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Author Topic:   Brain Evolution
Straggler
Member (Idle past 17 days)
Posts: 10285
From: London England
Joined: 09-30-2006


(1)
Message 1 of 43 (480439)
09-03-2008 2:36 PM


How did brains evolve? Why did brains evolve? What were the precursors to brains in evolutionary terms? Do we have living examples of various stages of brain evolution in existence now? If so what are they are what do they tell us about the evolutionary paths required to eventually lead to creatures with brains?

How does the evolution of consciousness tie in with the evolutionary development of brains?
Human brains are considered to be the pinnacle of brian evolution but how clever are other animals and what evolutionary pressures could have led to the development of their brains? Are they the same pressures that led to human intelligence or are they the product of different factors and parallel development?

Have brains evolved only once or, like eyes, have they evolved via a variety of paths?

I have no real knowledge on this subject, no axe to grind and no deep insights to share. I am asking thee questions because I know that I do not know the answers. Not because I think that I do. I ask because I am interested to know what the current scientific thinking and theories are regards this matter.

If this list of questions is not considered complete enough to be a topic in it's own right then I fully understand and will get googling instead.
However I thought it might be a subject that EvC memebers have some interest in, and knowledge of. It is also not a topic I have seen discussed here previously.

If promoted I guess it should go in the Biological Evolution area.

Edited by Straggler, : No reason given.


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AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 2 of 43 (480443)
09-03-2008 3:20 PM


Thread moved here from the Proposed New Topics forum.

  
Agobot
Member (Idle past 3917 days)
Posts: 786
Joined: 12-16-2007


Message 3 of 43 (480450)
09-03-2008 4:33 PM


As far as i can tell - the brain is just another tool for survival in the survival of the fittest game. In that respect it's not much different to claws, wings, fangs and poison. But with regard to power - it's the ultimate weapon that gives us humans the edge over all other species.

  
onifre
Member (Idle past 1338 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 4 of 43 (480452)
09-03-2008 4:49 PM
Reply to: Message 1 by Straggler
09-03-2008 2:36 PM


Straggler writes,


How did brains evolve? Why did brains evolve? What were the precursors to brains in evolutionary terms? Do we have living examples of various stages of brain evolution in existence now? If so what are they are what do they tell us about the evolutionary paths required to eventually lead to creatures with brains?

Heres a great link that should answer many of your questions.
http://faculty.ed.uiuc.edu/g-cziko/wm/05.html

I'll try to quote a few things from it to answer some of your questions.

Your question "What were the precursors in evolutionary terms?"

quote:
All living cells are surrounded by a cell membrane that separates the special chemical composition of its interior from that of the external world. This difference in chemical composition results in a small electrical potential between the inside and outside of the cell, in much the same way that a voltage exists between the two sides of a battery. When a part of a cell's membrane is disturbed in a certain way, it loses its electrical potential, becoming depolarized at the site of the disturbance. This sudden change in electrical potential can itself be a disturbance, causing additional depolarizations along the membrane. In most cells, such depolarization would not spread far, certainly not to neighboring cells. But a few changes in the shape and arrangement of cells (in just the way that neurons are fashioned) permits depolarization to propagate quickly from one neuron to the next, and allows it to travel quickly as an electrochemical signal from one end of an animal to the other.

Your question "Why did the brain evolve?"..."How did brains evolve?"

quote:
It is not possible to know exactly why the human brain evolved as it did, but consideration of the structural evolution of the brain and results of comparative research on human and nonhuman brains provides some useful clues. It is now believed that during the long evolution of our brain, nervous systems changed in four principal ways. First, they became increasingly centralized in architecture, evolving from a loose network of nerve cells (as in the jellyfish) to a spinal column and complex brain with impressive swellings at the hindbrain and forebrain. This increasingly centralized structure also became increasingly hierarchical. It appears that newer additions to the human brain took over control from the previous additions and in effect became their new masters. Accordingly, the initiation of voluntary behavior as well as the ability to plan, engage in conscious thought, and use language depend on neocortical structures. Indeed, the human neocortex can actually destroy itself if it wishes, as when a severely depressed individual uses a gun to put a bullet through his or her skull.

