# How would the lifestyle of people change if they learned to live by doing photosynthesis?

Consider a parallel universe where people have developed into beings who can survive by doing photosynthesis. That means there is no need for food they can just survive just by using sunlight. Now consider in that universe they are same technologically advanced as us here. So how does their lifestyle or living rules changes?

Update So by lifestyle or living rules I mean in current society most of the world depends on food for surviving, people start earning to get basic necessities i.e. food, clothing and shelter with food as priority. But now since there is no need for food so how do people prioritize their actions?

Note I know the answer can be on a broader scope but I only wanted know different perspectives which you can offer.

• Hi guleria, can you enclose a little on your question? Currently it is very broad and opinion-based. How are you going to judge an answers quality? How can you determine what answers are good and which aren't? – T3 H40 Apr 29 '16 at 10:12
• Photosynthesis still needs nutrients – Erik vanDoren Apr 29 '16 at 10:37
• @guleria, could you specify in the question the basic nutrients that are still needed and their availability to the population? Just to narrow down the question a bit and, eventually, take the whole nutrient intake factor away from any answer (since I seem to understand that you want a world where "food" is something that noone would care about anymore in any way) – Erik vanDoren Apr 29 '16 at 12:11
• I'm sorry, but this just isn't possible. Even if they had solar power they would still need food, even though the sun provides energy. Because if you have some skin scraped off, if you don't eat, your body can't replace it. – Xandar The Zenon Apr 29 '16 at 12:32
• Check out Beggars In Spain by Nancy Kress. It is a sci-fi novel that dives deeply into this idea. – Henry Taylor Apr 29 '16 at 19:10

The answer to questions like this is always, "it depends."

If you are describing a sunlightarian society, based off the sub-culture who currently believe they can subsist entierly on sunlight, the single greatest focus would be on ensuring you have a sunlit area, so real-estate would be the #1 goal. Of course, they also believe that they don't need things like water or clothing. If your people also need water, that would affect the value in the real-estate market for properties close to a water source.

If you are just describing a group of people that can photosynthesize, they still need matter to build their cells with. They might, however, get really interested in composting to try to recycle their own matter. Once again, the handling of water is a question.

I think the hardest part of this question is the phrase "parallel universe." Typically such parallel universes aren't actually parallel, they're divergent. So once we no longer need to consume energy bearing matter to fuel our bodies, that is going to change how we function enough that you wouldn't recognize hardly anything at all. There would be so many changes at the genetic level that I would consider the possibility that they wouldn't even have a hominoid shape! After all, the great benefit of walking on two legs was our ability to travel remarkably long distances efficiently, in search of resources.

Hmm... i think the need for food is still there, but we will rarely need it as we can do photosynthesis.

Plants still need nutrients from the soil and air from atmosphere to breath right?

What i think is that, with photosynthesis we would last longer without food, say like a week without one and you can still function like you did last week.

We would still need water though.

As for the change though, food production won't be as top priority as much probably, but we will endeavor for it to be much more health and much more tastier. It will come to a point probably that we will consume only for "pleasure" not of "need" when it comes to that. Digestive system will probably be weaker since we don't eat as much as other animals but i could be wrong there (snakes, alligators, crocodiles comes to mind)

There're a few more questions that needs to be answered first:

How efficient is photosynthesis? Can it actually support sentient beings like us, or any animal who can, well, move around? I'm no biologist but I'm under the impression that the way Earth plants photosynthesis is far less efficient than, well, eating a bunch of stuff. Many small rodents have to eat their own body weight everyday. I don't think photosynthesis could ever be that efficient.

If your society consists of sentient beings who survive on photosynthesis, then they're probably lightly built, thin, frail creatures that don't consume much energy to move around, or move at all. And they still need large body surface to catch sunlight, so they'll probably have "wings" like bats or pterodactyls. When you figure out their physiques, then it's gonna be much easier to answer questions like, how do they move around, how to they communicate, how do they socialize/do they even need to socialize (pack mentality is irrelevant if you don't need to stay in packs to survive/hunt/etc.). That's where I'd start on worldbuilding around the idea of photosynthetic sentient beings, and chance is it's gonna be fundamentally different from our society.