The Eye

[crazybean]

I put this in the religion page before noticing this topic

 

 

I personally believe in evoloution, but this is a very strange topic:

How has an eye so perfect been evolved, with a retina, optic nerve, iris, pigment, pupil, lens etc...?

In a debate we had at my school, the people against's response was that other animals had better eyes than us, so I just want to make it clear I am talking about the eye, not the human eye.

Also, if it has evolved, what did it evolve from?

What was it before it became a thing to see?

I want to make it clear that I'm not a loony who doesn't believe in evolution despite all the compounding evidence, I merely want to see if anyone has suggestions on this?

[crazybean]

I put this in the religion page before noticing this topic

 

 

I personally believe in evoloution, but this is a very strange topic:

How has an eye so perfect been evolved, with a retina, optic nerve, iris, pigment, pupil, lens etc...?

In a debate we had at my school, the people against's response was that other animals had better eyes than us, so I just want to make it clear I am talking about the eye, not the human eye.

Also, if it has evolved, what did it evolve from?

What was it before it became a thing to see?

I want to make it clear that I'm not a loony who doesn't believe in evolution despite all the compounding evidence, I merely want to see if anyone has suggestions on this?

[AngelicTaboo]

I reckon the eye had evolved as a defense mechanism. As evolution goes we were all first bacteria then cockroaches > rats> squirels> etc...>etc...

 

Also if you look how some insects who don't have eyes some display phototaxis traveling in response to light, maggots express negative phototaxis since they move away from light so they can burrow in the dark away from preditors also dark places have moist areas so that it keeps the maggots skin moist in order from them to survive puberty.

 

Like this defense mechanism I think selective breeding from survival of the fittest has somehow manged to create an eye like stimulus and therefore has been carried along the genetic line so that mammals have this stimulus to protect them selves away from danger...

 

I maybe wrong about this but this is my view anyway...

[AngelicTaboo]

I reckon the eye had evolved as a defense mechanism. As evolution goes we were all first bacteria then cockroaches > rats> squirels> etc...>etc...

 

Also if you look how some insects who don't have eyes some display phototaxis traveling in response to light, maggots express negative phototaxis since they move away from light so they can burrow in the dark away from preditors also dark places have moist areas so that it keeps the maggots skin moist in order from them to survive puberty.

 

Like this defense mechanism I think selective breeding from survival of the fittest has somehow manged to create an eye like stimulus and therefore has been carried along the genetic line so that mammals have this stimulus to protect them selves away from danger...

 

I maybe wrong about this but this is my view anyway...

[Auburngirl05]

When in doubt, try "Talk Origins."

http://www.talkorigins.org/indexcc/CB/CB301.html

[Auburngirl05]

When in doubt, try "Talk Origins."

http://www.talkorigins.org/indexcc/CB/CB301.html

[Mokele]

Actually, the eye is far from perfect, and a major imperfection is actually a hint of how it evolved.

 

Our retina is on backwards. Yep. All the rods and cones are pointing *away* from the light, and only catch light reflected from the back of the eye. Additionally, the rods and cones are supported on a membrane called the retinal pigment epithelium, which is anchors to the back of the eye only at a few key points. These connections are also pretty weak, which is why a strong blow to the head can cause a detatched retina.

 

How this came to be can be seen in one of the few living non-verebrate chordates, the lancet. It has a dorsal hollow nerve cord, and just before the tip it has an eyespot. The eyespot has photosensitive cells like our rods and cones, but they're pointed inwards, towards the central hollow of the nerve cord, to protect them from damage. As our eyes evolved, they sort of "puckered out" around this spot. I'm having a hard time explaining it (I could draw it fine, though). Imagine that the area in front of and behind and to the sides of the eyespot became raised ridges, and they all raised higher and higher, cupping around it, until the former outside of the eyespot is at the bottom of a big "cup". That gives you a rough idea, and explains the curious orientation of cells in our eyes.

 

Mokele

[Mokele]

Actually, the eye is far from perfect, and a major imperfection is actually a hint of how it evolved.

 

Our retina is on backwards. Yep. All the rods and cones are pointing *away* from the light, and only catch light reflected from the back of the eye. Additionally, the rods and cones are supported on a membrane called the retinal pigment epithelium, which is anchors to the back of the eye only at a few key points. These connections are also pretty weak, which is why a strong blow to the head can cause a detatched retina.

