The sources I found disagree, but seem to also provide 8-9% as the more realistic higher end whilst 12% or so is the theoretical maximum. Using the lower of the two higher end realistic values for an earth like world’s flora’s photosynthetic efficiency we can plug 8% into the equation provided earlier by hhyrlylainen.
340 * 0.08 = 27.2
100 / 27.2 = 3.67647058824
Yikes. Still not the best considering that’s nearly double the surface area of an adult male human (1.9m^2)
So what about if we plug in the theoretical maximum instead?
340 * 0.12 = 40.8
100 / 40.8 = 2.45098039216
And that looks a lot better, seeing as that is only %128.998968008 of the surface area of a human, and the photosynthetic surfaces could probably also serve as an equivalent to skin.
Anyway, so theoretically possible? Maybe. Probable? Unlikely. I can think of a couple possibilities for how it could evolve a brain though presuming it can even be done, and also a method of reducing the immediate power requirement of the early brain prior to developing humanlike intelligence: Human brains did not appear overnight, but evolved slowly, and there exist many smaller designs for brains used by less intelligent organisms which would most likely be cheaper as an intermediary option.
Additionally, certain trees can in fact possibly move. Socratea exorrhiza exists. Although certainty on that one is dubious.
Edit:
And as for why a brain would be useful, defense. Can’t be eaten by herbivores as easily if you can defend yourself.
Please do not double post. In your second post you did already find out how to edit posts.
I’ll combine your posts myself this time.
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Deathwake
(i nuked zenzone and will never let him forget it)
37
I think the most probable way a photosynthetic “critter” could come about is as a fruiting body that wanders until it detects good soil quality and few competitors. They would most likely have high:protein, high fiber tissues attached to a sort of acorn like cap for structural support. They’d move like Kirby and probably evolve over time to have brains. From there it’s speculative nonsense as as opposed to speculative semi-sense but I think it’s possible for them to develop ways for the information stored in the brain to be passed on from fruiting body to stationary plant to next generation or fruiting body. Intelligence cod evolve as millions of years of experience searching for good spots, living in said spots, and avoiding predators would make for very smart creatures. They obviously couldn’t store millions of years of memories but they’d keep all the skills and any life lessons. I have no idea why such a creature would develop tool use, perhaps fruiting bodies would travel in groups and some would grow while others defended the saplings until the oldest saplings could make more fruiting bodies and the cycle could repeat? In a setting like that stick or stone walls, or pit traps or spears are all viable, but I don’t see how that would work. Honestly the only viable plant civs in my mind are the piggies from speaker for the dead.
So you are bringing in the point that we could potentially see plants which take on a secondary role as detritivores followed by a gradual transition in which the supplementary source of sustenance becomes progressively more important as the original is simultaneously phased out? As this happens, it loses the ability to be completely an autotroph whilst retaining photosynthetic capabilities as a supplement?
Almost - not exactly a detrivore like worms - think more like scavengers, flies and buzzards. These plants would dig through the soil a little for food and nutrients, but gather most of what they need from carcasses.
Also, not so much they lose their ability to synthesize - just that it would no longer be the only source of energy they need to survive (and so I try to fix the lack of caloric intake issue)
are you talking about c3 or c4 because with c3 efficiency is 4.6% whereas in c4 it is up to 6% and when stomata are closed if not what kind of photosynthesis are you talking about
I frankly don’t care, I’m just trying to prevent the game from becoming terrible with unrealistic things being suggested to be added. I’d really prefer if our theory team was more active and was able to torpedo really terrible suggestions like this thread instead of me having to do this with my limited understanding.
to sustain a hollow boned human with just photosynthesis for a couple months with no food just use two relatively flat butterfly type 4 foot long 3 foot tall wings on a planet with low gravity and a dense atmosphere
Also, if it isn’t required, not having it would be selected.
Corals are like a single photosynthetic creature. The animal part keeps the algea from drifting away to darkness. Chloroplast stealers use the chloroplasts as long as they last. It is as if photosynthesising in addition to eating other plants is nice, but using your own resources to build chloroplasts or carrying the gene for building it in all of your cells isn’t worth it.
But the exclusive herbivores would be lighter (not carrying a wing to increase surface area) and outrun the part-time-herbivore/part-time-photosynthesisers. The evolutionary arms race would end in the part time photosynthesiser giving up on running and focusing on building an impenetrable castle, which is constantly being supplied from above. And no tools can be used without movement.
I’ll exit this discussion now for my sanity, and unless another team member participates in this discussion as the opposing voice, winning by “silencing” the opposition doesn’t count.
I don’t know if anyone has said this yet, but maybe fungal (Earth fungi specifically) organisms that are similar to animals could use a matrix of mycelium like a brain?
Also, plants do have some intelligence, and they certainly have senses and can communicate with each other, but their intelligence is limited due to the lack of a centralized nervous system.