The World of Protists

What are Protists? Any organism that is NOT a plant, animal, fungus, or prokaryote (bacteria) All eukaryotes Most unicellular, some multicellular Range in size from a microscopic amoeba to giant seaweed

Where are Protists found? fresh water salt water inside organisms

Classified by the way they obtain nutrition. Animal-likeheterotrophs AKAprotozoans Plant-likeautotrophs Fungus-likeexternal digestion

1. Characteristics of Protozoans Heterotrophs Unicellular Classified by the way they move Ex: pseudopods, flagella, cilia, parasitic

Examples of Animal-like Protists that cause disease Entamoeba Trypanosome Giardia Plasmodium

Causes Amebic dysentery: parasitic disease of large intestine Protist: Entamoeba Causes Amebic dysentery: parasitic disease of large intestine Cause: contaminated food or water Symptoms: severe diarrhea, intestinal bleeding, sometimes death Found: Worldwide, higher incidences in developing countries

Causes African sleeping sickness: Protist: Trypanosome Causes African sleeping sickness: parasitic disease of the blood & spinal fluid Cause: infected tsetse fly Symptoms: uncontrollable sleepiness, high fever, & sometimes death Found: regions of Africa

Causes Giardiasis: Parasitic intestinal disease Protist: Giardia Causes Giardiasis: Parasitic intestinal disease Cause: contaminated food or water Symptoms: fatigue, diarrhea, and cramping Found: worldwide, in warm climates

Causes Malaria: parasitic disease in red blood cells Protist: Plasmodium Causes Malaria: parasitic disease in red blood cells Cause: infected female Anopheles mosquito Symptoms: flu-like chills & fever No vaccine exists, yet Found: Tropic zones worldwide

Ecological Role of Animal-like Protists Play essential roles in living world Live symbiotically w/other organisms ex. Trichonympha live inside termites help digest wood Recycle nutrients Food source for larger sea animals

2. Plant-like protists AKA algae or plankton Photoautotrophs Contain chlorophyll - but no roots, stems, or leaves Multi- or unicellular

Dinoflagellate Euglena Diatom Red algae Green algae

Ecological Role of Plant-like Protists Produce 70% of Earth’s oxygen 1st link in ocean’s food chain Algal Blooms – recycle sewage & other wastes Human uses of algae - sushi wraps, agar plates, ice cream, salad dressing, medicines, paints, polishes

3. Fungus-like Protists Heterotrophs Decompose dead organisms External digestion, then absorb nutrients Downy mildew on soybeans Slime mold

Ecological Role of Fungus-like Protists Recyclers of organic material Cause mildew and blight in grapes & tomatoes