bio

Mutualism

A relationship between two species in which both benefit. The mycorrhizal symbiosis is the textbook case: the plant pays sugar (carbon) to the fungus, the fungus pays minerals and water to the plant, and neither thrives on land without the other. Crucially, mutualism requires no altruism — it is stable because each side gains for itself, and it frays the moment one party stops being fairly paid.