Table 1.

Classification of microbial exchange between two organisms involving two goods

	Mutualism		Exploitation		Self-sufficiency
	Organism 1	Organism 2	Organism 1	Organism 2	Organism 1	Organism 2
Good 1	p	c	p,c	c	p,c	p,c
Good 2	c	p	—	p,c	p,c	p,c

A p indicates that a good is produced and a c indicates that it is consumed. We assume that if an organism consumes a good, it benefits in some way