Could an autotrophic civilisation develop, or will evolving life forms always eat each other?

I can imagine our own civilisation becoming autotrophic eventually, if biological life gives way to a population of machines that need only sunlight. However, the history of that situation still involved a long period of organic life forms eating each other.

So my question is about an organic evolutionary history with only autotrophic organisms, that still leads to civilisation.

I'm imagining a world in which organic life forms evolve to gain energy from light/other radiation/heat/chemicals in the environment without any of them ever evolving to gain energy from eating other life forms. That is, an entire evolutionary history without any of the life forms eating others.

I see two potential obstacles to this:

• Without the increased complexity of competition involved with eating and being eaten, and the far higher energy density available, intelligence may never emerge.
• Even if the emergence of intelligence is possible that way, it may be impossible to have a large varied population without the spontaneous emergence of organisms that eat others.

I'd like to know if there are natural situations in which these two obstacles would not apply (naturally - not in the form of an overseeing species that tends the life on a new world to remove heterotrophs). I'd also like to hear about any other potential obstacles that I should take into account if this autotroph world is to be believable.

Since "civilisation" is subjective, I'm looking for a world that has developed to the point of having at least one species using learned language to communicate and record history.

To clarify, I am looking for a natural evolution from scratch, not asking about machines. The introductory paragraph shows a simple example of a population ending up autotrophic, to contrast with my goal of a population that has always been autotrophic, right through its evolutionary history.

Also, the environment need not be Earth-like. I'm looking for environment/conditions under which this might be plausible. So if the limited amount of energy on Earth is a restricting factor, could it still be possible in a very different environment with much more available energy?

posted about 9 years ago

trichoplax‭

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