Then, a miracle occurred, perhaps the most dramatic natural event in our planet's history. This means that these sun-eating pioneers were able to absorb the sun's energy and use it to digest water and C02, releasing the precious atmospheric oxygen that later would allow the entire food chain to sprout and flourish in all its rich diversity. The miracle continues to this day. Even puddles of rain Algae flourish today in thousands of varieties. They may be found living on the ground or beneath the earth's surfaces, on the bark of trees, on rocks - and even within the bodies of higher plants and animals.
Some algae grow in colonies resembling plants.
Best known of these are the sea kelps, which can attain lengths of several hundred feet. However, algae such as these differ from true plants, in not having root, circulatory, and other complex transport systems. In all algae, whether macroalgae like the giant kelps or microalgae such as The Blue Green Algae, each cell is self-sufficient. If you break a piece of sea kelp off, it will retain its viability. All our modern green plants have since duplicated algae's historic feat of photosynthesis but algae still reign supreme among them.