When white light strikes a blue feather, the keratin pattern causes red and yellow wavelengths to cancel each other out, while blue wavelengths of light reinforce and amplify one another and reflect back to the beholder’s eye … [D]ifferent shapes and sizes of these air pockets and keratin make different shades of blue.”
There are two interesting cases of blue fish in my home state.
1. The Beardslee Trout, which exists only in a single lake in the world: https://en.wikipedia.org/wiki/Beardslee_trout. Most photos online of these fish, including the Wikipedia thumbnail, are not representative of the stunning color of these fish in person, and are most likely not Beardslees at all. The lake itself looks like blue gatorade, and the fish have obviously adapted accordingly.
2. Lingcod, a fraction of which are a crazy alien blue color not only outside but throughout the flesh. https://oregonmarinereserves.com/2021/08/31/lingcod/. This phenomenon applies to a handful of species, but lingcod is the most well-known.
The article is just trying to be controversial or something; they are actually blue. Structure colors are no less real than pigment colors. It's not an optical illusion or some glitch in human perception, bounce white light off a bluejay and pass it through a prism, a strong blue line will be apparent. That blue light really is there, therefore they really are blue.
This notion that only colors coming from pigments are true colors is completely arbitrary nonsense.
They're "true colors" but they aren't the same. Pigment colors you can generally grind up and turn into a paint, structural colors not so much. Structural colors are also often angle and polarization sensitive, not so with pigment colors.
Here’s a good answer from SE: https://biology.stackexchange.com/questions/56476/why-are-so... (spoiler: we don’t know). But the second answer speculates that blue light was the most available to the ancestors of current plants (due to properties of Earth’s atmosphere) so they evolved to absorb it.
- Blue is rare in plants since it means leaving high energy behind.
- Many animals are a color because of there food, and see above.
- Thus, any blue is trickier, and usually done via scattering and mixing rather than a pigment. "The only exception in nature is the obrina olivewing butterfly, which is the only known animal to produce a true blue pigment."
> "The only exception in nature is the obrina olivewing butterfly, which is the only known animal to produce a true blue pigment."
That is a bold claim, but a false one. A few butterfly species share that pigment. Mussels also have other blue pigments based in carothenes that don't depend on iridiscence.
Also, there is a snail that was revered millennia ago for some blue ink that could be extracted from it. Several religions, notably Judaism among them because it is still around today, attach significance to this difficult-to-obtain colour.
That's the dye from Hexaplex Trunculus, but it's more of a bluish purple than a true blue. There seems to be modern ways to turn it into a true blue, but whether the ancients had an unknown method is debated and unproven. It's worth noting that colour names in ancient times were a lot more blurry than now (the famous sea the colour of wine of Homer), and blue is still one of the most blurry.
Fascinating article. But early on I had one question - why is a blue that is made by sunlight hitting hair nanostructures considered a "simulation" thereby differentiating it from color made through sunlight interaction with biochemistry of surfaces and subsurfaces?
To draw that out further, by the same logic we might consider properties of human-made metamaterials also simulations?
I believe all of the colors of butterfly wings, and of all feathered animals are produced in the same way? I've always assumed that "simulation" has a local definition in the study of biological color reproduction, where light interactions with ultra fine structure at the atomic level is the default, or perhaps maybe on the time scale of evolution, the oldest means of reproducing color.
Contrast this witb a much coarser structural phenomenon manifesting at a level much closer to macroscopic is thus considered to be a "cheaper" simulation of that effect, in order to derive its same selective benefits but with less of a radical genetic shift required for the production of the right proteins etc.
The article says "manipulate the light that shines on them that simulates their signature blue look". https://en.wiktionary.org/wiki/simulation meaning number 4, "Assuming an appearance which is feigned, or not true.".
I believe what they are trying to communicate (pretty poorly) is that the hairs are not blue as such, but in certain circumstances can manipulate light into the blue-violet spectrum.
Think of it this way: a prism isn't any of the rainbow colors, but can manipulate light into such.
As for animals, they need to avoid predators. I'd say that blue isn't the best color to hide in most areas. So selection should favor other colors, unless the color is used as a warning, e.g. to signal a poisonous creature.
"...once Nakamura succeeded in creating a commercially viable prototype, 3 orders of magnitude (1000 times) brighter than previously successful blue LEDs, Nichia pursued developing the marketable product. The company's gross receipt surged from just over ¥20 billion (≈US$200 million) in 1993 to ¥80 billion (≈US$800 million) by 2001, 60 percent of which was accounted for by sales of blue LED products."
And IIRC, in return for that he got a $180 bonus from his employer, and a bit later, a Nobel prize.
>Organisms that appear blue must absorb very small amounts of energy, while reflecting high-energy blue light. Since penetrating the molecules that are capable of absorbing this energy is a complex process, the color blue is less common than other colors in the natural world.
I’m not a biologist, but these sentences immediately reminded me of reading articles about my company/technology after press briefings and feeling like they butchered a basic concept (or more correctly, I failed to explain it in an accessible way). Like, the sentences are grammatically correct but don’t make technical sense.
