Flexi Says: Types of algae include red and green algae, and euglenids, and dinoflagellates. Scientists think that red and green algae evolved from endosymbiotic relationships with cyanobacteria. Their chloroplasts have two membranes because the cell membranes of the cyanobacteria became additional plasma membranes of the chloroplasts. Scientists think that euglenids and dinoflagellates evolved later, from endosymbiotic relationships with green and red algae. This is why their chloroplasts have three membranes.