Second, there was a trend toward encephalization, that is, a concentration of neurons and sense organs at one end of the organism. By concentrating neural and sensory equipment in one general location, transmission time from sense organs to brain was minimized. Third, the size, number, and variety of elements of the brain increased. Finally, there was an increase in plasticity, that is, the brain's ability to modify itself as a result of experience to make memory and the learning of new perceptual and motor abilities possible.


I recommend you read the whole link Straggler, it is very detailed and should provide you with alot of answers.

Topics are,
*The Evolution of the Brain
*The Development of the Brain
*Learning and Memory: Rewiring the Brain

I hope this helped :)


"All great truths begin as blasphemies"

"I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth."--Bill Hicks

"I never knew there was another option other than to question everything"--Noam Chomsky


This message is a reply to:
 Message 1 by Straggler, posted 09-03-2008 2:36 PM Straggler has responded

Replies to this message:
 Message 5 by New Cat's Eye, posted 09-03-2008 5:01 PM onifre has responded
 Message 7 by Straggler, posted 09-03-2008 6:07 PM onifre has responded

  
New Cat's Eye
Inactive Member


Message 5 of 43 (480454)
09-03-2008 5:01 PM
Reply to: Message 4 by onifre
09-03-2008 4:49 PM


Heres a great link that should answer many of your questions.
http://faculty.ed.uiuc.edu/g-cziko/wm/05.html

Tell me you didn't go to U of I!


This message is a reply to:
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onifre
Member (Idle past 1338 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 6 of 43 (480463)
09-03-2008 5:57 PM
Reply to: Message 5 by New Cat's Eye
09-03-2008 5:01 PM


Tell me you didn't go to U of I!

LOL no sir I did not. University of Miami thank you very much;)

I just had that link saved on my laptop for a class I had on the 'Rise of Consciousness'.

I didn't want to cheat from any of my schools papers when I took the class:D

Edited by onifre, : correction in my statement.


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Straggler
Member (Idle past 17 days)
Posts: 10285
From: London England
Joined: 09-30-2006


(1)
Message 7 of 43 (480465)
09-03-2008 6:07 PM
Reply to: Message 4 by onifre
09-03-2008 4:49 PM


Brains
I hope this helped

Indeed it did. Fascinating.

So from this the conclusion is that, to the best of our knowledge, brains have developed only once in life on Earth but that the beginnings and foundations of brains go right back to some of the earliest lifeforms known.

Any thoughts (or links) on the nature and evolution of consciousness and the relation of this to brains? How "conscious" are jellyfish? Insects? Lizards? For example. (whatever the question "how conscious" even means :))


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onifre
Member (Idle past 1338 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 8 of 43 (480470)
09-03-2008 6:23 PM
Reply to: Message 7 by Straggler
09-03-2008 6:07 PM


Re: Brains
Hi Straggler,

Any thoughts (or links) on the nature and evolution of consciousness and the relation of this to brains? How "conscious" are jellyfish? Insects? Lizards? For example. (whatever the question "how conscious" even means )

I'd like to get Catholic Sci. involved in this since he and I have had discussions in the past on consciousness.

He gave me this wiki definition of sapience,
http://en.wikipedia.org/wiki/Sapience

...which seems to help understand what gives rise to consciousness.

This quote from the definition seems to be a good summary of what consciousness is

quote:
Displaying sound judgment in a complex, dynamic environment is a hallmark of wisdom.

I would also add that that is the hallmark to consciousness.

As far as the animals are concerned, CS gave me this wiki link to the mirror test that tests animals, or rather we think it tests animals, consciousness.
http://en.wikipedia.org/wiki/Mirror_test

We had a pretty good 2 page discussion on this thread,
www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=12&t=521&m=16 -->www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=12&t=521&m=16">http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=12&t=521&m=16

Sorry I don't know how to tag a specific threads.


