The sun is green and plants used to be purple.

I've wondered for a while why our eyes evolved to be most sensitive to green - and why camera manufacturers optimize for green (twice as many green pixels on a Bayer sensor than red or blue).

Obviously plants being green is a big part of it, but then why are plants green? That is - why does photosynthesis happen in the range that it does.

Apparently - the sun emits the most energy in the green spectrum, but plants have evolved to ignore it absorbing blue and red energy instead, which is why they reflect back green.

One wonders if those two factors were what caused evolution to favor green for light detection. (Other animals of course have more or different colors they perceive.)

IDK if anyone else likes geeking out on these topics but I find them fascinating.

Nature uses what’s available on hand, and typically uses only what’s been used before.



For example, nature doesn’t use internal combustion, or metal above the molecular level.

saltydogstudios said:

I've wondered for a while why our eyes evolved to be most sensitive to green -

Click to expand...

My take is that our ancient ancestors while still basically living in the trees, needed good green seeing ability to more easily differentiate between different food sources.

The guys who didn't sort out their greens accurately probably ate something poisonous and thus died out. Darwin theory at work.

In biology, the three color receptor cells in put eyes are labeled "high", "mid", and "low". The boundaries of the "low" and "high" are easily given by the simple fact that air is translucent in this range. Go much lower, and (some) solids become transparent, go much higher, and water (vapor) becomes opaque.

The "middle" of the visible spectrum is where most of the energy is, hence where photosynthesis is most effective. It's therefore also where most brightness comes from, and it is extremely abundant in nature. Consequently, we have two receptors, "low" and "mid", which overlap strongly in this area, to give us as much contrast as possible in this area.

What I find interesting is that our three receptors give us a scalar perception of color. We see each object having a single, unique color, even though light itself is a spectrum. Like audio, where sounds can be composed of many frequencies, so light is as well. But we perceive it not as a mixture, but as a single value. And we perceive color as circular, not linear, even though light clearly has high and low frequencies (the trick being that we label the mixture of high and low "magenta", the only color that does not look like any single wavelength).

We are odd creatures, and perceive things in odd ways.

Guy Parsons said:

saltydogstudios said:

I've wondered for a while why our eyes evolved to be most sensitive to green -

Click to expand...

My take is that our ancient ancestors while still basically living in the trees, needed good green seeing ability to more easily differentiate between different food sources.

The guys who didn't sort out their greens accurately probably ate something poisonous and thus died out. Darwin theory at work.

Click to expand...

That's my basic understanding as well, though "eyes" probably evolved multiple times in multiple species and underwater species were likely a big part of it.

But simplistically, yes - being able to see green was the most important thing. Then being able to see subtleties (adding red) so - animals and fruit stood out - was important.

I suspect - just a gut feeling not informed by research - is that's also the reason blue is weaker and further away is that it came along later.

bastibe said:

In biology, the three color receptor cells in put eyes are labeled "high", "mid", and "low". The boundaries of the "low" and "high" are easily given by the simple fact that air is translucent in this range. Go much lower, and (some) solids become transparent, go much higher, and water (vapor) becomes opaque.

Click to expand...

Sure - I think anyone who works with infrared cameras understands some solids becoming transparent - being able to see veins under skin, for example. Some medical machinery uses this specifically.

Interesting about water vapor becoming opaque. It sounds like our eyes are well optimized for our environment. Liquid water being opaque would be basically useless if you were a fish.

bastibe said:

The "middle" of the visible spectrum is where most of the energy is, hence where photosynthesis is most effective. It's therefore also where most brightness comes from, and it is extremely abundant in nature. Consequently, we have two receptors, "low" and "mid", which overlap strongly in this area, to give us as much contrast as possible in this area.

What I find interesting is that our three receptors give us a scalar perception of color. We see each object having a single, unique color, even though light itself is a spectrum. Like audio, where sounds can be composed of many frequencies, so light is as well. But we perceive it not as a mixture, but as a single value. And we perceive color as circular, not linear, even though light clearly has high and low frequencies (the trick being that we label the mixture of high and low "magenta", the only color that does not look like any single wavelength).

We are odd creatures, and perceive things in odd ways.

Click to expand...

We are just brains in a vat driving meat machines... What fascinates me is how - for the purely functional task of understanding what food is nutritions - we have such a strong experience of flavor.

As much as we like to think humans have "intelligence" and our perception of reality shouldn't necessarily be flavored (pun intended) by subjective experience, nature figured out a way to ensure every species enjoys the taste of food.

saltydogstudios said:

Guy Parsons said:

saltydogstudios said:

I've wondered for a while why our eyes evolved to be most sensitive to green -

Click to expand...

