Algae
group of plant-like eukaryotic organisms which mostly grow in water and can photosynthesise / From Wikipedia, the free encyclopedia
Algae (singular: alga, plural: algae) are plant-like living things. They make food from sunlight by photosynthesis. The study of algae is called phycology or algology.
The term covers different groups, and they are not all closely related. They are a polyphyletic group. The term lumps together different kinds of organisms. They are very ancient, and existed long before other types of plants. They date back to the Mesoproterozoic, over a thousand million years ago.[1] They are not quite the first type of life, because they all seem to use plastids which originate in cyanobacteria.[2]
They have in common that they are autotrophic: they use natural sources of energy and simple inorganic materials. As non-vascular plants they do not have the structure of land plants. The name "algae" is convenient but a loose term. Recently, it has become clear how different the types of algae are.[3][4]