 

How this came to be can be seen in one of the few living non-verebrate chordates, the lancet. It has a dorsal hollow nerve cord, and just before the tip it has an eyespot. The eyespot has photosensitive cells like our rods and cones, but they're pointed inwards, towards the central hollow of the nerve cord, to protect them from damage. As our eyes evolved, they sort of "puckered out" around this spot. I'm having a hard time explaining it (I could draw it fine, though). Imagine that the area in front of and behind and to the sides of the eyespot became raised ridges, and they all raised higher and higher, cupping around it, until the former outside of the eyespot is at the bottom of a big "cup". That gives you a rough idea, and explains the curious orientation of cells in our eyes.

 

Mokele

[mak10]

Our retina is on backwards. Yep. All the rods and cones are pointing *away* from the light, and only catch light reflected from the back of the eye.

 

how is that an imperfection?? I asked my biology teacher about this since this intrigued me and she's like its more of a necessity since warm-blooded vertebrates like us require some very good amount of oxygen to keep the photoreceptors functioning.... and the only way to accomplish this, without compensating on the very important functions of the retinal epithelium, would be the inverted eye arrangement. Although I have trouble understanding the detailed mechanism, in the context of natural selection, had the inverted arrangement possessed an imperfection (and thus a disadvantage),then, why, pray tell, would it have evolved from the non-inverted arrangement (since basically, we know that vertebrates evolved from invertebrates, which possess this non-inverted eye, right?), in the first place??

 

-mak10

[mak10]

Our retina is on backwards. Yep. All the rods and cones are pointing *away* from the light, and only catch light reflected from the back of the eye.

 

how is that an imperfection?? I asked my biology teacher about this since this intrigued me and she's like its more of a necessity since warm-blooded vertebrates like us require some very good amount of oxygen to keep the photoreceptors functioning.... and the only way to accomplish this, without compensating on the very important functions of the retinal epithelium, would be the inverted eye arrangement. Although I have trouble understanding the detailed mechanism, in the context of natural selection, had the inverted arrangement possessed an imperfection (and thus a disadvantage),then, why, pray tell, would it have evolved from the non-inverted arrangement (since basically, we know that vertebrates evolved from invertebrates, which possess this non-inverted eye, right?), in the first place??

 

-mak10

[Mokele]

how is that an imperfection??

 

Reduced sensitivity to light, and the whole problem of "detatched retinas".

 

I asked my biology teacher about this since this intrigued me and she's like its more of a necessity since warm-blooded vertebrates like us require some very good amount of oxygen to keep the photoreceptors functioning.... and the only way to accomplish this, without compensating on the very important functions of the retinal epithelium, would be the inverted eye arrangement

 

I'm sorry, but I don't buy that in the least. There's no reason I can think of that the eye could not function perfectly well with a highly vascularized back wall, rather than the peculiar arrangement we have. On top of that, her logic about warm-blooded animals needing it is similarly off, for two reasons: 1) I cannot think of why a human eye needs more energy than, say, a lizard eye, since both are similarly acute and 2) the vertebrate eye is present in this form in *all* vertebrates, including cold-bloods (which are the vast majority of species anyway).

 

Although I have trouble understanding the detailed mechanism, in the context of natural selection, had the inverted arrangement possessed an imperfection (and thus a disadvantage),then, why, pray tell, would it have evolved from the non-inverted arrangement

 

It evolved from an inverted eye, that or the original chordates. At the time, the inverted configuation was preferable. Because of developmental constraints, it stayed that way.

 

The power of natural selection is not limitless. There are many developmental constraints on organisms, in which the possible traits that can be manifested are limited by embryological development. For instance, many herbivores like deer would be well served by having an extra pair of eyes in the back of their heads. This has never evolved because (among other reasons), vertebrates are only "programmed" for two eyes, and growing more would require a *huge* restructuring of developmental genes. Why do all vertebrates have a dorsal hollow nerve cord? It can't *always* be beneficial in *all* of their varied circumstances, can it? The answer is developmental constraints; alteration of the developmental genes almost always (I'm tempted to say always) results in grotesque deformities.

 

In short, we often get stuck with sub-par traits because there's no readily conceivable path to change them without massive damage to the organism's fitness.

 

since basically, we know that vertebrates evolved from invertebrates, which possess this non-inverted eye, right?

