Scientists have now begun to identify some of the early bacterial interaction which ultimately led to the development of plants and other multi-cellular organisms.
It's essentially bacterial mating of a sort.
I can see the conversation between the two bacteria:
"Hey baby, nice pseudopods."
"Thanks (blush). I've been going to the gym a lot. I love your Golgi Apparatus. It's soooo sexy."
"So wadda say we head over to the bright side of the pond and mingle in the ooze for a while."
"Oh, I'm sorry, I didn't tell you. I'm seeing someone else. His name is Frank, and he's got these massive mitochondria. They give him so much stamina and energy."
"Oh man, that sucks. Well, hit me up sometime if that you get tired of hangin' with the jocks."
And so it goes...