 Acritarchs may include the remains of a wide range of quite different kinds of organisms—ranging from the egg cases of small metazoans to resting cysts of many kinds of chlorophyta (green algae).It is likely that most acritarch species from the Paleozoic represent various stages of the life cycle of algae that were ancestral to the dinoflagellates.The nature of the organisms associated with older acritarchs is generally not well understood, though many are probably related to unicellular marine algae.