Protozoa (in Greek protohi = first an zoa = animals) are unicellular eukaryotes, (singular protozoan). While there is no exact definition of the term, most scientists use protozoan to refer to a unicellular heterotrophic protist. The name 'protozoa' is used for the more animal-like single celled organisms like amoebas and ciliates. The term 'algae' is used for the more plant-like micro organisms. However, the distinction between the two is often vague. Dinobryon (top image) has chloroplasts for photosynthesis but it can also feed on organic matter. It is even able to swim. Such an organism can neither be animal nor plant. Nowadays, all these unicellular organisms that are neither animals, plants, bacteria or fungi are called 'protists‘.