 

Erm, yes and no. Vertebrates *did* evolve from invertebrates, but those inverts only possessed *very* simple optical systems, little more than photoreceptors that tell the difference between light and dark. In vertebrates, those primitive cells were incorporated into one large structure (the vert. eye), while various inverts lost them or developed different systems (squid eyes, insect eyes, etc).

 

Iirc, the sort of "eye" most likely in our ancestors was probably like the eyespot of a planaria (flatworm), a very simple cluster of light-sensitive cells that could distinguish between light and dark.

 

Mokele

[Mokele]

how is that an imperfection??

 

Reduced sensitivity to light, and the whole problem of "detatched retinas".

 

I asked my biology teacher about this since this intrigued me and she's like its more of a necessity since warm-blooded vertebrates like us require some very good amount of oxygen to keep the photoreceptors functioning.... and the only way to accomplish this, without compensating on the very important functions of the retinal epithelium, would be the inverted eye arrangement

 

I'm sorry, but I don't buy that in the least. There's no reason I can think of that the eye could not function perfectly well with a highly vascularized back wall, rather than the peculiar arrangement we have. On top of that, her logic about warm-blooded animals needing it is similarly off, for two reasons: 1) I cannot think of why a human eye needs more energy than, say, a lizard eye, since both are similarly acute and 2) the vertebrate eye is present in this form in *all* vertebrates, including cold-bloods (which are the vast majority of species anyway).

 

Although I have trouble understanding the detailed mechanism, in the context of natural selection, had the inverted arrangement possessed an imperfection (and thus a disadvantage),then, why, pray tell, would it have evolved from the non-inverted arrangement

 

It evolved from an inverted eye, that or the original chordates. At the time, the inverted configuation was preferable. Because of developmental constraints, it stayed that way.

 

The power of natural selection is not limitless. There are many developmental constraints on organisms, in which the possible traits that can be manifested are limited by embryological development. For instance, many herbivores like deer would be well served by having an extra pair of eyes in the back of their heads. This has never evolved because (among other reasons), vertebrates are only "programmed" for two eyes, and growing more would require a *huge* restructuring of developmental genes. Why do all vertebrates have a dorsal hollow nerve cord? It can't *always* be beneficial in *all* of their varied circumstances, can it? The answer is developmental constraints; alteration of the developmental genes almost always (I'm tempted to say always) results in grotesque deformities.

 

In short, we often get stuck with sub-par traits because there's no readily conceivable path to change them without massive damage to the organism's fitness.

 

since basically, we know that vertebrates evolved from invertebrates, which possess this non-inverted eye, right?

 

Erm, yes and no. Vertebrates *did* evolve from invertebrates, but those inverts only possessed *very* simple optical systems, little more than photoreceptors that tell the difference between light and dark. In vertebrates, those primitive cells were incorporated into one large structure (the vert. eye), while various inverts lost them or developed different systems (squid eyes, insect eyes, etc).

 

Iirc, the sort of "eye" most likely in our ancestors was probably like the eyespot of a planaria (flatworm), a very simple cluster of light-sensitive cells that could distinguish between light and dark.

 

Mokele

[Skye]

Here's a picture of cross sections of different eyes from polychaete worms. You can see the variety, from a fairly simple depression containing photoreceptors, to last one which is fairly similar to ours.

[Skye]

Here's a picture of cross sections of different eyes from polychaete worms. You can see the variety, from a fairly simple depression containing photoreceptors, to last one which is fairly similar to ours.

[mak10]

Reduced sensitivity to light, and the whole problem of "detatched retinas".

 

I am not an expert in this, which is why I need to ask my superiors. but can you give me any experimental evidence for this... that a non-inverted eye would increase resolution and acuity of the eye than the inverted arrangement?? no doubt, its going to be more sensitive to light, i agree.... but the question is more of its maintenance. can it maintain that sensitivity for an appreciable period of time, taking in account of the fact of the increased distance of the retinal epithelium (that is actually very important for the proper functioning of the photoreceptor cells!) from the photoreceptors in a non-inverted arrangement? Also, how would the non-inverted eye solve the problem of alleviating the risk of a detached retina??

 

On top of that, her logic about warm-blooded animals needing it is similarly off, for two reasons: 1) I cannot think of why a human eye needs more energy than, say, a lizard eye, since both are similarly acute

 

do lizard eyes possess a similar density of photoreceptor cells as the human eye? if yes, then I would agree with you.

