Kingdom Protista

What is a Protist? A Protist is any organism that is not a plant, animal, fungus, or prokaryote. Very diverse kingdom Single celled  Multicellular Range in size from μm to 50m+ Plant like, animal like and fungus like!

Evolution of Protists Protista comes from Greek words meaning “the very first” First eukaryotes (1.5 billion years ago) May have evolved through the endosymbiosis of prokaryotic cells

Classification of Protists Grouped according to how they obtain nutrition. 3 main groups: animal like plant like fungus like

Animal-like Protists Once called protozoa (first animals) Heterotrophs unicellular Grouped according to their method of movement. 4 Groups: Zooflagellates Sarcodines Ciliates Sporozoans

Zooflagellates Belong to phylum Zoomastigina Swim using flagella Feed by absorbing Live in lakes, streams, and bodies of other organisms Examples: Trichonympha & Trypanosoma

Sarcodines Belong to phylum Sarcodina Live in water Use pseudopods for movement and feeding Example: Amoeba move by streaming cytoplasm into pseudopods (amoeboid movement) http://www.youtube.com/watch?v=7pR7TNzJ_pA

Other sarcodines: Foraminiferans have shells made of CaCO3 Heliozoans (radiolarians) have shells made of SiO2

Ciliates Belong to phylum Ciliophora Use cilia for movement and feeding Most complex unicellular protists Example : Paramecium http://www.youtube.com/watch?v=fmwN_mD7TvY

Special features of ciliates: Trichocysts for defense Macronucleus – working nucleus Micronucleus – “back up copy” of genes Become genetically different by conjugation

Sporozoans Belong to phylum Sporozoa No means of movement All parasitic with complex life cycles involving more than one host Example: Plasmodium (causes malaria)

Diseases caused by Animal-like Protists African sleeping sickness Dysentary Malaria

Ecology of Animal-like Protists Some live symbiotically within other organisms Parasites Decomposers Part of food chain