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Kingdom Protista The most diverse group of organisms Discovery of Protists • Anton van Leeuwenhoek – Lived around 300 years ago – First to use a microscope to see cells – “No more pleasant sight has met my eye than this of so many thousands of living creatures in one small drop of water.” What can you find in a single drop of water?? Evolution of Protists • Evolved from prokaryotes 1.5 billion years ago • Protists are the first known eukaryotic organisms • They would lead to the evolution of fungi, plants and animals • A eukaryote that cannot be classified as fungi, plant or animal • An organism that has very diverse characteristics • A microscopic organism that lives in water • Can be grouped into two general categories: – Protozoa – Algae What is a protist? How many cells?? (It depends!) • Most protists are unicellular, but some are multicellular • Some are colonial – each individual has a specific number of cells – all individuals together make up the colony – the colony acts like a multi-celled organism Volvox Colonies • http://video.google.com/videoplay?docid=3471807967695834419 What is their function? (It depends!) Some are… • Producers – many protists are photosynthetic and are major contributors to the Earth’s oxygen atmosphere • Consumers – some protists eat other organisms for energy • Decomposers – some breakdown dead organisms to return nutrients to the soil The Protozoa Blues • http://video.google.com/videoplay?docid=35 78205676570425677&q=protozoa+site%3Avid eo.google.com&total=13&start=0&num=10&s o=0&type=search&plindex=2 Protists: The 411 1. 2. 3. 4. All are Eukaryotes All are aerobic (require oxygen) All have mitochondria All live in water-based environments (fresh water, oceans and seas, damp soil, snow) 5. Some have chloroplasts 6. Some reproduce asexually, some sexually 3 Main Types • Plant-like protists • Animal-like protists • Fungus-like protists Plant-like Protists (AKA algae) • Algae are protists that are strictly photosynthetic • Algae are distinguished by the type of photosynthetic pigment they contain • Algae are also classified based on their cell or body shape • Most are found in freshwater • Major part of plankton (small organisms found on the surface of a body of water) • Contain chloroplasts and undergo photosynthesis Green Algae – Phylum Chlorophyta Biscayne Bay – Miami, FL Brown Algae – Phylum Phaeophyta • Multicellular • Found in marine and coastal regions • Examples: kelp, seaweed • Can be up to 30 m long • Provide protection and shelter for many coastal fish Red Algae – Phylum Rhodophyta • Multicellular • Found in tropical zones and deep ocean regions • Able to absorb light that penetrates deep waters Caloosahatchee River, SE Florida (Gulf of Mexico side of Florida) Diatoms – • Unicellular Phylum • Cell wall contains silica Bacillariophyta (mineral found in glass) • Double shell (fits together like the bottom and top of a shoe box) • Their shells are used to make reflective paints Dinoflagellates – Phylum Dinoflagellata • Have 2 flagella • Huge increases in population cause red tides = fish are killed due to less oxygen in the water, water looks red due to overpopulation • Most are found in saltwater Euglenoids – Phylum Euglenophyta • One flagella • Eyespot – light sensitive organ that tells the organism to move toward light • Found mostly in freshwater Animal-like Protists (AKA protozoa) • Classified based on their type of nutrition • Ingest their food by endocytosis (engulfing food into the cytoplasm) Paramecium – Phylum Ciliophora • Move by beating tiny hair-like structures called cilia • The cilia act in unison like oars on a boat • Have one large contractile vacuole for water and waste storage Amoebas – Phylum Rhizopoda • Move by pseudopodia (false feet) • Amoebas can live in water, soil or living organisms Sporozoans – Phylum Apicomplexa • All parasites • Transmitted through bloodeating insects or feces Malaria • One of the most deadly diseases in humans • Caused by a protist called plasmodium • A mosquito bites an individual and the protist is injected into the blood stream • Over 100 million people have malaria • Up to 3 million people, mostly children, die from it every year • Symptoms include severe chills, fever, sweating, and confusion • Victims typically die of other related complications including anemia, kidney failure or brain damage • Malaria and fake drugs: http://video.google.com/videoplay?docid=89 97083794746163547&q=malaria&total=1547 &start=0&num=10&so=0&type=search&plind ex=3 (first 10 minutes) Fungus-like Protists (AKA molds) • Two groups – Plasmodial slime molds • Phylum Myxomycota • Look like oozing slime • Absorb bacteria and nutrients as they slowly move – Water molds • Phylum Oomycota • Usually feed on dead material • Responsible for the potato famine in Ireland (18451850) that killed almost 1 million people