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New Cat's Eye
Inactive Member


Message 9 of 43 (480552)
09-04-2008 10:58 AM
Reply to: Message 7 by Straggler
09-03-2008 6:07 PM


Re: Brains
Any thoughts (or links) on the nature and evolution of consciousness and the relation of this to brains? How "conscious" are jellyfish? Insects? Lizards? For example. (whatever the question "how conscious" even means :))

If by consciousness we're talking about being sapient, then I think that language is an important component.

You need to have 'words' to express complex abstract thoughts in.

http://www.livescience.com/animals/080310-primate-calls.html

quote:
By playing back recordings of calls at monkeys, Zuberbühler, Arnold and their colleagues unexpectedly found that males could arrange hacks and pyows to convey at least three different kinds of information to other monkeys — the event they witnessed, the identity of callers, and even whether they intended to travel.

Scientists had suggested that stringing different sounds together into complex ideas occurred relatively late in human evolution, speculating that such combinations only happened when doing so became easier than adding new signals to a large, unwieldy repertoire.


I'm short on time but this is an interesting topic.


This message is a reply to:
 Message 7 by Straggler, posted 09-03-2008 6:07 PM Straggler has responded

Replies to this message:
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Straggler
Member (Idle past 17 days)
Posts: 10285
From: London England
Joined: 09-30-2006


(1)
Message 10 of 43 (480603)
09-04-2008 7:49 PM
Reply to: Message 9 by New Cat's Eye
09-04-2008 10:58 AM


Re: Brains
Are mice more conscious than cockroaches?

Are dolphins more conscious than rats?

If by consciousness we're talking about being sapient, then I think that language is an important component.

I don't think consciousness and sapience are the same thing. Nor do I think language is a pre-requisite for consciousness (although it may increase it!!)

I am still not sure what is meant by the term "more conscious" even though I feel we instinctively think of increasing intelligence as resulting in increasing consciousness.

Is an insect more conscious than an insect? A dog more conscious than a fly? etc. etc. etc.


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Wounded King
Member (Idle past 2481 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 11 of 43 (480624)
09-05-2008 5:54 AM
Reply to: Message 10 by Straggler
09-04-2008 7:49 PM


Consciousness and free will?
One piece of research I remember reading about a while ago was on the question of how deterministic or stereotyped an insects behaviour was. Their results suggested that the fly's behaviour was not simply a deterministic one with any behavioural variation being caused by environmental variations but rather that the brain itself produced spontaneous flight maneuvers in a structured non-random manner (Maye et al., 2007).

Whether this is truly an example of the mechanism behind 'free will' and how it ties into consciousness is a very knotty problem.

Do more complex neural structures perhaps tend to produce more such spontaneous patterns and does the increasing complexity of these patterns and their interactions lead to what we experience as our continuing consciousness?

I'm sure Syamsu will be glad to hear science is taking more of an interest in 'free will' and decision.

TTFN,

WK


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New Cat's Eye
Inactive Member


Message 12 of 43 (480642)
09-05-2008 10:12 AM
Reply to: Message 10 by Straggler
09-04-2008 7:49 PM


Re: Brains
Are mice more conscious than cockroaches?
Are dolphins more conscious than rats?

I'd speculate yes to both.

If by consciousness we're talking about being sapient, then I think that language is an important component.

I don't think consciousness and sapience are the same thing.

Me neither, but sometimes people interchange the words.

Nor do I think language is a pre-requisite for consciousness (although it may increase it!!)

Me neither, but I do think its a pre-requisite for sapience as is conciousness. And as consciousness increases, sapience is approached.

I am still not sure what is meant by the term "more conscious" even though I feel we instinctively think of increasing intelligence as resulting in increasing consciousness.

