A Walk Through Time Assignments Check 102 Web Site

“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 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 cell Paramecium, a ciliated protozoan This view is under Nomarski phase contrast

Eukaryotic 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” Functional groups Algae – photosynthetic Protozoa – non photosynthetic, consumers Fungus-like Protists – nonphotosynthetic, hyphal Each group is polyphyletic

“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)

Pseudopodia Movie of Pseudopodial movement in Amoeba

Pseudopodia Actinophrys

Flagella Paranema

Flagella Giardia

Cilia Paramecium

Macronucleus w/ micronuclei behind Oral groove on surface Site of cell “anus” Food vacuoles Cilia Undulating membrane in groove (ciliary) Contractile vacuoles Paramecium, a ciliated protozoan

Cilia Euplotes