PROTISTS Domains Classification Review Domain Kingdom Phylum Class

PROTISTS

Domains

Classification Review • • Domain Kingdom Phylum Class Order Family Genus Species

Protists • Protists: • Unicellular eukaryotic organisms – very diverse • Over 115, 000 species • Eukaryotic cells - contain membrane-bound organelles (particularly mitichondria & chloroplasts) • Three major classes of protists (old system but still used) – – – Animal-like protists Plant-like protists Fungus-like protists

First Eukaryotes • 1. 5 billion years ago

Animal-like Protists • Ciliates (Cilia bearing protists) – Have cilia (short hairlike structures) on their plasma membranes

Paramecium • Important features: • Have 2 nuclei • Macronucleus • Micronucleus • Feed by forcing H 2 O into Gullet forming food vacuoles • Excrete wastes through anal pore • Excrete excess water through use of contractile vacuoles

More ciliates

Phylum Sporozoa • Usually parasitic in nature • Example is Plasmodia which causes malaria. – One of the most deadly diseases to man – Malaria is transmitted by the Anopheles mosquito.

Lifecycle of Plasmodia

Phylum Sarcodina Protists with false feet • Use extensions of cytoplasm to move and feed. • Extensions are called pseudopods (false feet)

Amoebas

More amoebas

Plant-like Protists • Are usually photosynthetic, and also heterotrophic. • Most are unicellular, most are motile

• Example is euglena. • Has a flagellum, is motile • Is both heterotrophic & autotrophic

Euglena

Dinoflagellates • Have 2 flagella for motility • • Often have a cellulose covering

Diatoms • Most abundant form of marine algae. • Form silicon (glass) shells to protect themselves

Red Algae (Rhodophyta) • Red Algae (Rhodophyta) • Red Tide Red algeal bloom

Brown Algae (Rhodophyta) • Brown Algae (Rhodophyta) – Most Plant-like of all algae. – Include kelps – Can grow to huge sizes (100') –. Giant Kelp Forest

Fungus like Protists: • Fungus like Protists: – Act as decomposers – Often have a slimy appearance/texture, hence their name. – 3 types: • Plasmodial slime molds • Cellular slime molds • Water molds

Plasmodial Slime Molds • Plasmodial Slime Molds – Can grow very large, however, is still a single cell (with many nuclei) – Feeding stage is called a plasmodium. – Forms fruiting bodies under stress.

More slime molds

Cellular Slime Molds: • Exists a majority of its life cycle as an amoeba • In times of stress these amoebas unite to form a Pseudoplasmodium, which crawls to another location (slug form), and forms a fruiting body

Water molds: molds • Water molds: – Completely aquatic – Often decomposers – Sometimes parasitic Water mold attacking a fish