It can grow fatter for insulation. It can grow physically larger. It can increase its metabolism to generate more body heat.

None of these potential solutions is exclusive to the others, and all of them are going to carry incidental consequences -- which adds to the unpredictability of the future.

So what IS the relationship between the environment and evolution? Exactly how do you define *cause* under such conditions? It's there, but it's not amenable to glib or simple statements.




I'm not sure I get this line of thought.

If you have a religiously static environment you still get evolution. That environment will select what gene expressions work best to date, not necessarily what work best out of all possible combinations.

So despite a never changing environment some mutations will occur at random that work 'better' than what has worked for eons and thus the new characteristic will allow that species to out compete its brethren which may have dominated for eons.

Changing environmental conditions only select for genes that may have previously had no particular competitive value before the change or may have been detrimental before the change.

A prime example comes to mind. Moths in an industrialized city were light colored and almost invisible to see against the light colored bark of trees and thus hard for predators to see. Occasionally a mutation for dark coloration in the moths was expressed but these expressions were 'eaten' and removed from the gene pool rather quickly because they were silhouetted against the light tree bark.

With industrialization 'soot' began accumulating on the tree bark and the trees turned dark brown/black. The drak moths now were very well camouflaged while the white, dominate moth, was silhouetted.


In a very short time the dark mutation became the dominant moth species.

Pesse (There is no good or bad, there only is what is.) Mist


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: Sentient, Intelligent, or Human? new [Re: Pess]
      #5944706 - 06/28/13 12:23 PM

One day, as I was walking into the school where I had taught, I saw a moth on the exterior brick wall; about the size of a deck of playing cards. I was stunned by what I saw. So stunned I took it to the biology teacher for display to students if he so chose.

The moth had exactly the same appearance as a tree leaf; of light green color, but the same delicate and complex appearance of veins on a leaf. Had this moth decided to be in the respective tree, I could have touched it with my nose and not seen it.


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Ravenous
sage


Reged: 11/14/09

Loc: UK
Re: Sentient, Intelligent, or Human? new [Re: Pess]
      #5944719 - 06/28/13 12:35 PM

Quote:

If you have a religiously static environment you still get evolution.



Think of sexual selection. Male peacocks have elaborately oversized tail feathers, which are probably quite dangerous to own in the wild; their ladies are drab brown, but have a liking for overly decorated males.

I'm not sure how a cycle like that starts, but once it does, selection occurs even if the environment is unchanging and the original creatures are well adapted to it. The male gets to father more chicks if he has the right plumage; the female's male chicks are more likely to be successful if she selects the right male herself.


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Pess
(Title)
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Reged: 09/12/07

Loc: Toledo, Ohio
Re: Sentient, Intelligent, or Human? new [Re: Ravenous]
      #5944930 - 06/28/13 02:46 PM

Quote:


Think of sexual selection. Male peacocks have elaborately oversized tail feathers, which are probably quite dangerous to own in the wild; their ladies are drab brown, but have a liking for overly decorated males.

I'm not sure how a cycle like that starts, but once it does, selection occurs even if the environment is unchanging and the original creatures are well adapted to it. The male gets to father more chicks if he has the right plumage; the female's male chicks are more likely to be successful if she selects the right male herself.




Good thing human men wear clothes.

Pesse (Otherwise, I shudder to think what selection pressures might be brought to bare.....) Mist


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scopethis
Postmaster
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Reged: 05/30/08

Loc: Kingman, Ks
Re: Sentient, Intelligent, or Human? [Re: Pess]
      #5945067 - 06/28/13 03:45 PM

yep, god made people naked and then covered them up..decisions, decisions, decisions....

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shawnhar
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Reged: 06/25/10

Loc: Knoxville, TN
Re: Sentient, Intelligent, or Human? new [Re: scopethis]
      #5945158 - 06/28/13 04:44 PM

Well, I guess if you believe in that silly sort of thing...
We aint got no fur man, had to do something...
REAl people almost never wear clothes.


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WaterMasterAdministrator
Moat Keeper
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Reged: 02/17/10

Loc: Southeast Idaho, USA
Re: Sentient, Intelligent, or Human? new [Re: shawnhar]
      #5945478 - 06/28/13 07:52 PM

Evolution is the result of differential reproduction. That is, the genotype that produces the most viable offspring has a higher relative fitness. The 'reason' for this differential can be, literally, anything.

Even in a 'static' environment (there's not really such a thing, but we can make the assumption for illustrative purposes), competition for resources (food, light, water, mates, refugia, etc.) is a constant selective pressure. Any competitive advantage (conferred by difference in genotype) will result in differential reproduction. The moth example mentioned above is the 'textbook' illustration of natural selection (and in this case, differential predation resulted in differential reproduction). Competition can also result in radiative speciation, as in Darwin's finches, where competition for food was the primary selective force. Peacocks, or any 'showy' bird is a great example of yet another selective pressure (and evolutionary biology is rife with stories of 'runaway' sexual selection).

