‘Algae’ is an artificial concept for a diverse assemblage that spans four of the five supergroups of eukaryotes and one group of prokaryotes in the tree of life.
Although the precise evolutionary relationships of these groups are still open to debate, the name 'algae' is still used as a term of convenience.
Algae range from single cells through to complex multicellular forms several metres in length.
Learn more about these unicellular photosynthetic organisms and their unique silica cell wall.
Cyanobacteria are prokaryotes more closely related to bacteria than other algae.
Mostly marine-based, brown algae range from unicellular organisms to seaweeds over 50 metres long.
These photosynthetic organisms live mostly in freshwater environments.
Red algae are an ancient species-rich group of organisms with diverse morphology and anatomy.
Although green algae are mostly aquatic, certain groups grow on soil, trees or rocks.
Unicellular euglenoids often move with a characteristic squirming motion.
Accessory pigments give golden-brown algae their characteristic colour.