Protists Domain Eukarya Kingdom Protista Microscopic Critters Abound!
Characteristics of Kingdom Protista Heterogeneous assemblage of unicellular, colonial and multicellular Eukaryotes that do not have the distinctive characters of plants, animals or fungi Contains a number of organisms previously classified as plants, animals or fungi. Classification based on movement and pigment (our text) Cells typically 1 μm to 50 μm, up to 60 meters (seaweed)
Importance Important components of food chains. E.g. kelp beds are among the most productive ecosystems on earth Unicellular aquatic Protista (plankton) form an important component of the food chain. The photosynthetic ones are called phytoplankton and the heterotrophic ones are called zooplankton (which also includes many animal larvae or tiny crustaceans)
Motility Motility – the ability to move spontaneously and independently Some are motile, some are NOT motile Some move using: cilia flagella streaming (amoeba use “arms" called a pseudopod)
Domain Eucarya Kingdom Protista Phylum Sarcodina
Phylum Sarcodina • Unicellular • Move by pseudopodia • Some surrounded by a calcium "shell" • Amoeba has no definite shape • Shape is constantly changing • Food is surrounded by pseudopods and stored in a food vacuole Amoeba proteus
Sarcodina Reproduction • Asexual–only known method!
Move by cilia in a spiral path Phylum Ciliaphora • Unicellular • Nuclear dimorphism : two functionally distinct kinds of nucleii • Micronucleus is specialized for sexual exchange • Macronucleus is specialized for transcription
Paramecium Reproduction • Asexual – binary fission • Sexual - conjugation Under certain conditions, such as overcrowding or environmental stress, Paramecium turns from strictly asexual reproduction to sexual reproduction. Sexual reproduction involves the exchange of genetic material between two individuals of different 'mating strains'. Involves meiosis.
Reproductive Cycle And now for a pleasant review of mitosis and meiosis!
Phylum Zoomastigina The Flagellates • Move by flagellum or flagella • Other zooflagellates may live inside as parasites • Some diseases caused by flagellates are transmitted by insects • Can become infected by contaminated water • Some live in the digestive tracts of termites and assist in the digestion of cellulose.
Pathogenic examples of Zooflagellates • Giardia lamblia – “Hiker’s disease”
Trypanosomacruzi • Transmitted by insects-Reduviid insect • Causes Chagas’ disease Mainly in Latin America: 18 million are infected each year; 50,000 die yearly. Affects major organs: Heart Liver G.I. tract Brain http://www.cdc.gov/ncidod/dpd/parasites/chagasdisease/factsht_chagas_disease.htm
Vector - <L. vehere to carry • Metacyclic – infective stage • Trypomastigotesflagelatted form of parasite that lives in the blood. • Amastigotes or mastigotes - Unflagelatted form that lives in cells
Phylum Sporozoa Plasmodium • Unicellular • All Parasitic! • Responsible for malaria • Move by gliding motion in some stages
Domain Eucarya The Algae Kingdom Protista
Benefits of Algae • All algae provide food for microorganisms which larger animals and fish can eat • Surface and hair algae provide food for fish directly • All algae absorb excess pond nutrients like ammonia, nitrate, and phosphate • Suspended algae provides some shade to pond animals and plants in the spring • All algae provide oxygen during the day (but use it at night) • Hair algae provides a soft spawning site for fish.
Algae Classification Phylum Euglenaphyta • 800 to 1000 species • Photosynthetic when light available • Heterotrophic when light unavailable • Resemble protozoans due to flagella • Freshwater and brackish water inhabitants
Euglena Reproduction Binary Fission
Phylum Chlorophyta • 7,000 species • Most freshwater, but some terrestrial; a few marine • Contain chlorophylls a, b, and carotenoids • Unicellular, colonial, and multicellular
Spirogyra • Hair algae
Phylum Chrysophyta • 850 species • Store food as oils • Most unicellular, some colonial • Cell walls made of cellulose
Chrysophyta • Vaucheria
Phylum Bacillariophyta • 1150 species • Supply more oxygen than all other organisms • Store food as oil • Silica walls contain silica used for filters, insulate boilers, abrasive factor in toothpaste
Bacillariophyta • Diatoms
Phylum Phaeophyta • All multicellular • Almost all marine • Brown algae • Contain chlorophyll a, c, and fucozanthin • Provides algin – thickener in cheap ice cream • Stem-like structure has air bladders that allow it to float near surface of water
Phaeophyta • Fucus
Phylum Rhodophyta • Mostly marine • Multicellular • Color derived from phycobilins • Less than 30 cm long • Important in building reefs from calcium deposition • Products: agar, gelatin shells of drug capsules
Rhodophyta • Gelidium pulchrum
Phylum Dinoflagellata • Unicellular • Possess two flagella • Cell walls composed of cellulose • Mostly marine • Some bioluminescent • Responsible for red tides!
Dinoflagellates Ceratium sp. Protoperidinium sp.
Disadvantages of Algae • Suspended algae reduces clarity so that animals and plants cannot be seen in the pond • All algae reduce oxygen levels at night • All algae may cause pH fluctuations • All algae may cause the death of submerged plants, water lilies, etc. due to either reduced light levels or strangulation in the case of hair algae • Hair algae can clog filters, pumps, etc • Finally, many people find algae ugly
Eutrophication Can occur naturally or induced