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Fossils of Eukarya? Cell walls contain resistant biopolymers e.g. algeanans Preservation superior to prokaryotes Record of acritarchs since 1.8 Ga ARCHAEA.

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Presentation on theme: "Fossils of Eukarya? Cell walls contain resistant biopolymers e.g. algeanans Preservation superior to prokaryotes Record of acritarchs since 1.8 Ga ARCHAEA."— Presentation transcript:

1 Fossils of Eukarya? Cell walls contain resistant biopolymers e.g. algeanans Preservation superior to prokaryotes Record of acritarchs since 1.8 Ga ARCHAEA BACTERIA EUCARYA

2 Zones Range-chart plots show four acanthomorph zones new genus Tanarium irregulare Tanarium conoideum Appendisphaera

3 Fig.3. Divergence time estimates for major groups of fungi, plants, and animals (Table 1). Thick horizontal bars at branch points are 1 SE; narrow bars delimit 95% confidence intervals; thick bars on branches denote fossil record of fungi; solid circles are calibration points; open circle is internal (fungal) fossil constraint, H, Hemiascomy cetes, The branching order of three groups (Ascomycota, Basidiomycota, Mucorales/Blastocladiales) is shown as unresolved for topological consistency. On the basis of branching order from other data (11, 12), glomalean fungi diverged after chytrids and before the basidiomycotan/ascomycotan divergence, ~1400 to 1200 Ma.

4 Fossil Lipids lipids from livinghydrocarbon fossils prokaryotes preservation of skeleton & 13 C content bio geo

5 EUCARYA BACTERIA >2.7 Ga green sulfur bacteria Des ulfurococcus Sulfolobus gram pos itives Thermofilum Thermoproteus protcobacteria Thermotoga Pyrodictium Methano- thermus Methanopyrus R cyanobacteria avobacteria Pyrococcus Pyro ba culum Methanobacterium Archaeoglobus Halococcus Halobacterium Methanoplanus Methanospirillum Methanos arcina Methanococcus 1 jannaschii 2 igneus 3 thermolithotrophicus 4 vanniellii man animals micros poridia fungi flagellates diplomonads plants ciliates slime molds

6 Complexity of Extant Life Species Type Approx. Gene Number Prokaryotes Eschericia coli typical bacterium 4,000 Protists O. Similis S. Cerevisiae Distyostelium discoideum protozoan yeast slime mould 12,000-15,000 7,000 12,500 Metazoan C. elegans Nematode 17,800 D. melanogaster Insect 12,000-16,000 S. purpuratas Echinoderm <25,000 Fugu rubripes Fish 50,000-10,0000 Mus musculus Mammal 80,000 Homo sapiens mammal 60,000-80,000 After Maynard-Smith and Szathmary, 1999

7 independent replicators chromosomes RNA as a gene and enzyme DNA genes, protein enzymes Prokaryotic cells Cells with nuclei & organelles ie eukaryotes asexual clones sexual populations single bodied organisms fungi, metazoans and metaphytes solitary individuals colonies with non-reproductive castes primate societies human societies with language After Maynard-Smith and Szathmary, 1999 Major Transitions in Origin/Evolution of Life replicating molecules populations of molecules in protocells

8 Model for Evolution of Atm-Ocean Redox 1. Chlorphytes 2. Ciliates 3. Dinoflagellates 4. Rhodophytes 5.acritarchs 6. Stramenopiles 7. Testate amoebe Fig. 1. Biological and geochemical changes during the Proterozoic Eon. Color gradations denote postulated changes in deep sea redox. (A) Periods of deposition of banded iron formations. (B) Range of values of A 34 S, the difference in δ 34 S between coeval marine sulfides and sulfates. Dashed line: 34 S= 20%, the maximum Archean valune. Dotted line: 34 S= 45%, the maximum fractionation associated with single-step BSR, Asterisk: 34 S determined from a single sample, and thus not well constrained. (C) Range of values of Δ34c carb (after a compilation by A. J. Kaufman). The frequency and magnitude of variations in the Paleoprot- erozoic are somewhat uncertain. (D) Eukaryoyic evolution, as indicated by the first appearances of bidy fossils (solid lins) and molecular biomarkers (dotted lines), including chlorophytes (1), ciliates (2), possibly stemgroups (5), stramenopiles (6), and testate amoebae (7). See text for geochemical references, Fossil distributions from (147). Time before present (Ma) Archean Eon Proterozoic Eon Paleo- Meso-Neo-

9 Fig. 2. Schematic depiction of ettects of changing ocean redox conditions on the depth distributions of Mo (dashed lines) and Fe (solid lines). Influences of nutrient-type depletion and aeolian inputs on surface seawater concentrations are omitted for simplicity. Color gradations are tha same as Fig. 1. During the Archean, oceans are anoxic but not sulfidic. Significant O 2 is only associated with cyanobacterial blooms. Mo is scare because it is not readily mobilized from crustal rocks during weathering under low PO 2. Fe is abundant in the absence of O2 and H 2 S. From 1850 to 1250 Ma, moderate PO 2 oxygenates surface waters but sulfidic deep waters develop. Mo is scarce because of rapid removal in sulfidic waters. Mo is somewhat elevated at the surface because of upper ocean oxygenates and enhanced oxidative weathering. Fe, as in the modern Black Sea, is depleted in sulfidic deep waters, severely depleted in oxic surface waters, and enriched near the redoxcline where both O 2 and H 2 S are scarce. During the Phanerozoic, O 2 penetrates to the sediment-water interface. Mo and Fe distributions are similar to todays. See text for details and references. Archean MaPhanerozoic Upper ocean Deep ocean Ocean sediments Transition period


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