You’re not wrong. It appears to be a very garbled technical explanation. Mainly that organisms need to absorb low frequency/energy light while reflecting higher frequency/energy light. I’m guessing that chemically that’s harder to do.
Molecules that appear blue must absorb very small amounts of energy, while reflecting high-energy blue light. Since assembling the molecules that are capable of absorbing this energy is a complex process, the color blue is less common than other colors in the natural world.
Plants are green(On earth) because they reflect the green color (which the sun spectrum is strongest) because they have probably adapted to better regulate different lightning condition during the day, for this they use two different pigments (chlorophyll a(blue), chlorophyll b(red); or other pairs)
Exactly; see pollinators comment above. Although as tech progresses... perhaps we can make black plants as attractive to genetically modified pollinators. Do I sense a slippery slope here?
That will only be the case if light absorbence is the primary limiting factor for the plant. If something else is a bigger limiting factor (e.g., nutrients, pests, water, temperature, pollinators, and so on), then a more darkly colored plant will not be meaningfully more likely to survive and reproduce than its lightly colored neighbors.
Outside of human-directed breeding, we typically only see darkly colored plants in locations with low light and with few other evolutionary pressures: deep understory tropical plants, for example.
Meanwhile, in locations with high light and other evolutionary pressures, plants can sometimes evolve to be quite pale. For example, desert succulents are often very light colors because they need to deflect light to keep cool and preserve water.
I honestly doubt it’s in a global optimum, as evolution is easily stuck in decent local minima.
Simple example: “C4 carbon fixation”, which allows photosynthesis to proceed with much less water available, only evolved ~30 million years ago. This was the revolution that allowed modern grasses to emerge, and thus changed enormous barren deserts into the savannahs that early humans made their home. Despite being such an improvement, this is not yet a “standard”; trees, for example, still use the “old” inefficient “C3 carbon fixation”.
Despite photosynthesis having been around for hundreds of millions of years, fundamental improvements still happened just 30 million years ago. I would suspect that there is more that can still be improved.
To be fair, indigo is a blue pigment and it is present in many different plant species. (Mind you, it does not make the plant blue; it only becomes blue after exposure to oxygen.)
Are blue animals rare? They are certainly not that rare as a casual search turns up hundreds of photos of blue lizards, butterflies, Beatles, spiders, birds, starfish, fish, whales, sharks, and other miscellaneous sea and land creatures.
there are very few blue colored animals. also it was very difficult to develop LEDs emitting blue colored light. are those two observations technically related? can you summarize the technical relationship in a paragraph of few sentences?
answer:
The rarity of blue color in animals and the difficulty in developing blue LEDs are technically related due to the higher energy associated with blue light. Producing materials or structures that can efficiently emit or reflect blue light is challenging because blue light has shorter wavelengths and higher energy, requiring precise and stable materials. In animals, this results in the reliance on complex structural coloration rather than pigments. Similarly, the development of blue LEDs required breakthroughs in materials science to create stable semiconductors capable of emitting high-energy blue light, such as gallium nitride.
I never gave this much thought before but the book quite successfully managed to interest me in its subject and lead to me understanding some of the underlying mechanisms (which lay all outside my domain as a software developer).
70 comments
[ 4.0 ms ] story [ 142 ms ] threadWeird that this website seems broken with an un dismissable popup on an iphone… not exactly a rare user device.
Chicory has nice blue flowers.
Both are common in Chicagoland.
[1] https://blog.education.nationalgeographic.org/2016/05/09/the...
When white light strikes a blue feather, the keratin pattern causes red and yellow wavelengths to cancel each other out, while blue wavelengths of light reinforce and amplify one another and reflect back to the beholder’s eye … [D]ifferent shapes and sizes of these air pockets and keratin make different shades of blue.”
IIRC, the vast majority of bees are solitary (90%?)
Lots of fish, dolphins, whales, etc. Or do they count as grey?
1. The Beardslee Trout, which exists only in a single lake in the world: https://en.wikipedia.org/wiki/Beardslee_trout. Most photos online of these fish, including the Wikipedia thumbnail, are not representative of the stunning color of these fish in person, and are most likely not Beardslees at all. The lake itself looks like blue gatorade, and the fish have obviously adapted accordingly.
2. Lingcod, a fraction of which are a crazy alien blue color not only outside but throughout the flesh. https://oregonmarinereserves.com/2021/08/31/lingcod/. This phenomenon applies to a handful of species, but lingcod is the most well-known.
Also plenty of birds are blue are they not?
And I totally forgot about butterflies and other insects as well
If you add an acid to it (like lemon or lime) it turns to the beautiful purple colour you see on the right.
But I think there may be a joke going over my head here...
I stand corrected
The article is just trying to be controversial or something; they are actually blue. Structure colors are no less real than pigment colors. It's not an optical illusion or some glitch in human perception, bounce white light off a bluejay and pass it through a prism, a strong blue line will be apparent. That blue light really is there, therefore they really are blue.
This notion that only colors coming from pigments are true colors is completely arbitrary nonsense.
https://duckduckgo.com/?t=h_&q=Dendrobates+Tinctorius+Azureu...
https://www.reddit.com/r/todayilearned/comments/5dg5qs/til_t...
