Why?

Walking around Green Lake in Seattle this morning on a sunny day, this very thought occurred to me. As a perverted deviation of this thread, might we consider Earth as an evolutionary biological organism that has developed this color scheme to serve as a beacon of sorts for interstellar observers, or is it just happenstance? Our ongoing search for viable exoplanets is based on chromatic analyses of their atmospheres. Of course such a theory is based upon the ability to 'see'.
I do believe our planet is Alive. Sentient? G-d only knows!
But I was hooked on the "Gaia" theory when doing my Master's degree, too many years ago!
Our biological ability to SEE evolved from our primate ancestors, we use colors to distinguish edible fruit from unripe ones, from dangerous fruits and animals. We are just lucky we see the way we do!
What we see looks different when seen under a different set of optical equipment (we need both eyes and a brain capable of decoding the imagery). Different animals will see the world according to their "equipment". We see the same thing and we will all actually see it differently. This has always fascinated me.
 
We are just lucky we see the way we do!
This would bring this thread full circle, in response to Wendy's question, here or at Pinctada Maculata: "Are we just lucky?" Shell evolution might be categorized distinctly as visual (exterior, camoflage) and microstructure (interior, strength), our human eyes uniquely attuned to the results of the latter.

Sentience: Wouldn't wish that on our dear Earth. Look what we've done with it.
 
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I believe the most important factor is the recipient oyster, since it will be the one in charge of "feeding" nutrients to the donor cells. If the donor cells are amazing, but the recipient mollusk is having a really tough time, then the donor cells will "enjoy" the same fate.
I agree, but only to the extent of unhealthy recipients or it's situation in the environment. You can graft a green apple to a red apple tree and still yield green apples. However, when the tree becomes unhealthy does not mean it defaults to red apples on those branches. Unsightly or inedible, is all that results.

Homogeneic graft survival and pearl sac development depends on histocompatibility and blood type/flow. The same or greatly similar tissue types (alleles) and their absence of antigens. Some grafts (for lack of a better term) of internal xenogeneic infiltration (in natural pearls) are undoubtedly not the same DNA as the recipient host, but have compatible blood types absent of antigens which give rise to rejection. External borers, not so much of either, but calcareous bridging occurs nonetheless.

That's why the "irritant" thing is irritating. Irritation very often leads to other health issues, even mortality. Discounting the secondary effects bruising, bleeding, constriction or overexertion as underlying causes, irritation only applies to extrapallial pearls and blisters, not endomyostracial or interpallial grafts in general. In the aquaculture situation, mabes are extrapallial and do not require graft tissue, nor do they have pearl sacs. In which case, the colour is pretty much dictated by the outer surface of the pallial mantle of the host.
 
This would bring this thread full circle, in response to Wendy's question, here or at Pinctada Maculata: "Are we just lucky?" Shell evolution might be categorized distinctly as visual (exterior, camoflage) and microstructure (interior, strength), our human eyes uniquely attuned to the results of the latter.

Sentience: Wouldn't wish that on our dear Earth. Look what we've done with it.
To comport with one's surroundings is definitely a survival mechanism. Not all bivalves are wrapped in conchiolin, especially those within the benthic zone (buried in sediments). However, most epifaunal creatures are, and often become encrusted by other organisms, thus obscuring their visual structures. In the case of Tridacna, their mantles may appear as highly colorful and patterned. I'd suggest it's a largely survival mechanism to blend into the environment. After all, while the shells are open and the creature is actively feeding, it's mantle is highly vulnerable to the outside world.
 
What we see looks different when seen under a different set of optical equipment (we need both eyes and a brain capable of decoding the imagery). Different animals will see the world according to their "equipment". We see the same thing and we will all actually see it differently. This has always fascinated me.
Me too. "Seeing red" is a term we've gathered from the animal kingdom as it applies to fight instead of flight.
 
I once did a full day thought experiment exercise with other science minded SF fans on evolving an alien. My alien needed three to tango and that was so much fun it stayed on the floor of the ocean and didn't bother to do any more evolving.
But yes, there are many answers to the question of 'seeing' . Bees for example have very differently constructed eyes.
None of this explains why some molluscs have evolved coloured or multi-coloured shell homes (and, collaterally, why some haven't)
 
I once did a full day thought experiment exercise with other science minded SF fans on evolving an alien. My alien needed three to tango and that was so much fun it stayed on the floor of the ocean and didn't bother to do any more evolving.
But yes, there are many answers to the question of 'seeing' . Bees for example have very differently constructed eyes.
None of this explains why some molluscs have evolved coloured or multi-coloured shell homes (and, collaterally, why some haven't)
Apply Occam's razor if you will. The solution to a problem is usually the simplest one.

