# Why did plants evolve to be green? **URL:** \ **Category:** Factual Questions\ **Created:** [August 6, 2022, 7:28am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180 "2022-08-06T07:28:24Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![SmartBulbInc](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@SmartBulbInc](https://boards.straightdope.com/u/SmartBulbInc)\ **Post date:** [August 6, 2022, 7:28am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/1 "2022-08-06T07:28:24Z")
I chemically why plants are green: they are green because of chlorophyll. But, my question is why did plants evolve that way in the first place? What sort of advantage would early plants have to become green over any other color? ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [August 6, 2022, 8:10am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/2 "2022-08-06T08:10:26Z")
The advantage of chlorophyll is that a plant can create more food. Plants that were better able to produce chlorophyll must have had a competitive advantage. It isn’t any more complex than that (unless I’m misunderstanding your question) ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [August 6, 2022, 8:25am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/3 "2022-08-06T08:25:45Z")
If I understand your question correctly, the book "[Eating the Sun: How Plants Power the Planet"](https://www.amazon.de/Eating-Sun-Plants-Power-Planet/dp/0007163657) would be of interest to you. I remember enjoying it. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [August 6, 2022, 8:50am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/4 "2022-08-06T08:50:07Z")
I _wanna_ say I have a vague memory that wavelengths in what we perceive as “green” carry the most energy? or that it’s easier to convert to energy? But again, the vaguest of vague guesses. Taking a stab that this might possibly hold a clue to the answer (or knowing this place, generate some weird hijack) but keep in mind that plants have lots of other pigments. That’s why we see brilliant autumn colors - the pigments that were always there anyway are no longer masked by the chlorophyll and are now visible. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [August 6, 2022, 9:00am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/5 "2022-08-06T09:00:29Z")
Pretty sure that is correct. The color is best to absorb the sunlight energy. But it is not really the color of the plant. It is the reflected color. So not the color wavelength it is best absorbing. Kind of an awkward way to say it. ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [August 6, 2022, 9:47am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/6 "2022-08-06T09:47:55Z")
There are numerous plants that are not green, or not entirely green. I am sitting in a garden with quite a few plants that are not green; some of which, but by no means all, have been bred for variagation, colour, etc. These are all succulents indigenous to parts of Southern Africa: > **[20220806-113454 hosted at ImgBB](https://ibb.co/bFYySzJ)** > > Image 20220806-113454 hosted in ImgBB > **[20220806-113443 hosted at ImgBB](https://ibb.co/mF21BbH)** > > Image 20220806-113443 hosted in ImgBB > **[20220806-113419 hosted at ImgBB](https://ibb.co/TTFrbSL)** > > Image 20220806-113419 hosted in ImgBB The red plants have chlorophyll that absorbs the red and blue light, but also have red anthocyanins, probably to protect the plant from the harsh summer sun (these plants typically originate in scrub desert). ETA… sorry about the excessively ad-filled pages those pictures are hosted on ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [August 6, 2022, 9:49am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/7 "2022-08-06T09:49:53Z")
Chlorophyll reflects the green wavelengths of light, hence, plants are green. They actually use other light wave lengths to photosynthesize, not the green ones. Chlorophyll is not the only pigment used in photosynthesis. [See here.](https://www.biosciencenotes.com/photosynthetic-pigments/) Some are present in sufficient abundance to change the color of the plant, which is why red algae are red (they still use green chlorophyll for photosynthesis). Some plants have a lot of these pigments that can be protective against _too much_ sunlight. As to why green plants dominate… well, they’re the ones that won the evolutionary contest. ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [August 6, 2022, 9:58am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/8 "2022-08-06T09:58:19Z")
As a slight aside, I once attended a church service where the priest suggested that because scientists had found that the most calming colour is green, and nature is mostly green… therefore god! Even to my 11 year old mind this reasoning seemed a little faulty. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [August 6, 2022, 12:16pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/9 "2022-08-06T12:16:57Z")
> [@scudsucker](#): > > ETA… sorry about the excessively ad-filled pages those pictures are hosted on If you right-click on an image and select “open image”, it should isolate the picture in its own page. Copy the url, and paste it: [![](https://i.ibb.co/m0dYL68/20220806-113454.jpg) ](https://i.ibb.co/m0dYL68/20220806-113454.jpg) ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 6, 2022, 12:50pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/10 "2022-08-06T12:50:52Z")
