2.3 The Protists Learning Goals: Describe characteristics of eukaryotes Describe theories of the origin of eukaryotes (e.g., endosymbiosis) Describe the diversity of protists (in number of cells, types of metabolism, reproduction, etc.) Key features of the cilitates (e.g. Paramecium), euglenoids (e.g., Euglena), amoebas Reproduction of unicellular protists (binary fission, conjugation)

General Characteristics Eukaryotes Unicellular Mostly aerobic Lack specialized features No embryos or complex sex organs Some are motile Live in water or moist environements

General Characteristics Most diverse group of eukaryotes How is Kingdom Protista mainly classified in comparison to the other Kingdoms? Classified together because they do not fit into other kingdoms and not based on their similarities

One reason protists are important Surface waters of oceans and lakes have an abundance of protists called diatoms They are the leading primary producers in oceans and are the basis for marine and freshwater food chains.

Main Groupings

(1) Animal-like Protists Also called protozoans They are heterotrophs Some are parasites E.g. amoeba, ciliates, flagellates

(1) Animal-like Protists They are classified by the way they move: (i) CILIA Cilia are hair-like projections which beat together like oars to push the protist through its environment. National Human Genome Research Institute. Retrieved on July 30, 2010 from http://www.genome.gov/pressDisplay.cfm?photoID=85. Public Domain Access

(1) Animal-Like Protists (ii) FLAGELLA Flagella are tail like projections which rotate like a propeller

(1) Animal-like Protists (iii) PSEUDOPODS Temporary projections which push its body in a particular direction. The fluid within the cell is pushed against the cell wall which causes it to extend.

(2) Plant-like Protists E.g. euglenoids, diatoms, dinoflagellates They make their own food by photosynthesis.

(3) Fungus-like Protists E.g. slime molds and water molds They consume nutrients from living or dead organisms (decomposers) Some water molds are parasites

Homework Read pg. 60-64 and 66 Pg. 66 – Research This (omit 1) Kingdom Protista Worksheet (in pkg)