 

2) the vertebrate eye is present in this form in *all* vertebrates, including cold-bloods (which are the vast majority of species anyway).

 

agreed, but the density of the the photoreceptors in different species are different and I think that determines the energy considerations.

 

It evolved from an inverted eye, that or the original chordates.

 

so the ancestral invertebrates (from which the chordates had evolved) also had the inverted arrangement??

 

Furthermore, there was a very good article on the American Scientist entitled How the Retina works and it had something at the end about certain ganglions (which, BTW, are facing towards the incoming light) working as a photoreceptor itself... along with the fact that they are necessary to sharpen the vision. But nonetheless, the bottom line would depend on any experimental evidence provided (otherwise this entire theory of the non-inverted being better than an inverted eye is nothing more than a mere conjecture!).

 

its been also said that the inverted arrangement we have is so sensitive as it will produce an electrical signal even from a single photon (!!)... that it really defeats the purpose of having a non-inverted eye.... don't you think?? just my thoughts....

 

-mak10

[mak10]

Reduced sensitivity to light, and the whole problem of "detatched retinas".

 

I am not an expert in this, which is why I need to ask my superiors. but can you give me any experimental evidence for this... that a non-inverted eye would increase resolution and acuity of the eye than the inverted arrangement?? no doubt, its going to be more sensitive to light, i agree.... but the question is more of its maintenance. can it maintain that sensitivity for an appreciable period of time, taking in account of the fact of the increased distance of the retinal epithelium (that is actually very important for the proper functioning of the photoreceptor cells!) from the photoreceptors in a non-inverted arrangement? Also, how would the non-inverted eye solve the problem of alleviating the risk of a detached retina??

 

On top of that, her logic about warm-blooded animals needing it is similarly off, for two reasons: 1) I cannot think of why a human eye needs more energy than, say, a lizard eye, since both are similarly acute

 

do lizard eyes possess a similar density of photoreceptor cells as the human eye? if yes, then I would agree with you.

 

2) the vertebrate eye is present in this form in *all* vertebrates, including cold-bloods (which are the vast majority of species anyway).

 

agreed, but the density of the the photoreceptors in different species are different and I think that determines the energy considerations.

 

It evolved from an inverted eye, that or the original chordates.

 

so the ancestral invertebrates (from which the chordates had evolved) also had the inverted arrangement??

 

Furthermore, there was a very good article on the American Scientist entitled How the Retina works and it had something at the end about certain ganglions (which, BTW, are facing towards the incoming light) working as a photoreceptor itself... along with the fact that they are necessary to sharpen the vision. But nonetheless, the bottom line would depend on any experimental evidence provided (otherwise this entire theory of the non-inverted being better than an inverted eye is nothing more than a mere conjecture!).

 

its been also said that the inverted arrangement we have is so sensitive as it will produce an electrical signal even from a single photon (!!)... that it really defeats the purpose of having a non-inverted eye.... don't you think?? just my thoughts....

 

-mak10

[AngelicTaboo]

Here's a picture of cross sections of different eyes from polychaete worms. You can see the variety, from a fairly simple depression containing photoreceptors, to last one which is fairly similar to ours.

 

I guess it proves my theory might just be correct...

[AngelicTaboo]

Here's a picture of cross sections of different eyes from polychaete worms. You can see the variety, from a fairly simple depression containing photoreceptors, to last one which is fairly similar to ours.

 

I guess it proves my theory might just be correct...

[Guest ImpFetus]

The human eye actually has many imperfect qualities, so I would not say it perfect. Photoreceptors behind retina, blind spot for central nerve cord, ect. A Octopuses eyes are more evolved then ours!

 

The evolution of the eye of the last .5-1 billion years most likely started out with photosensitive cells, then photosensitive cells in a depression for locating direction of light, pin hole eye depression for crudely focusing light, then transparent membranes, then corneas, ect. It is actually very traceable as all of these earlier stages still exist in some animals.

[Guest ImpFetus]

The human eye actually has many imperfect qualities, so I would not say it perfect. Photoreceptors behind retina, blind spot for central nerve cord, ect. A Octopuses eyes are more evolved then ours!

