How plants came to be

Modern day plants come from many lineages which trace back to a very important event: endosymbiosis. Endosymbiosis is the engulfing of an organism by something else and thus lives inside the other. In modern day plants, this began with cyanobacteria. Cyanobacteria is a blue-green algae that is photosynthetic. In the earliest forms of cyanobacteria, they did not release O2 into the atmosphere. But later down the line they began oxidizing. For plants to evolve, the primary event of endosymbiosis occurred. A eukaryotic cell engulfed the cyanobacteria and degenerated into a chloroplast. After this event, a second endosymbiosis event occurred that diverged into red and green algae and thus their divergents. Without these events of endosymbiosis, the ancestors of plants wouldn’t have been able to evolve into what they are today.