Algae 2/3: 1. Unicelluar algae (various groups) 2. Green algae (Chlorophyta) Unicellular algae Euglena Figure 28.03x Euglena Diatom Dinoflagellate Golden Algae Unicellular algal groups • Cyanophyta (Blue-green Algae; prokaryotes) • Diatoms • Dinoflagellates • Chrysophyta • Chlorophyta (Green Algae) • Rhodophyta (Red Algae) Occurrence of Unicellulars • Phytoplankton (freshwater, marine) • Benthic microalgae • Epiphytic (on other algae) or on rocks, sediments, etc. • Terrestrial algae (walls, trees, etc) • Symbioses: in lichens, root nodules, marine sponges • Parasites (e.g. heterotropic dinoflagellates) • Hot springs • Ice algae (‘red snow’) How to distinguish between different unicellular algae? • Pigments? • Flagella: types of movement? • Type of reproduction (sexual, asexual)? • Life history? • Cell structure? • Formation of colonies or filaments? Cyanobacteria (Cyanophyta) • = ‘Blue-green Algae’ • Prokaryotic, no cell organelles • Pigments: chlorophyll a, phycoerythrin + phycocyanin • Only asexual reproduction • Some can fix atmospheric Nitrogen • Can form blooms • In extreme habitats (e.g. hot springs) • In lichens