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The Protists. Eukaryotes. Most unicellular. Most aerobic. Moist environments Can be photoheterotrophs, photoautotrophs, chemoheterotrophs or mixotrophs. Flagella or cilia. All protists can reproduce asexually, some sexually. Endosymbiosis. - PowerPoint PPT Presentation
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The Protists• Eukaryotes.• Most unicellular.• Most aerobic.• Moist environments• Can be photoheterotrophs, photoautotrophs,
chemoheterotrophs or mixotrophs.• Flagella or cilia.• All protists can reproduce asexually, some
sexually
Endosymbiosis• Eukaryotic cells evolved from symbiotic
combinations of prokaryotic cells.– Mitochondria aerobic heterotrophic
prokaryotic cells– Chloroplasts photosynthetic prokaryotes
Evidence for Endosymbiosis
Similarities between modern bacteria and the chloroplasts/mitochondria of eukaryotes:
*size*enzymes*circular DNA molecules*process of division*ribosomes similar
The Candidate Kingdoms• Archaezoa• Euglenozoa• Alveolata• Stramenopila• Rhodophyta• Green Algae
Candidate Kingdom Archaezoa
• Giardia • have two nuclei,
flagella, and no mitochondria (…parasites)
Candidate Kingdom EuglenozoaAutotrophic and/or
heterotrophic flagellates
• Euglena– 1 or 2 flagella
• Kinetoplastsparasitic, e.g. African Sleeping Sickness (bite of tsetse fly)
Trypanosoma
Candidate Kingdom Alveolata• Dinoflagellates, phytoplankton,
cause red tides, color from xanthophyll.
• Apicomplexans, plasmodium, causes malaria.
• Ciliates, paramecium
Next Group
Dinoflagellates
http://www.microscopy-uk.org.uk/mag/artsep01/dinof.html http://www.microscopy-uk.org.uk/mag/indexmag.html
Apicomplexans
Leishmania
Parasite infected erythrocyte
Life history of Plasmodium
Ciliates
Paramecium
Stentor
Vorticella
Pseudopod “Protists”
Taxonomic lineage unclear, so no clear kingdom found… i.e. “misfits”• Rhizopods, amoebas
• Actinopods, radiolarians and heliozoans (delicate silica shells).
• Foraminiferans, marine with porous calcium shells. Used as index fossils.
• Slime Molds, cytoplasmic streaming
Rhizopod
Amoeba
Actinopods
Radiolarians
Foraminiferans
Slime Molds• Plasmodial Slime Mold – Myxomycota. Heterotrophic,brightly colored,
multinucleated ameboid mass.
Candidate Kingdom Stramenopila• Diatoms (bacillariophyta)– unicellular
plankton with box-like silica walls. Diatomaceous earth.
• Golden Algae (chrysophyta) – yellow and brown carotene and xanthophyll pigments
• Brown Algae (phaeophyta)- largests and most complex. Seaweeds and kelps, may be as long as 60m.
• Water Molds (oomycota) – white rusts and downy mildews
Next Group
Diatoms
Golden Algae - Chrysophyta
Brown Algae - Phaeophyta
Kelp Harvesting
Kelp Structures• Analogous plant-like structures
– Body = thallus– Root-like structure – holdfast– Stem-like structure – stipe– Leaf-like structure - blades
Water molds, white rusts and downy mildews
White rust on spinachWater mold
Candidate Kingdom Rhodophyta
• Red color from pigment
• Marine • Multicellular• Carrageenan
thickener
Candidate Kingdom Green Algae
*Many scientists advocate inclusion of green algae into the plant kingdom.*More than 7000 species, mostly freshwater.
Ulva
*Unicellular – Chlamydomonas*Colonial – Volvox*Multicellular – Ulva
Green Algae - Chlorophyta
Chlamydomonas
Volvox
Spirogyra
Chlamydomonas Life Cycle
Ulva Life Cycle
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