Transcript unikont
Fig. 28-03a Parabasalids Dinoflagellates Apicomplexan s Ciliates Diatoms Stramenopiles Golden algae Chromalveolata Alveolate s the 5 supergroups Euglenozoans Excavata Diplomonads Brown algae Oomycetes Forams Radiolarians Chlorophytes Charophyceans Land plants Archaeplastida Red algae Rhizaria Chlorarachniophytes Slime molds Gymnamoebas Nucleariids Fungi Choanoflagellates Animals Unikonta Entamoebas (Plantae) Concept 28.6: Unikonts include protists that are closely related to fungi and animals • The supergroup Unikonta includes animals, fungi, and some protists • This group includes two clades: the amoebozoans and the opisthokonts (animals, fungi, and related protists) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 28-UN5 Excavata Chromalveolata Rhizaria Archaeplastida Amoebozoans Fungi Choanoflagellates Animals Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Unikonta Nucleariids Fig. 28-23 RESULTS Choanoflagellates Animals Unikonta Fungi Common ancestor of all eukaryotes Amoebozoans Diplomonads Excavata Euglenozoans Alveolates Chromalveolata Stramenopiles DHFR-TS gene fusion Rhizarians Red algae Green algae Stechman and Smith, 2002 Rhizaria Plants Archaeplastida Amoebozoans • Amoebozoans are amoeba that have lobe- or tube-shaped, rather than threadlike, pseudopodia • They include gymnamoebas, entamoebas, and slime molds Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Slime Molds • Slime molds, or mycetozoans, were once thought to be fungi • Molecular systematics places slime molds in the clade Amoebozoa Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Plasmodial Slime Molds • Many species of plasmodial slime molds are brightly pigmented, usually yellow or orange Video: Plasmodial Slime Mold Video: Plasmodial Slime Mold Streaming Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Plasmodial “sporangia” • At one point in the life cycle, plasmodial slime molds form a mass called a plasmodium (not to be confused with malarial Plasmodium) • The plasmodium is undivided by membranes and contains many diploid nuclei • It extends pseudopodia through decomposing material, engulfing food by phagocytosis Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Cellular Slime Molds • Cellular slime molds form multicellular aggregates in which cells are separated by their membranes • Cells feed individually, but can aggregate to form a fruiting body! • Dictyostelium discoideum is an experimental model for studying the evolution of multicellularity Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 28-25-1 Spores (n) Emerging amoeba (n) Solitary amoebas (feeding stage) (n) 600 µm Fruiting bodies (n) ASEXUAL REPRODUCTION Aggregated amoebas Migrating aggregate Key 200 µm Haploid (n) Diploid (2n) Fig. 28-25-2 Spores (n) FERTILIZATION Emerging amoeba (n) Zygote (2n) SEXUAL REPRODUCTION Solitary amoebas (feeding stage) (n) 600 µm Fruiting bodies (n) MEIOSIS ASEXUAL REPRODUCTION Amoebas (n) Aggregated amoebas Migrating aggregate Key 200 µm Haploid (n) Diploid (2n) Gymnamoebas • Gymnamoebas are common unicellular amoebozoans in soil as well as freshwater and marine environments • Most gymnamoebas are heterotrophic and actively seek and consume bacteria and other protists Video: Amoeba Video: Amoeba Pseudopodia Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Problem Amoebas • Entamoebas are parasites of vertebrates and some invertebrates • Entamoeba histolytica causes amebic dysentery in humans • Acanthamoeba Water born eye pathogen contact wearers beware! (spiny) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Opisthokonts • Opisthokonts include animals, fungi, and several groups of protists Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Gymnamoebas Entamoebas Opisthokonts Nucleariids Fungi Choanoflagellates Animals Unikonta Amoebozoans Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Slime molds