I'd say visa versa; that increasing consciousness results in increasing intelligence.

wiki on consciousness:

quote:
Consciousness defies simple definition. It has been defined loosely as a constellation of attributes of mind such as subjectivity, self-awareness, sentience, and the ability to perceive a relationship between oneself and one's environment.

More conscious would more self-aware, it'd be having a better ability to perceive a relationship between oneself and one's environment, etc.

For example, something that doesn't have eyeballs would presumable be less aware than something that does, so it'd be less conscious (although not necessarily).

Is an insect more conscious than an insect? A dog more conscious than a fly? etc. etc. etc.

Well, getting down to the gnat's ass on where to draw the lines is practically impossible. But generally speaking, its easy to see that a dog is more conscious than a ant by looking at how they react to the environment.


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Fosdick 
Suspended Member (Idle past 3887 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 13 of 43 (480654)
09-05-2008 11:55 AM
Reply to: Message 1 by Straggler
09-03-2008 2:36 PM


Consciousness and the brain
Straggler writes:

How does the evolution of consciousness tie in with the evolutionary development of brains?


Very good question. But it begs for a definition of consciousness and assumes it's a brain-development thing. Maybe it isn't. Maybe consciousness is a state of mind, not a part of the brain. Maybe two humans differ in their respective states of consciousness on the grounds of their perceptions of reality. Maybe one person says consciousness is being closer to God, while another says it is being closer to nature. When Pat Roberston said that New Orleans was punished by Katrina because it fostered gay behavior was he more conscious than a NOAA weatherman who said it had to do with global warming?

Consciousness is a measure of correctness in reality perception. But whose reality? Was Einstein more conscious than Gandhi? Is Barack Obama more conscious than George Bush? Is a human SCUBA diver more conscious than cuttlefish in its reef?

I'm not at all sure that consciousness is an "evolving brain" thing. For humans, it's more like an "evolving symbolic language? thing. For cuttlefish, it may be more like a "evolving color pattern" thing.

—HM


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onifre
Member (Idle past 1338 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 14 of 43 (480659)
09-05-2008 1:15 PM
Reply to: Message 13 by Fosdick
09-05-2008 11:55 AM


Re: Consciousness and the brain
Hi Hoot Mon,

Maybe consciousness is a state of mind, not a part of the brain.

But wouldn't a 'state-of-mind' still require some kind of neural processing?

A 'state-of-mind' should be described more as 'Qualia, rather than consciousness.

wiki definition,
http://en.wikipedia.org/wiki/Qualia

quote:
In more philosophical terms, qualia are properties of sensory experiences.

quote:
One of the simpler, broader definitions is "The 'what it is like' character of mental states. The way it feels to have mental states such as pain, seeing red, smelling a rose, etc.'"

I would argue that consciousness at its must fundamental level is just self and environmental awareness. Therefore it not only requires one to be able to perceive its environment, it also requires that one is able to make sense of what has been perceived. Thats why the brain must be a factor in consciousness since without it we couldn't make heads or tails of any sensory information.

So if the brain evolved, so did the levels of consciousness. Perhaps a primitive self/environmental awareness localized to a small area slowly increasing as more is perceived and understood.


"All great truths begin as blasphemies"

"I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth."--Bill Hicks

"I never knew there was another option other than to question everything"--Noam Chomsky


This message is a reply to:
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Straggler
Member (Idle past 17 days)
Posts: 10285
From: London England
Joined: 09-30-2006


(1)
Message 15 of 43 (480670)
09-05-2008 2:12 PM
Reply to: Message 12 by New Cat's Eye
09-05-2008 10:12 AM


Evolving Consciousness
I agree instinctively with everything you say regarding the relationships between consciousness, sapience, intelligence et. etc.

Is it possible to conceive of a being that is "more conscious" than a human? I don't mean this in a theistic sense (I do not want to derail the therad down that route at all). I mean is it conceivable that humans (or other creatures) could evolve greater intelligence, greater sapience and greater consciousness than we currently possess?

What would such a creature be able to do that we are not capable of? What does 'more conscious' in this context actually mean?


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