My take is that our ancient ancestors while still basically living in the trees, needed good green seeing ability to more easily differentiate between different food sources.

The guys who didn't sort out their greens accurately probably ate something poisonous and thus died out. Darwin theory at work.

Click to expand...

That's my basic understanding as well, though "eyes" probably evolved multiple times in multiple species and underwater species were likely a big part of it.

But simplistically, yes - being able to see green was the most important thing. Then being able to see subtleties (adding red) so - animals and fruit stood out - was important.

I suspect - just a gut feeling not informed by research - is that's also the reason blue is weaker and further away is that it came along later.

Click to expand...

Well, I am glad we evolved the way we did, because red or blue grass would be really annoying.

Mackiesback said:

saltydogstudios said:

Guy Parsons said:

saltydogstudios said:

I've wondered for a while why our eyes evolved to be most sensitive to green -

Click to expand...

My take is that our ancient ancestors while still basically living in the trees, needed good green seeing ability to more easily differentiate between different food sources.

The guys who didn't sort out their greens accurately probably ate something poisonous and thus died out. Darwin theory at work.

Click to expand...

That's my basic understanding as well, though "eyes" probably evolved multiple times in multiple species and underwater species were likely a big part of it.

But simplistically, yes - being able to see green was the most important thing. Then being able to see subtleties (adding red) so - animals and fruit stood out - was important.

I suspect - just a gut feeling not informed by research - is that's also the reason blue is weaker and further away is that it came along later.

Click to expand...

Well, I am glad we evolved the way we did, because red or blue grass would be really annoying.

Click to expand...

Homer thought the sea was red

https://en.wikipedia.org/wiki/Wine-dark_sea_(Homer)

Mark S Abeln said:

Nature uses what’s available on hand, and typically uses only what’s been used before.

For example, nature doesn’t use internal combustion, or metal above the molecular level.

--
http://therefractedlight.blogspot.com

Click to expand...

No, nature doesn't "do" anything. It's not a being.

Evolution means that failure doesn't succeed. Or course, humans have messed up that part.

Anthropomorphism is disrespectful.

PhotoMac503 said:

No, nature doesn't "do" anything. It's not a being.

Click to expand...

...

PhotoMac503 said:

Anthropomorphism is disrespectful.

Click to expand...

To whom is it disrespectful?

Guy Parsons said:

saltydogstudios said:

I've wondered for a while why our eyes evolved to be most sensitive to green -

Click to expand...

My take is that our ancient ancestors while still basically living in the trees, needed good green seeing ability to more easily differentiate between different food sources.

The guys who didn't sort out their greens accurately probably ate something poisonous and thus died out. Darwin theory at work.

Click to expand...

I recently saw on a nature program where they said some animals that are the prey of large cats can't distinguish between green and orange. Thus, tigers being orange isn't a problem, as they hunt antelope or whatever. But we can see the orange. We may not be as sensitive with colors other than green, but enough to have a better chance at survival, and maybe that was good enough.

Mark S Abeln said:

PhotoMac503 said:

No, nature doesn't "do" anything. It's not a being.

Click to expand...

...

Mark S Abeln said:

Anthropomorphism is disrespectful.

Click to expand...

To whom is it disrespectful?

Click to expand...

maybe to the anthropoids?

nature certainly doesn’t care

saltydogstudios said:

Mark S Abeln said:

PhotoMac503 said:

No, nature doesn't "do" anything. It's not a being.

Click to expand...

...

saltydogstudios said:

Anthropomorphism is disrespectful.

Click to expand...

To whom is it disrespectful?

Click to expand...

maybe to the anthropoids?

nature certainly doesn’t care

Click to expand...

Yup, we humans are simply the totally accidental product of some stars a long time ago blowing themselves to bits and scattering their newly formed elements helter-skelter throughout the galaxy.

The concept of "Nature" is also some accidental product of that and is not some entity we can identify with.

The usual explanation promoted for color vision in primates is it enables being able to tell if fruit is ripe or not. Predators don't need to tell if fruit is ripe, so they don't have color vision.

I am not sure where I picked that up.... probably in an optometry or ophthalmology textbook as I have read a lot of them. But I have not read any books on evolutionary biology, so if someone came along with a deeper insight, I would defer to them.

OpticsEngineer said:

The usual explanation promoted for color vision in primates is it enables being able to tell if fruit is ripe or not. Predators don't need to tell if fruit is ripe, so they don't have color vision.

