Kingdom Protista

Some basic facts Protists appeared in the fossil records about 1.5 billion years ago – that makes them more recent than bacteria. They are eukaryotes (have membrane- bound organelles and nucleus). Most of them are microscopic, and unicellular (except for red and brown algae)

Categories Protists can fall into one of 3 categories: 1. Animal-like Protists 2. Plant-like Protists 3. Fungi-like Protists Amoeba Euglena Slime Mould

Animal-like Protists Examples include: Amoebas, Paramecium, Giardia, and Plasmodium These are all heterotrophic (derive nutrition from consuming other organisms). Like animals, these protists can move in order to find food. Unlike animals, these are all unicellular.

Movement Animal-like protists move by using one of the following: –Pseudopods: finger-like projections that drag protist forward and can also trap food –Cilia: tiny hairs that beat in water, and can also move food towards oral opening –Flagella: whip-like tail that propels protist through water

Pseudopods

Cilia

Flagella

Plant-like Protists Examples: Euglena, Dinoflagellates, Diatoms, and Algaes These are autotrophic (must produce their own food) Can be found in water, soil and tree barks Form the basis of aquatic food chains Important producers of oxygen

Euglena Are autotrophs in light, and heterotrophs when dark Are unicelluar Some have flagella

Dinoflagellates Unicellular Have two flagella Covered by stiff plates Found in the ocean

Diatoms Unicellular Have glass-like cell walls

Algaes Green algaes – unicellular; may form colonies; live in fresh and salt water Red algaes – multicellular; often called seaweed; live in salt water Brown algaes – multicellular; seaweeds; in salt water

Green algaeRed algae Brown algae

Fungi-like Protists These are multi-cellular, heterotrophic and are able to move at some point in their lives Water moulds – live in water or moist environment Slime moulds- lives on moist soil and decaying plants

Water mould Slime mould