 

The evolution of the eye of the last .5-1 billion years most likely started out with photosensitive cells, then photosensitive cells in a depression for locating direction of light, pin hole eye depression for crudely focusing light, then transparent membranes, then corneas, ect. It is actually very traceable as all of these earlier stages still exist in some animals.

[Mokele]

can it maintain that sensitivity for an appreciable period of time, taking in account of the fact of the increased distance of the retinal epithelium (that is actually very important for the proper functioning of the photoreceptor cells!) from the photoreceptors in a non-inverted arrangement?

 

Why would they be farther away in a non-inverted system? Think of it as if the retinal epithelium in our eyes, photoreceptors and all, were taken out, flipped over, and placed back against the back wall of the eye (in terms of geometry, not that such an operation could work). They'd still be the same distance from the retinal epithelium, but facing the other way around.

 

Also, how would the non-inverted eye solve the problem of alleviating the risk of a detached retina??

 

As it stands, you have the rigid back of the eye, and the retinal epithelium floats above it, anchored only by a few connection points. More connection points would impede vision in us. But if the system were non-inverted, you could add as many connection points as you wished without jeopardizing function, which would strengthen things considerably. Also, you could add more capiliaries, and add more nerves, because the connection points all of those use (which currently interfere with vision if there are too many) could be as big as you wanted in a non-inverted eye.

 

but can you give me any experimental evidence for this... that a non-inverted eye would increase resolution and acuity of the eye than the inverted arrangement??

 

Sadly, my knowledge is mostly limited to vertebrates (and those invertebrates that taste good or make good reptile food). That doesn't mean such non-inverted eyes don't exist, only that I personally don't know of them. If other posters know of certain invertebrates with that configuration, I'd be grateful.

 

do lizard eyes possess a similar density of photoreceptor cells as the human eye? if yes, then I would agree with you.

 

Well, it varies with species, but generally yes.

 

so the ancestral invertebrates (from which the chordates had evolved) also had the inverted arrangement??

 

Yep. Photoreceptor cells are delicate, so exposing them to the external environment wouldn't be good. And, when you're small and pretty much transparent, inverting them solves the problem nicely.

 

otherwise this entire theory of the non-inverted being better than an inverted eye is nothing more than a mere conjecture!

 

Well, it may be so, but the real point wasn't *actually* whether a different system is all-around better. It was that the eye *isn't* perfect, and that certain inperfect features of it are a consequence of both evolution and developmental constraints on evolution.

 

That's basically what I'm saying: The eye isn't perfect, and those imperfections are both evidence of it's state as an evolved feature, and a note on the limits of evolution.

 

Mokele

[Mokele]

can it maintain that sensitivity for an appreciable period of time, taking in account of the fact of the increased distance of the retinal epithelium (that is actually very important for the proper functioning of the photoreceptor cells!) from the photoreceptors in a non-inverted arrangement?

 

Why would they be farther away in a non-inverted system? Think of it as if the retinal epithelium in our eyes, photoreceptors and all, were taken out, flipped over, and placed back against the back wall of the eye (in terms of geometry, not that such an operation could work). They'd still be the same distance from the retinal epithelium, but facing the other way around.

 

Also, how would the non-inverted eye solve the problem of alleviating the risk of a detached retina??

 

As it stands, you have the rigid back of the eye, and the retinal epithelium floats above it, anchored only by a few connection points. More connection points would impede vision in us. But if the system were non-inverted, you could add as many connection points as you wished without jeopardizing function, which would strengthen things considerably. Also, you could add more capiliaries, and add more nerves, because the connection points all of those use (which currently interfere with vision if there are too many) could be as big as you wanted in a non-inverted eye.

 

but can you give me any experimental evidence for this... that a non-inverted eye would increase resolution and acuity of the eye than the inverted arrangement??

 

Sadly, my knowledge is mostly limited to vertebrates (and those invertebrates that taste good or make good reptile food). That doesn't mean such non-inverted eyes don't exist, only that I personally don't know of them. If other posters know of certain invertebrates with that configuration, I'd be grateful.

 

do lizard eyes possess a similar density of photoreceptor cells as the human eye? if yes, then I would agree with you.

 

Well, it varies with species, but generally yes.

 

so the ancestral invertebrates (from which the chordates had evolved) also had the inverted arrangement??

 

Yep. Photoreceptor cells are delicate, so exposing them to the external environment wouldn't be good. And, when you're small and pretty much transparent, inverting them solves the problem nicely.

