Kingdom Protista: This system of classification is no longer used. It is now recognized that some protista are more closely related to _________________________________________________________ Protist – eukaryotes that are _____________________________________________________. Nutrition 1. 2. 3. Diverse habitats Plankton Phytoplankton – Zooplankton The _______________ and _______________ found in the protista are believed to have evolved through ____________________. LE 28-3 Plastid Dinoflagellates Secondary endosymbiosis Apicomplexans Red algae Cyanobacterium Primary endosymbiosis Stramenopiles Secondary endosymbiosis Heterotrophic eukaryote Plastid Euglenids Secondary endosymbiosis Green algae Chlorarachniophytes Euglenids – B. Euglenozoans 1. 2. Examples: Kinetoplastids – Trypanosoma – Ancestral eukaryote A. Diplomonads and Parabasalidsa 1. 2. 3. Examples: Giardia intestinalis and Trichomonas vaginalis Plants Charophyceans Chlorophytes Animalia Plantae Chlorophyta Rhodophyta (Opisthokonta) Red algae Metazoans Choanoflagellates Fungi Radiolaria Cercozoa Amoebozoa Fungi Cellular slime molds Plasmodial slime molds Entamoebas Gymnamoebas Radiolarians Foraminiferans Chlorarachniophytes Brown algae Golden algae Diatoms Ciliates Apicomplexans Stramenopila Oomycetes Euglenozoa Parabasala Alveolata Dinoflagellates Euglenids Kinetoplastids Parabasalids Diplomonads Diplomonadida A tentative phylogeny of eukaryotes divides eukaryotes into many clades LE 28-4 (Viridiplantae) LE 28-8 Long flagellum Eyespot Light detector Short flagellum Nucleus Euglena (LM) Contractile vacuole 5 µm Plasma membrane Chloroplast Pellicle Paramylon granule C. Alveolates – Examples: Dinoflagellates – LE 28-12 Apicomplexans - FEEDING, WASTE REMOVAL, AND WATER BALANCE Paramecium, like other freshwater protists, constantly takes in water by osmosis from the hypotonic environment. Bladderlike contractile vacuoles accumulate excess water from radial canals and periodically expel it through the plasma membrane. Ciliates – Contractile vacuole Paramecium feeds mainly on bacteria. Rows of cilia along a funnel-shaped oral groove move food into the cell mouth, where the food is engulfed into food vacuoles by phagocytosis. Oral groove Cell mouth Thousands of cilia cover the surface of Paramecium. Food vacuoles combine with lysosomes. As the food is digested, the vacuoles follow a looping path through the cell. 50 µm Micronucleus The undigested contents of food vacuoles are released when the vacuoles fuse with a specialized region of the plasma membrane that functions as an anal pore. Macronucleus CONJUGATION AND REPRODUCTION Meiosis of micronuclei produces four haploid micronuclei in each cell. Two cells of compatible mating strains align side by side and partially fuse. Compatible mates Three micronuclei in each cell disintegrate. The remaining micronucleus in each cell divides by mitosis. Macronucleus The cells swap one micronucleus. MEIOSIS FEEDING, WASTE REMOVAL, AND WATER BALANCE Paramecium, like other freshwater protists, constantly takes in water by osmosis from the hypotonic environment. Bladderlike contractile vacuoles accumulate excess water from radial canals and periodically expel it through the plasma membrane. Contractile vacuole Haploid micronucleus Diploid micronucleus Diploid micronucleus Paramecium feeds mainly on bacteria. Rows of cilia along a funnel-shaped oral groove move food into the cell mouth, where the food is engulfed into food vacuoles by phagocytosis. MICRONUCLEAR FUSION Oral groove Cell mouth Thousands of cilia cover the surface of Paramecium. The cells separate. Food vacuoles combine with lysosomes. As the food is digested, the vacuoles follow a looping path through the cell. 50 µm Micronucleus The undigested contents of food vacuoles are released when the vacuoles fuse with a specialized region of the plasma membrane that functions as an anal pore. Macronucleus CONJUGATION AND REPRODUCTION Meiosis of micronuclei Three micronuclei in each cell Two rounds of cytokinesis partition one maccronucleus and one macronucleus into each of four daughter cells. The original macronucleus disintegrates. Four micronuclei become macronuclei, while the other four remain micronuclei. Micronuclei Three rounds of mitosis without fuse, forming a diploid cytokinesis micronucleus. produce eight micronuclei. Key Conjugation Reproduction D. Stramenopiles 1. Examples: Oomycetes – LE 28-14_3 Oogonium Germ tube Egg nucleus (n) Cyst Antheridial hypha with sperm nuclei (n) MEIOSIS ASEXUAL REPRODUCTION Zoospore (2n) FERTILIZATION Zygote germination Zoosporangium (2n) Zygotes (2n) SEXUAL REPRODUCTION Key Haploid (n) Diploid (2n) Alternation of Generations – alternation of multicellular haploid and diploid stages Diatoms – Golden Algae – Brown Algae – E. Cercizoans and Radiolarians 1. Examples: Foraminiferans – Radiolarians – F. Amoebazoans 1. 2. Examples: Slime Molds – Plasmodial Slime Molds At one point in the life cycle, plasmodial slime molds form a mass called a plasmodium -- the plasmodium is undivided by membranes and contains many diploid nuclei -- it extends pseudopodia through decomposing material, engulfing food by phagocytosis LE 28-26 Feeding plasmodium Zygote (2n) Mature plasmodium (preparing to fruit) Young sporangium SYNGAMY 1 mm Amoeboid cells (n) Mature sporangium Key Flagellated cells (n) Cellular slime molds - G. Red Algae – H. Green Algae – Germinating spore Spores (n) MEIOSIS Haploid (n) Diploid (2n) Stalk
© Copyright 2024 Paperzz
