Kingdom Protista  Protists are so different from each other that you can think of this kingdom as the “junk drawer” kingdom.  However, protists do share some common characteristics:  They are all eukaryotes, or organisms that have cells with nuclei.  They all live in moist surroundings.

Types of Protists  One useful way to group protists is to divide them into three categories: Plant-like protists (algae) Animal-like protists (protozoans) Fungus-like protists (slime molds)

Plant-like Protists: Algae  All algae are autotrophs, which means that they make their own food.  Some algae live in the soil, other live on the barks of trees and still others live in fresh and salt water.  Algae exist in a wide variety of color because they contain different types of pigments  Algae can be green, yellow, red, brown, orange or even black.

Types of Algae  Green algae live mostly in fresh water but can be found on snow banks, damp soil, rocks and tree bark.  Diatoms, a type of golden algae, have a shell made of silica.  Euglenoids can move, unlike any other type of algae, to catch food when conditions for photosynthesis are not favorable.

Algae

Animal-like Protists: Protozoans  All protozoans are unicellular (made of only one cell).  Protozoans are all heterotrophs, which means that they cannot make their own food.  Most protozoans can move from place to place to obtain their food.  Scientists distinguish between four types of protozoans based on the way they move and live.

Types of Protozoans  Sarcodines: move by sending out a stream of cytoplasm called a pseudopod (false foot) and the rest of the cell follows.  The most common example is the amoeba.  Flagellates: move by the use of a whip like tail called a flagellum.  Ciliates: move by the use of short, hair like parts called cilia.  The best known ciliates are paramecium.  Sporozoans: these are non-moving. All are parasites that form spores during their life cycle.  The best known example is the one that causes malaria.

Protozoans

Fungus-like Protists: Slime Molds  All fungus-like protists are heterotrophs, have cell walls and use spores to reproduce.  They are able to move at some point in their lives.  They live in moist soil and on decaying plants and trees.  They move in an amoeba-like fashion, oozing along the surface.

Slime Molds