Click to expand...

I’ve read that too. There is strong overlap between the L and M (“red” and “green”) cone sensitivity. They think that one of those cone types is a genetic mutation from the other.

While there is a strong overlap, the calculus first derivative of responses with regards to frequency is very different with both. Slight changes in frequency leads to significantly different responses. This is relevant to camera color filter arrays as well.

This is not only significant for ripening fruit, but human skin hue also falls in this range, with far-ranging consequences.

OpticsEngineer said:

I am not sure where I picked that up.... probably in an optometry or ophthalmology textbook as I have read a lot of them. But I have not read any books on evolutionary biology, so if someone came along with a deeper insight, I would defer to them.

Click to expand...

I don’t recall where I read it either.

Every colo(u)r you can see is in a sunbeam. There are also a lot that you can't see.

You have to make an effort to separate them.

saltydogstudios said:

Mackiesback said:

saltydogstudios said:

Guy Parsons said:

saltydogstudios said:

I've wondered for a while why our eyes evolved to be most sensitive to green -

Click to expand...

My take is that our ancient ancestors while still basically living in the trees, needed good green seeing ability to more easily differentiate between different food sources.

The guys who didn't sort out their greens accurately probably ate something poisonous and thus died out. Darwin theory at work.

Click to expand...

That's my basic understanding as well, though "eyes" probably evolved multiple times in multiple species and underwater species were likely a big part of it.

But simplistically, yes - being able to see green was the most important thing. Then being able to see subtleties (adding red) so - animals and fruit stood out - was important.

I suspect - just a gut feeling not informed by research - is that's also the reason blue is weaker and further away is that it came along later.

Click to expand...

Well, I am glad we evolved the way we did, because red or blue grass would be really annoying.

Click to expand...

Homer thought the sea was red

https://en.wikipedia.org/wiki/Wine-dark_sea_(Homer)

Click to expand...

I think this refers to luminance rather than hue.

Don

Guy Parsons said:

saltydogstudios said:

Mark S Abeln said:

PhotoMac503 said:

No, nature doesn't "do" anything. It's not a being.

Click to expand...

...

Guy Parsons said:

Anthropomorphism is disrespectful.

Click to expand...

To whom is it disrespectful?

Click to expand...

maybe to the anthropoids?

nature certainly doesn’t care

Click to expand...

Yup, we humans are simply the totally accidental product of some stars a long time ago blowing themselves to bits and scattering their newly formed elements helter-skelter throughout the galaxy.

Click to expand...

I would say "inevitable" rather than accidental. Given enough planets with suitable temperature, gravity, etc, complex organic molecules are bound to appear somewhere.

Guy Parsons said:

The concept of "Nature" is also some accidental product of that and is not some entity we can identify with.

Click to expand...

OpticsEngineer said:

The usual explanation promoted for color vision in primates is it enables being able to tell if fruit is ripe or not. Predators don't need to tell if fruit is ripe, so they don't have color vision.

Click to expand...

Naturalists and Biologists come up with a lot of hypothetical "reasons" for things and often start whole branches of specialties from them.

Sometimes these are ludicrously and terribly wrong.

There were a host of pseudo sciences that arose from Darwin's "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life."

Phrenology and Eugenics come immediately to mind and were used to support the concept of race and racial superiority, continuation of slavery, hereditary monarchies, social classes, and the famous 'Master Race' of WW II.

It's a good thing we will soon have AI to sort through all this nonsense and just give us facts from the cloud!

Isn't it??

--
I'm a photographer, Jim, not a graphic artist!
My photo blog: http://birdsnbugs.com
RF Stock Portfolio - http://www.dreamstime.com/resp129611

BGD300V1 said:

OpticsEngineer said:

The usual explanation promoted for color vision in primates is it enables being able to tell if fruit is ripe or not. Predators don't need to tell if fruit is ripe, so they don't have color vision.

Click to expand...

Naturalists and Biologists come up with a lot of hypothetical "reasons" for things and often start whole branches of specialties from them.

Sometimes these are ludicrously and terribly wrong.

There were a host of pseudo sciences that arose from Darwin's "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life."

Phrenology and Eugenics come immediately to mind and were used to support the concept of race and racial superiority, continuation of slavery, hereditary monarchies, social classes, and the famous 'Master Race' of WW II.

It's a good thing we will soon have AI to sort through all this nonsense and just give us facts from the cloud!

Isn't it??

Click to expand...

You forgot to add the quote marks around the word "facts".