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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.
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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
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)
Fig. 28-UN5 Excavata Chromalveolata Rhizaria Archaeplastida Amoebozoans Nucleariids Fungi Unikonta Choanoflagellates Animals
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
Amoebozoans • Amoebozoans are amoeba that have lobe- or tube-shaped, rather than threadlike, pseudopodia • They include gymnamoebas, entamoebas, and slime molds
Slime Molds • Slime molds, or mycetozoans, were once thought to be fungi • Molecular systematics places slime molds in the clade Amoebozoa
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
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
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
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
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
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
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)
Opisthokonts • Opisthokonts include animals, fungi, and several groups of protists
Slime molds Amoebozoans Gymnamoebas Entamoebas Nucleariids Unikonta Fungi Opisthokonts Choanoflagellates Animals