Related question is why plants are green: https://biology.stackexchange.com/questions/450/why-do-plant...
Basically:
- Blue is rare in plants since it means leaving high energy behind.
- Many animals are a color because of there food, and see above.
- Thus, any blue is trickier, and usually done via scattering and mixing rather than a pigment. "The only exception in nature is the obrina olivewing butterfly, which is the only known animal to produce a true blue pigment."
That is a bold claim, but a false one. A few butterfly species share that pigment. Mussels also have other blue pigments based in carothenes that don't depend on iridiscence.
[Centaurea cyanus](https://en.wikipedia.org/wiki/Centaurea_cyanus?wprov=sfla1)
[Digitalis](https://en.wikipedia.org/wiki/Digitalis?wprov=sfla1)
[Centaurea](https://en.wikipedia.org/wiki/Centaurea?wprov=sfla1)
[Scabiosa](https://en.wikipedia.org/wiki/Scabiosa?wprov=sfla1)
[Phacelia](https://en.wikipedia.org/wiki/Phacelia?wprov=sfla1)
and last but not least many varieties of [Campanula](https://en.wikipedia.org/wiki/Campanula?wprov=sfla1)
I could offer
[Chicory](https://en.wikipedia.org/wiki/Chicory?wprov=sfla1), [Myosotis](https://en.wikipedia.org/wiki/Myosotis?wprov=sfla1) and [Borage](https://en.wikipedia.org/wiki/Borage?wprov=sfla1)
as replacements ...
They are made to stand out, so it is like they are a purposeful exception to the rule
I am pretty sure that they were referring to the plant itself being blue (like leaves and stems), not the flowers.
To draw that out further, by the same logic we might consider properties of human-made metamaterials also simulations?
Contrast this witb a much coarser structural phenomenon manifesting at a level much closer to macroscopic is thus considered to be a "cheaper" simulation of that effect, in order to derive its same selective benefits but with less of a radical genetic shift required for the production of the right proteins etc.
I believe what they are trying to communicate (pretty poorly) is that the hairs are not blue as such, but in certain circumstances can manipulate light into the blue-violet spectrum.
Think of it this way: a prism isn't any of the rainbow colors, but can manipulate light into such.
https://youtube.com/watch?v=AF8d72mA41M
And IIRC, in return for that he got a $180 bonus from his employer, and a bit later, a Nobel prize.
I’m not a biologist, but these sentences immediately reminded me of reading articles about my company/technology after press briefings and feeling like they butchered a basic concept (or more correctly, I failed to explain it in an accessible way). Like, the sentences are grammatically correct but don’t make technical sense.
Molecules that appear blue must absorb very small amounts of energy, while reflecting high-energy blue light. Since assembling the molecules that are capable of absorbing this energy is a complex process, the color blue is less common than other colors in the natural world.
Plants are green(On earth) because they reflect the green color (which the sun spectrum is strongest) because they have probably adapted to better regulate different lightning condition during the day, for this they use two different pigments (chlorophyll a(blue), chlorophyll b(red); or other pairs)
Outside of human-directed breeding, we typically only see darkly colored plants in locations with low light and with few other evolutionary pressures: deep understory tropical plants, for example.
Meanwhile, in locations with high light and other evolutionary pressures, plants can sometimes evolve to be quite pale. For example, desert succulents are often very light colors because they need to deflect light to keep cool and preserve water.
Simple example: “C4 carbon fixation”, which allows photosynthesis to proceed with much less water available, only evolved ~30 million years ago. This was the revolution that allowed modern grasses to emerge, and thus changed enormous barren deserts into the savannahs that early humans made their home. Despite being such an improvement, this is not yet a “standard”; trees, for example, still use the “old” inefficient “C3 carbon fixation”.
Despite photosynthesis having been around for hundreds of millions of years, fundamental improvements still happened just 30 million years ago. I would suspect that there is more that can still be improved.
and the pH sensitive stuff in red cabbage juice.
After their death, the yellow pigments fade, leaving a blue husk of a snake.
there are very few blue colored animals. also it was very difficult to develop LEDs emitting blue colored light. are those two observations technically related? can you summarize the technical relationship in a paragraph of few sentences?
answer:
The rarity of blue color in animals and the difficulty in developing blue LEDs are technically related due to the higher energy associated with blue light. Producing materials or structures that can efficiently emit or reflect blue light is challenging because blue light has shorter wavelengths and higher energy, requiring precise and stable materials. In animals, this results in the reliance on complex structural coloration rather than pigments. Similarly, the development of blue LEDs required breakthroughs in materials science to create stable semiconductors capable of emitting high-energy blue light, such as gallium nitride.
I never gave this much thought before but the book quite successfully managed to interest me in its subject and lead to me understanding some of the underlying mechanisms (which lay all outside my domain as a software developer).
“Why Trout Is Turning Blue in an Old Garage in Queens”
It’s the best way to cook trout. You’re welcome.
https://www.vice.com/en/article/kbxdv9/why-trout-is-turning-...