Rhizaria Rhizaria Rhizaria Rhizaria Archaeaplastida
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3/7/2011 Rhizaria Rhizaria • DNA unites • Chlorarachniophytes • Diverse morphologies – Secondary endosymbiosis • Many amoebas • Green Alga – – Convergence in forming Many mixotrophic pseudopodia – Tropical oceans • Rhizarian amoebas have thread‐like pseudopodia – Nets w/ pseudopodia Chlorarachniophytes Foraminiferans Radiolarians Rhizaria Rhizaria • Foraminiferans • Radiolarians – Often called “forams” – Delicate, symmetrical – Porous shells (tests) silica skeletons hardened with CaCO3 – Pseudopodia reinforced – Symbiotic photosynthetic algae by microtubules – Single‐celled • Thin layer of cytoplasm • Some grow to several cm – Marine – Well‐represented as fossils • Useful in aging sediment Archaeaplastida Archaeaplastida • Red and Green Algae • Red Algae • Closest relatives of land plants – Also known as rhodophytes • Chloroplast derived from • Phycoerythrin • Less red in shallow water cyanobtibacterium – Some parasitic (no pigments) – Absorb penetrating blue and green light • 260 m depth – Sushi wraps 1 3/7/2011 Archaeaplastida Archaeaplastida • Green Algae • Green Algae – Chloroplast structure similar Chlorophytes to land plants – Most freshwater, some marine, some terrestrial – Should possibly be in plant kingdom – Some symbionts – Two Groups: – Even snow‐living Chlorophytes – Unicellular, colonial, Charophyceans multicellular – Biflagellate gametes Archaeaplastida Archaeaplastida • Green Algae • Green Algae Chlorophytes Chlorophytes Chlamydomonas Colonial: Volvox Archaeaplastida Archaeaplastida • Green Algae • Green Algae Chlorophytes Chlorophytes Multicellular: Ulva Multinucleate: Caulerpa 2 3/7/2011 Unikonts Unikonts • Controversial • Amoebozoans – Myosin proteins, some genetic studies – Lobe or tube‐shaped pseudopodia – Slime Molds • Two main groups strongly supported • Fruiting bodies – Amoebozoans – Opisthokonts – Gymnamoebas • Will be discussed later • Unicellular heterotrophs – Entamoebas • Parasites (amebic dysentery) Unikonts Unikonts • Amoebozoans • Amoebozoans – Slime Molds – Slime Molds Plasmodial Slime Mold Cellular Slime Mold Ecology of Protists • Found almost anywhere with water – Oceans, ponds, streams, moist soil • Symbiosis – Photosynthetic dinoflagellates in corals (90% energy) – Termites (containing protists containing prokaryotes) – Sudden Oak Death • Photosynthesis – 25% by protists 3 3/8/2011 Land Plants Land Plants came from Green Algae • 500 mya eukaryotes came ashore • Charophytes • 370 mya tall plants • Synapomorphies: • ~290,000 species – Rosette cellulose‐synthesizi – Most flowering plants – PiPeroxisome enzymes • Anti‐photorespiration • Occur almost everywhere on land – Flagellated sperm structure – Except too cold or too dry – Phragmoplast • HUGE effects on habitat • Microtubules before cell plate Land Plants came from Green Algae Moving to Land • Charophytes • Benefits Chara – Unfiltered sunlight – Plentiful CO Coleochaete 2 – Mineral‐rich soil – Initial lack of herbivores • Problems – Desiccation and Structural Support Moving to Land What is a “True Plant”? • Charophytes have sporopollenin • Embryophytes – Plants do too – Plants w/ embryos • Plants adapted to increase • Possible addition structural support and of green algae gain the ability to retain water 1.