Iridescence is coincidental to shell strength.
 
Apply Occam's razor if you will. The solution to a problem is usually the simplest one.

Iridescence is coincidental to shell strength.
Yup! Aragonite crystals make a "mesh"-like structure, which helps dissipate direct impacts (think a fish with a beak, like a parrot fish) on the shell, by dissipating the energy throughout the entire shell. So, with less shell (thinking the environment had little CO2 and making Calcium Carbonate shells was more "expensive") you have the same effect as a thicker shell!
And if the "side effect" of having this amazingly efficient shell was iridescence...so be it! They were not even aware they added color to their protective shell.
 
This would bring this thread full circle, in response to Wendy's question, here or at Pinctada Maculata: "Are we just lucky?" Shell evolution might be categorized distinctly as visual (exterior, camoflage) and microstructure (interior, strength), our human eyes uniquely attuned to the results of the latter.

Sentience: Wouldn't wish that on our dear Earth. Look what we've done with it.
What we are still doing. Yes, our Economic system is geared towards destruction of everything that is of real value (life!). But we will not be able to change it, there are way too many powers that will keep things as they are. The system will have to collapse first. Then we could have a fighting chance...but it will be a very, very different world for the survivors. We had these long and amazing talks when we were students in the field of Ecology and Conservation Management.

So, I've decided that the only thing I can do is follow Maimonedes' philosophy of Tikkum Olam. I focus on this always, so I can also live a happy life, always living in the present moment.
 
So, I've decided that the only thing I can do is follow Maimonedes' philosophy of Tikkum Olam. I focus on this always, so I can also live a happy life, always living in the present moment.
My Google profile is Maimonides' head from his statue in the Barrio Judío of Córdoba, one of my favorite places. What a great man! Yes we can only live now, Earth was not always blue (it was white as 'Snowball Earth' and green during 'The Great Dying') and is predicted to return to those states as the movie of life accelerates in reverse, with our capable help.
 
So, I've decided that the only thing I can do is follow Maimonedes' philosophy of Tikkum Olam. I focus on this always, so I can also live a happy life, always living in the present moment.
My Google profile is Maimonides' head from his statue in the Barrio Judío of Córdoba, one of my favorite places. What a great man! Yes we can only live now, Earth was not always blue (it was white as 'Snowball Earth' and green during 'The Great Dying') and is predicted to return to those states as the movie of life accelerates in reverse, with our capable help.
Although not a follower, I agree with the philosophy that we may be better stewards of our planet. Walking in Ed Ricketts footsteps instilled that into me. Much of his work stemmed from our ability "see" things in nature and to question or interpret their purpose.

I see pearls differently than others. I don't disagree with the concept of beauty and profit, insomuch as why things are in a place and a time. Oddly enough, one of the greatest truths I've grasped came from the mouth of an eight year old girl. "Big fish eat little fish and that's just the way it is." I would like to believe that we can coexist with all other creatures, but that's not reasonable. We have canine teeth and large livers, hence we've evolved to eat other animals for survival. As humans, we can debate the subjectivity of that, while most other planetary creatures cannot. I've learned it's not one way or the other, it must be a balance.

Studying ocean sciences opens doors to greater things. I've collected acorn barnacles for spinal cord research, collected the glue from byssal threads to replace stitches in open heart surgery and monitored the uptake and retention of biotoxins in seafood. These things improve our quality of life. In a world of largely viewed "been there, done that", our oceans are woefully under-studied for the potential of so much more.

For all my years at Clayoquot, I've combined biology, paleontology and archaeology to generate a profile of changes in the earth's climate over the last three centuries. Moreover, how reactions between carbon dioxide, carbonate ions and acidification are replicated in science. The mean annual thickness of sea shells is an indicator of all of this. Though lain before us to "see", it mostly falls on deaf ears.

Not everything in nature can be explained.
 
Although not a follower, I agree with the philosophy that we may be better stewards of our planet. Walking in Ed Ricketts footsteps instilled that into me. Much of his work stemmed from our ability "see" things in nature and to question or interpret their purpose.

I see pearls differently than others. I don't disagree with the concept of beauty and profit, insomuch as why things are in a place and a time. Oddly enough, one of the greatest truths I've grasped came from the mouth of an eight year old girl. "Big fish eat little fish and that's just the way it is." I would like to believe that we can coexist with all other creatures, but that's not reasonable. We have canine teeth and large livers, hence we've evolved to eat other animals for survival. As humans, we can debate the subjectivity of that, while most other planetary creatures cannot. I've learned it's not one way or the other, it must be a balance.