Earth’s early conditions changed as a result of blue-green algae and other colors first changing the conditions of the atmosphere and water before green algae developed and dominated. I’m not quite old enough to have been there so perhaps someone older or who has studied the subject could fill in the details. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [August 6, 2022, 1:20pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/11 "2022-08-06T13:20:13Z")
> [@SmartBulbInc](#): > > What sort of advantage would early plants have to become green over any other color? None. The bacteria first evolved solar power ( I mean , using light photons to provide energy… ) for various reasons … and not to make them green or chlorophylls photosynthesis… the solar power system evolves into chlorophyll later… Plants get the genetic material from bacteria … they seem to have included the bacteria lock stock and barrel into the plant cell… as chloroplasts in the cell… like a mitochondria in your cells … “While we often talk about the evolution of photosynthesis as if it were a concerted process, it is more useful to consider the evolution of various photosynthetic subsystems, which have clearly had distinct evolutionary trajectories. In this brief review we will discuss the evolution of photosynthetic pigments, reaction centers (RCs), light-harvesting (LH) antenna systems, electron transport pathways, and carbon fixation pathways. These subsystems clearly interact with each other, for example both the RCs and antenna systems utilize pigments, and the electron transport chains interact with both the RCs and the carbon fixation pathways. However, to a significant degree they can be considered as modules that can be analyzed individually.” See [Early Evolution of Photosynthesis - PMC](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2949000/) ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [August 6, 2022, 1:32pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/12 "2022-08-06T13:32:22Z")
As for why chlorophyll has settled on green … well he reckons its due to the better utility of the red and blue light. 1. just the right photon energy and power of light 2. the steep edge of the spectrum helps limit the power absorbed. It COULD absorb from frequencies A to C, but because of the step slope of the spectrum at B, in sunlight its only absorbing from B to C… So its doing that to limit the power ? see > **[Why Are Plants Green? To Reduce the Noise in Photosynthesis.](https://www.quantamagazine.org/why-are-plants-green-to-reduce-the-noise-in-photosynthesis-20200730/)** > > Plants ignore the most energy-rich part of sunlight because stability matters more than efficiency, according to a new model of photosynthesis. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 6, 2022, 1:51pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/13 "2022-08-06T13:51:31Z")
> [@purplehorseshoe](#): > > I _wanna_ say I have a vague memory that wavelengths in what we perceive as “green” carry the most energy? or that it’s easier to convert to energy? Yes, which is precisely why it’s surprising that chlorophyll is green. The color we see to a substance is the wavelengths that it’s not absorbing. As for why, all of the other pigments used in photosynthesis, despite their more favorable colors, are less efficient for other reasons. It’s probably chemically possible to have a pigment that doesn’t have those other reasons, and is even more efficient than chlorophyll by virtue of having a better color, but that other pigment just happened to never in the planet’s history see a mutation that produced it, and so natural selection never got a chance to work on it. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 6, 2022, 2:14pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/14 "2022-08-06T14:14:27Z")
There’s a bit of debate about this, but it seems likely that the Earth was purple before it was green. A lot of researchers believe that most early plants and photosynthetic microbes were based on retinal instead of chlorophyll. Over time, chlorophyll based plants eventually won the evolutionary race, and the world changed from purple to green. The link that @Isilder provided above is the first time that I have seen a decent explanation about why chlorophyll won out over retinal (basically, stability beat efficiency). ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [August 6, 2022, 3:09pm UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/15 "2022-08-06T15:09:04Z")
> [@scudsucker](#): > > As a slight aside, I once attended a church service where the priest suggested that because scientists had found that the most calming colour is green, and nature is mostly green… therefore god! > > Even to my 11 year old mind this reasoning seemed a little faulty. That was something that was also told to a young Christopher Hitchens (clearly it used to be a theological stock answer) and he too found that sadly lacking as an answer. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 7, 2022, 1:55am UTC](https://boards.straightdope.com/t/why-did-plants-evolve-to-be-green/969180/16 "2022-08-07T01:55:42Z")
There’s also this major event in the biosphere’s history: > **[Great Oxidation Event](https://en.wikipedia.org/wiki/Great_Oxidation_Event)** > > The Great Oxidation Event (GOE), also called the Great Oxygenation Event, the Oxygen Catastrophe, the Oxygen Revolution, the Oxygen Crisis, or the Oxygen Holocaust, was a time interval during the Paleoproterozoic era when the Earth's atmosphere and the shallow ocean first experienced a rise in the amount of oxygen. This began approximately 2.460–2.426 Ga (billion years) ago, during the Siderian period, and ended approximately 2.060 Ga, during the Rhyacian. Geological, isotopic, and chem The su...