* organisms that cannot be classified into any other group (plant, animal, fungus, bacteria) * organisms that are typically made up of just one cell * organisms that can be made up of many cells

* Scientists struggle to group them * They are currently grouped based on how the obtain nutrition (food) * 3 ways to obtain food = 3 groups of protists * Digest food internally (consume food) = Protazoan * Capable of producing their own food = Algae * Obtain food externally (break down decaying material) = Slime Molds

* Grouped based on how they move: * Sarcodinians – move with lobes of cytoplasm (pseudopodia) that extend outward * Zooflagellates – move by flagellum * Ciliates – move by cillia * Sporozoans – require presence of a host to move

* Grouped as unicellular or multicellular: * Unicellular: * Multicellular: * Algae provide environment with oxygen * Algae serve as a major food source

* With your partner, explain how protozoans are different from algae. * Some key differences include: protozoans consume food while algae make their own food, protozoans are grouped based on movement while algae are grouped based on number of cells, algae are mainly found in aquatic systems while protozoans can be found in a variety of locations, algae appear to be very beneficial and some protozoans are harmful.

* 3 types: * Acellular slime molds * Cellular slime molds * Water molds * Saprophytic – grows on and takes nourishment from dead or decaying matter