I’ve thought about asking this several times, but hesitated because I’m not quiet sure how to articulate my thoughts. But, I’ll give it a try anyway.
What is the smallest creature/organism to have a brain? Of course, somebody’s going to ask, what do you mean by brain? OK, maybe brain isn’t the right term. I’ll try to explain what I mean by brain. I’m talking about a thinking process. At a bare minimum, something that allows an organism to react to it’s environment based on instinct.
For example, plant and animal cells react to their environment, but not based on any sort of thought, instinct, or emotion. They just, react. Whereas a microscopic flatworm has a basic nervous system, and brain, which allow it to do things, like search for food and use its ocelli to detect, and avoid light. So, even though it has no emotion or reasoning capabilities, I’m thinking there must be some active thinking process, however primitive, going on here, right?
Well, even if that wasn’t a very good example, I hope you get the gist of my question. Thank you.