Natural selection works on individuals, evolution occurs on the population level. As I used to tell my second year ecology students, "It's all about your baby's babies, baby".

And, we're getting way off topic.

But now that we've discussed selective pressure a little, I'll ask my question again: What might be the selective pressures that result in the appearance of 'mind'?

Edited by WaterMaster (06/28/13 07:57 PM)


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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Sentient, Intelligent, or Human? new [Re: Pess]
      #5945566 - 06/28/13 08:53 PM

Quote:


I'm not sure I get this line of thought.

If you have a religiously static environment you still get evolution. That environment will select what gene expressions work best to date, not necessarily what work best out of all possible combinations.

So despite a never changing environment some mutations will occur at random that work 'better' than what has worked for eons and thus the new characteristic will allow that species to out compete its brethren which may have dominated for eons.




While this is true, it's not the whole story. A genetic variation can fix within a population even in the absence of selection. That's the basis of genetic drift. Mutations come and go. Some increase in the population merely due to the chances inherent in reproduction, and some decrease. Occasionally a variation will increase to the point where it achieves critical mass, and finds itself monopolizing its particular gene, for no apparent reason. This happens most often in small, genetically isolated populations that are more sensitive to random changes. It would be like a mutation for a front-tooth gap occurring in an individual member of population that until then had all gapless front teeth. If, for reasons totally unrelated to the gap, that mutation succeeds in replicating for a few generations and becomes established, it's possible that eventually ALL the members of that population will have the gap, and the hapless gapless gene would have simply been snuffed out.

That's evolution, but it's not selection. It's actually pretty common.


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Otto Piechowski
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Reged: 09/20/05

Loc: Lexington, KY
Re: Sentient, Intelligent, or Human? new [Re: llanitedave]
      #5945775 - 06/28/13 11:01 PM

The very pronounced gap between my two front teeth is genetic?

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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Sentient, Intelligent, or Human? new [Re: Otto Piechowski]
      #5945791 - 06/28/13 11:14 PM

That depends on whether you got them for Christmas.

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Mister T
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Reged: 02/01/08

Loc: Upstate NY
Re: Sentient, Intelligent, or Human? new [Re: llanitedave]
      #5946053 - 06/29/13 07:25 AM

or from Hockey!!

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scopethis
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Reged: 05/30/08

Loc: Kingman, Ks
Re: Sentient, Intelligent, or Human? new [Re: Mister T]
      #5946805 - 06/29/13 03:49 PM

if all this mutation/evolution stuff is true, how much longer do we have to wait before our ape cousins start acting like us??

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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Sentient, Intelligent, or Human? new [Re: scopethis]
      #5947367 - 06/30/13 12:02 AM

There's no reason why they ever should. Three million years ago "humanity" was an empty niche. Now it's filled.

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shawnhar
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Loc: Knoxville, TN
Re: Sentient, Intelligent, or Human? new [Re: llanitedave]
      #5947986 - 06/30/13 12:43 PM

It is also possible 3 million years could produce another sentient hominid branch (kind of like us). Current "human" progress will destroy the current ape habitat. They already have serious enviornmental pressure, they may get smart or die off.

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Mister T
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Reged: 02/01/08

Loc: Upstate NY
Re: Sentient, Intelligent, or Human? new [Re: scopethis]
      #5948022 - 06/30/13 01:02 PM

how long does evolution go forward before it goes into reverse??

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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Sentient, Intelligent, or Human? new [Re: Mister T]
      #5948931 - 07/01/13 12:11 AM

There is no forward or reverse. The only "direction" in evolution is towards adaptation to current conditions. But there's no advance prediction as to what those adaptations will be.

Or whether they will succeed.

Edited by llanitedave (07/01/13 12:15 AM)


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scopethis
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Re: Sentient, Intelligent, or Human? new [Re: llanitedave]
      #5949099 - 07/01/13 04:17 AM

gills on humans would be nice

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Mister T
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Reged: 02/01/08

Loc: Upstate NY
Re: Sentient, Intelligent, or Human? new [Re: llanitedave]
      #5949175 - 07/01/13 07:06 AM

agreed

but sometimes human behavior suggests otherwise


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Ravenous
sage


Reged: 11/14/09

Loc: UK
Re: Sentient, Intelligent, or Human? new [Re: WaterMaster]
      #5949253 - 07/01/13 08:41 AM

Quote:


But now that we've discussed selective pressure a little, I'll ask my question again: What might be the selective pressures that result in the appearance of 'mind'?



I might get ridiculed for saying this, but I suspect it's just the peacock's tail again. I'm not qualified to say this (not having a personality of my own) but I guess that "personality" (let's call it that) is a mere selection pressure for courtship.

Communication and learning skills for a social animal are a useful survival tool, emotions like empathy for our offspring and partners are ancient instincts, but our relatively advanced personality traits originally were (in my opinion) just another random criterion used in selecting a mate. We also imagine they make us more likely to survive in the future - that's debatable - but their origins must have been much more grounded.


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