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Fig. 28-03a PowerPoint Presentation
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Fig. 28-03a

Fig. 28-03a

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Fig. 28-03a

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  1. Fig. 28-03a Diplomonads Excavata Parabasalids the 5 supergroups Euglenozoans Dinoflagellates Apicomplexans Alveolates Ciliates Chromalveolata Diatoms Golden algae Brown algae Stramenopiles Oomycetes Chlorarachniophytes Rhizaria Forams Radiolarians Red algae (Plantae) Chlorophytes Archaeplastida Green algae Charophyceans Land plants Slime molds Gymnamoebas Amoebozoans Entamoebas Nucleariids Unikonta Fungi Opisthokonts Choanoflagellates Animals

  2. 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)

  3. Fig. 28-UN5 Excavata Chromalveolata Rhizaria Archaeplastida Amoebozoans Nucleariids Fungi Unikonta Choanoflagellates Animals

  4. Fig. 28-23 RESULTS Choanoflagellates Animals Unikonta Fungi Common ancestor of all eukaryotes Amoebozoans Diplomonads Excavata Euglenozoans Alveolates Chromalveolata Stramenopiles DHFR-TS gene fusion Rhizaria Rhizarians Red algae Green algae Archaeplastida Stechman and Smith, 2002 Plants

  5. Amoebozoans • Amoebozoans are amoeba that have lobe- or tube-shaped, rather than threadlike, pseudopodia • They include gymnamoebas, entamoebas, and slime molds

  6. Slime Molds • Slime molds, or mycetozoans, were once thought to be fungi • Molecular systematics places slime molds in the clade Amoebozoa

  7. 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

  8. Plasmodial “sporangia”

  9. 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

  10. 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

  11. 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 Haploid (n) Diploid (2n) 200 µm

  12. Fig. 28-25-2 Spores (n) FERTILIZATION Emerging amoeba (n) Zygote (2n) SEXUAL REPRODUCTION Solitary amoebas (feeding stage) (n) 600 µm MEIOSIS Fruiting bodies (n) ASEXUAL REPRODUCTION Amoebas (n) Aggregated amoebas Migrating aggregate Key Haploid (n) Diploid (2n) 200 µm

  13. 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

  14. 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)

  15. Opisthokonts • Opisthokonts include animals, fungi, and several groups of protists

  16. Slime molds Amoebozoans Gymnamoebas Entamoebas Nucleariids Unikonta Fungi Opisthokonts Choanoflagellates Animals