 

otherwise this entire theory of the non-inverted being better than an inverted eye is nothing more than a mere conjecture!

 

Well, it may be so, but the real point wasn't *actually* whether a different system is all-around better. It was that the eye *isn't* perfect, and that certain inperfect features of it are a consequence of both evolution and developmental constraints on evolution.

 

That's basically what I'm saying: The eye isn't perfect, and those imperfections are both evidence of it's state as an evolved feature, and a note on the limits of evolution.

 

Mokele

[Mokele]

Ahh, google to the rescue! Apparently the eyes of cephalopods (octopi and the like) are "non-inverted".

 

I'll do more poking around on it later, because I'm hungry now, then I have errands to run.

 

Mokele

[Mokele]

Ahh, google to the rescue! Apparently the eyes of cephalopods (octopi and the like) are "non-inverted".

 

I'll do more poking around on it later, because I'm hungry now, then I have errands to run.

 

Mokele

[mak10]

thanks for the info mokele... i'll look into this cephalopods thing when I've the time. but it would have been more appealing if i could find some real experiment being carried out on this... as to whther the non-inverted arrangement would work better in human eyes, but i understand that this might raise some ethical issues, so i'll stay quiet

 

but i will make some comments on your post,

 

Think of it as if the retinal epithelium in our eyes, photoreceptors and all, were taken out, flipped over, and placed back against the back wall of the eye (in terms of geometry, not that such an operation could work). They'd still be the same distance from the retinal epithelium, but facing the other way around.

 

but then, where would you place the choroidal capillaries, that suppy blood to the retinal epithelium?? also, i learned that the bipolar and ganglion cells present are actually very important in being where they are, i.e - in between the incoming light and the photoreceptors. I finally found a link to the American Scientist article I was talking about:

 

How the Retina Works

 

Its by Dr. Helga Kolb who is considered an authority in the human retina. The article is a bit long and heavily detailed, so i'll just quote a few passages from her paper to highlight my point:

 

First off, she starts off explaining the very thing we are discussing about (all emphasis in italics are mine):

 

Intuitively, one might expect that the surface of the retina (the layer exposed to the liquid in the eyeball's vitreous chamber) would contain the sensory cells, the photoreceptors, but actually these cells lie at the very back of the retina; light rays must pass through the entire retina before reaching pigment molecules to excite. This is because the pigment-bearing membranes of the photoreceptors have to be in contact with the eye's pigment epithelial layer, which provides a steady stream of the vital molecule, retinal or vitamin A. Retinal becomes fixed in the photoreceptors' opsin proteins, where this small molecule changes its conformation in response to photons, or packets of light.

 

Also unknown to me was the presence of horizontal cells, let alone their vital function. These are also present between the photoreceptors and the incoming light. About them she writes:

 

Horizontal cells respond to more than the photoreceptors that link to them. Feedback signals from the inner plexiform layer influence horizontal-cell activity as well. These feedback signals are transmitted via substances such as dopamine, nitric oxide and retinoic acid. The result is that horizontal cells modulate the photoreceptor signal under different lighting conditions—allowing signaling to become less sensitive in bright light and more sensitive in dim light—as well as shaping the receptive field of the bipolar cells, as we have seen.

 

She also gives us some good amount of very detailed information regarding the ganglion and amacrine cells that are also involved in the processing. I wouldn't wanna quote all that here since this can really lengthen the post and I don't like long posts myself ! Nonetheless, anyone interested can go ahead and read it up... its very high stuff but very interesting.

 

You also write:

 

so the ancestral invertebrates (from which the chordates had evolved) also had the inverted arrangement??

 

 

Yep. Photoreceptor cells are delicate, so exposing them to the external environment wouldn't be good. And, when you're small and pretty much transparent, inverting them solves the problem nicely.

 

but cephalopods are also invertebrates, arent they? i dont know if they're small or transparent, but they do appear to have the non-inverted arrangement, as you've said. that would mean that the ancestral invertebrates changed from the advantageous inverted retina to the not-so-advantageous non-inverted retina and it bloomed in cephalopods. is that evolutionarily possible?? i've got some more questions since this is all very interesting and stuff and i am no expert, (which is why i've to rely on authorities ). besides, i've to sleep... so later!

 

-mak10