Studying ocean sciences opens doors to greater things. I've collected acorn barnacles for spinal cord research, collected the glue from byssal threads to replace stitches in open heart surgery and monitored the uptake and retention of biotoxins in seafood. These things improve our quality of life. In a world of largely viewed "been there, done that", our oceans are woefully under-studied for the potential of so much more.

For all my years at Clayoquot, I've combined biology, paleontology and archaeology to generate a profile of changes in the earth's climate over the last three centuries. Moreover, how reactions between carbon dioxide, carbonate ions and acidification are replicated in science. The mean annual thickness of sea shells is an indicator of all of this. Though lain before us to "see", it mostly falls on deaf ears.

Not everything in nature can be explained.
You've said it both scientifically and poetically. Not many can do this.
 
I don't know how I missed this thread previously, but what a great one!
My thoughts are that micro habitats with micro environments exist within the broader landscape ecology. There are likely numerous factors as have been mentioned here that can impact color production. I don't have access to journals (a sad situation for my agency and me personally) but I'd like to see if any research has been done on micro habitat conditions
 
I don't have access to journals
To commiserate, if only I had all the money I spent on researching Nautilus Pompilius biology and paleontology for that thread as a continuing pearl budget!

At the risk of becoming Wendy's spokesperson, while all lines of research are fascinating and worthwhile, we could end up backsliding into 'how' vs. 'why'. Although it is clear that the former offers a road ahead, the latter does not.
 
Steve, would you be willing to share those articles with me?
Of course! Unfortunately I don't know what remains in my files, it was a long time and couple of computer crashes ago. I was subscribed to every known scientific journal. What a frenzied time that was for me proving/disproving the existence of Nautilus pearls! The faculty at University of Granada proposed that I write a doctoral thesis on Nautilus biology and the history of Nautilus research. Imagine that for a wine importer. The result, however, was burnout and my extended absence from this forum.
 
Of course! Unfortunately I don't know what remains in my files, it was a long time and couple of computer crashes ago. I was subscribed to every known scientific journal. What a frenzied time that was for me proving/disproving the existence of Nautilus pearls! The faculty at University of Granada proposed that I write a doctoral thesis on Nautilus biology and the history of Nautilus research. Imagine that for a wine importer. The result, however, was burnout and my extended absence from this forum.
The "Cloud" is now a safe repository for those hideous hard drive crashes...wish we had the Cloud back then, right? I lost my Master's thesis in one of those :(
Rather have you back at the forum than suffering burnout Steve!
 
The "Cloud" is now a safe repository for those hideous hard drive crashes...
Oh, I'm a fan. Have six clouds, one per segment of my life (I have lived a very segmented life!).

A highlight of my research still gives me chills, although it may be hard to explain or understand. I was 'live' when the definitive DNA study was published proving a long-held assumption that Cephalopoda (and not Gastropoda) originated with Monoplacophora. The shell material of monoplacophorans, discovered and named by Antonio Checa at U. Granada, is Foliated Aragonite—the precursor of nacre in the evolution of shell strength. As we were at one point convinced that we observed Foliated Aragonite under electron microscopy in purported Nautilus pearls, there was reason to believe that a genetic basis existed for the production of non-nacreous pearls by a nacreous Cephalopoda shell.

That actually remains an open, if abandoned, line of research. While DNA extraction has since proven viable for nacreous pearls, it is not yet appllicable to non-nacreous pearls, which would offer ultimate resolution of the matter.
 
Oh, I'm a fan. Have six clouds, one per segment of my life (I have lived a very segmented life!).

A highlight of my research still gives me chills, although it may be hard to explain or understand. I was 'live' when the definitive DNA study was published proving a long-held assumption that Cephalopoda (and not Gastropoda) originated with Monoplacophora. The shell material of monoplacophorans, discovered and named by Antonio Checa at U. Granada, is Foliated Aragonite—the precursor of nacre in the evolution of shell strength. As we were at one point convinced that we observed Foliated Aragonite under electron microscopy in purported Nautilus pearls, there was reason to believe that a genetic basis existed for the production of non-nacreous pearls by a nacreous Cephalopoda shell.

That actually remains an open, if abandoned, line of research. While DNA extraction has since proven viable for nacreous pearls, it is not yet appllicable to non-nacreous pearls, which would offer ultimate resolution of the matter.
Yes, DNA tests would prove or disprove the origin of any pearl...but the labs do need the genetic material to be able to identify the pearls. I remember when I sent about a 100 vials of pearl oyster tissues to the SEEF gem lab in Basel. Then having the tissue crossing borders with letters explaining the reason to send these "biological threats" half a world away. These are costly and time-consuming tests, and I do hope they keep adding more species for analysis.
 
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