Educational content: Ecology
The game teaches ecology, the relationships between lifeforms.
The first video game about Educational content: Ecology was released in 1980.
Note the game must actually teach aspects of the science of ecology, not just the idea environmentalism. Things like recycling, large packaging, conservation, oil spill clean up, cuddly cute baby carnivores, can be utilized but do not inherently teach ecology by their mere presence in a game.