Lecture_7._Protozoa_d2l.ppt

Announcements Exam Grades coming soon? New Lab Schedule Everything has been pushed back one week Feb 7th: Sponges Feb 14th: Lab Exam 1 Protozoa Chapter 5 Evolutionary Perspectives Ancient Group Endosymbiont Hypothesis Prokaryote eukaryote? Polyphyletic Heterotrophic Autotrophic General Characteristics Gr. proto, first + zoa, animal Eukaryotic Unicellular, some colonial Marine, freshwater, terrestrial and symbiotic species Protozoa Unicellular?but not simple! Locomotor Organelles Cilia or flagella, Pseudopodia Amoeboid Protozoans - Movement Types of pseudopodia Lobopodia http://www.youtube.com/watch?v=S9QGJ3JN8Kw&feature=related Amoeboid Protozoans - Movement Types of pseudopodia Filopodia Reticulopodia Axopodia Nutrition and Digestion Autotrophic Heterotrophic Phagotrophs Osmotrophs Endocytosis Phagocytosis Cytosome and cytopyge http://www.youtube.com/watch?v=W6rnhiMxtKU Nutrition and Digestion Excretion and Osmoregulation Gas exchange and excretion by diffusion Body size limitations What shape would you expect the largest protists to be? Osmoregulation Marine: isotonic Freshwater: hypotonic contractile vacuoles or water expulsion vacuoles Protists: Reproduction Asexual Binary fission Multiple fission Budding Sexual Alternate Encystment and Excystment Cysts Protozoan Phyla Focus on particular groups Only responsible for those that we talk about in lecture! Phylum Euglenozoa Freshwater 1 or 2 flagella Pellicule Mainly Phytoflagellates Some zooflagellates Orients to light source Phylum Euglenozoa: Class Trypanosomatidea Zooflagellates One or two flagella Parasitic Sleeping sickness and Trypanosoma brucei Phylum Ciliophora: Ciliates Marine and freshwater habitats Cilia Distinct cytostome (mouth) Phylum Ciliophora: Ciliates Cilia How do cilia differ from flagella? Locomotion Feeding http://www.youtube.com/watch?v=3ogFBAoZjo8&feature=related http://www.youtube.com/watch?v=Fc70Uk1fjTw&feature=related Figure 8.17 Didinium Paramecium tentacle Tokophyra Suctorian ciliate Ciliate Feeding Trichocysts Toxicysts Tentacle Phylum Ciliophora: Ciliates Two types of nuclei Macronucleus: controls general cell operations Micronucleus: reproductive function (synthesizes DNA) Asexual (binary fission) and sexual reproduction (conjugation) Conjugation What is Protozoa? Single cell Formally a single Phyla Now recognized as many Phyla Polyphyletic Unifying characteristic Phylum Dinozoa: Dinoflagellates Aquatic habitats Phytoflagellates Autotroph flagellated Two flagella: Equatorial Longitudinal Important Phylum Dinoflagellata: Zooxanthellae Mutualistic assocations Coral reefs Live and help coral reproduce Coral bleeching? zooxanthellae, coral loses color because protozoa are dying. Phylum Dinozoa: Red Tides Many produce toxic substances Accumulate in suspension feeders Example: Pfiesteria Phylum Apicomplexa Primarily marine All parasitic (endoparasitic) Apical complex No cilia or flagella Phylum Apicomplexa Malaria: vertebrate and mosquito hosts Plasmodium Coccidiosis: disease of poultry, sheep, cattle and rabbits Isopora and Eimeria Toxoplasmosis: disease of mammals, humans and birds Toxoplasma Figure 5_21 Amoebas Most free living in aquatic habitats However, some are pathogens of humans No flagellated life stage ?Naked? or Shelled Heterotrophic Pinocytosis and phagocytosis Amoeba: Pathogens Rhizopodans Entamoeba coli (= E. coli): can cause temporary mild gastrointestinal distress E. histolytica: causes amoebic dysentery