Kingdom Protista sometimes called the “Junk drawer” contains animal-like, plant-like and fungus-like organisms Plankton (zoo-/phyto-/myco)

Characteristics of Protists: Eukaryotic cells Most are unicellular, but some are “colonial” (many identical cells) Most are motile (some sessile) Most are aquatic (some terrestrial) Reproduce asexually (some conjugate)

Animal-like Protists Zooplankton (Protozoans) All are heterotrophic Classified based on how they move: Sarcodines – move by changing their shape Ciliates – move by rhythmic beating of cilia Flagellates – move by long flagella

Zooplankton Sarcodines – Ciliates -

Zooplankton Flagellates -

Zooplankton We will study 2 examples of Zooplankton Amoeba (sarcodine) Paramecium (ciliate)

Sarcodines Amoeba proteus Phylum Sarcodina Movement – formation of Pseudopods - cytoplasm is in constant motion, pushing against the plasma membrane

Amoeba in Action

Amoeba Food – heterotrophic and feed by Phagocytosis Reproduction – Binary fission Special structures Pseudopods – “false feet” Contractile vacuole – maintain homeostasis Food vacuole

Amoeba

Ciliates Paramecium caudatum Phylum Ciliophora Movement – swim by beating cilia Paramecium movement Food – ingest food using the following structures Oral groove – cilia – cytostome – gullet – food vacuole Paramecium feeding

Paramecium Reproduction – Binary fission - Conjugation – 2 paramecia line up their oral grooves and swap micronuclei.

Paramecium Special structures: Macronucleus – controls metabolism Micronucleus - involved in conjugation Contractile vacuoles – maintains (here it is) homeostasis Ingestion structures Anal pore – excretion of wastes Trichocysts – defense mechanism

Paramecium