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A Walk Through Time A Walk Through Time AssignmentsAssignments
Check 102 Web Site
““Protista”Protista”• One-celled to simple colonies to plant-like (but
these related to simple forms)• Cells eukaryotic• Photosynthetic and heterotrophic metabolisms• Now usually split into several kingdoms• Not plants, fungi, nor animals
Spirogyra
Amoeba
Ecology of the ProtistsEcology of the Protists
• Though small, play major roles* 65 % of earth’s net primary production
(phytoplankton)* Microfeeders of bacteria, other protists* Food for larger plankton & animals* Habitats for other organisms* Decomposers* Parasites of plants and animals
The Eukaryotic cellThe Eukaryotic cell
Paramecium, a ciliated protozoan
This view is under Nomarski phase contrast
Eukaryotic vs. prokaryotic cellsEukaryotic vs. prokaryotic cells
• Size* Prokaryotes ≤ 10 µm* Eukaryotes ≥ 10 µm
• Complexity* Prokaryotes – simple* Eukaryotes – complex
• Location of chromosomes* Prokaryotes – free in cytosol* Eukaryotes – within a nucleus
• Flagellar mechanisms differ
Bacteria & Archea
protists, Fungi, Plants, Animals
Bacterium (prokaryote)
Animal (eukaryote)
Plant (eukaryote)
Figures 7.4, 7.7, 7.8
(Actual size relative to eukaryotes below)
Protista as a single “kingdom”Protista as a single “kingdom”Functional gFunctional groupsroups
• Algae – photosynthetic• Protozoa – non photosynthetic, consumers• Fungus-like Protists – nonphotosynthetic,
hyphal
• Each group is polyphyletic
““Protozoa”Protozoa”
• Protista that are heterotrophic by injestion
• Motile* pseudopodia – amoebas* flagella – flagellates* cilia – ciliates
• Ancent and advanced groups
• Polyphyletic (i.e. phyla not closely related)
PseudopodiaPseudopodia
Movie of Pseudopodial movement in Amoeba
PseudopodiaPseudopodia
Actinophrys
FlagellaFlagella
Paranema
FlagellaFlagella
Giardia
CiliaCilia
Paramecium
Macronucleusw/ micronuclei
behind
Oral groove on surface
Site of cell “anus”
Food vacuoles
Cilia
Undulating membrane in groove (ciliary)
Contractile vacuoles
Paramecium, a ciliated protozoan
CiliaCilia
Euplotes