Get latest articles and stories on World at LatestLY. When plants first ventured onto the land, evolving from freshwater-dwelling algae, more than 500 million years ago, they transformed the planet. By drawing carbon dioxide from the air, they cooled Earth, and by eroding rock surfaces they helped build the soil that now covers so much land. World News | 480 Million-year-old Fossil Spores from Western Australia Record How Ancient Plants Spread to Land.