During the Ordovician period, life was diversifying rapidly in the oceans — but a quiet revolution was beginning on land. Descended from green algae, the first land plants emerged along damp shorelines and floodplains. These early plants were small, simple, and likely moss-like. They reproduced with spores and lacked deep roots or wood, but they evolved critical adaptations for terrestrial survival: a protective waxy cuticle to reduce water loss, structural tissues to stand upright, and spores capable of dispersal without open water.

Their arrival transformed Earth’s surface. Even modest plant cover began stabilizing soils, altering atmospheric chemistry, and reshaping weathering cycles. The greening of the continents was gradual — but it changed the planet permanently.