Paramecium (many species) is free living Animal-Like Protists Heterotrophic Classified by means of locomotion: flagella, cilia, pseudopods, or none (sessile) Many free living, some parasites of humans and animals Paramecium (many species) is free living

Animal-Like Protists Phylum Protozoa Locomotion by pseudopodia  cytoplasmic streaming/cyclosis  amoeboid movement Prey on bacteria, ingest food particles in water using pseudopodia  vesicle, intracellular digestion Subphylum Sarcodina - amoebas: freshwater, marine or soil; some have a test/shell around cell membrane Subphylum Mycetozoa – some have glassy shells (radiolarians)

Testate Amoebas Simple tests (or shells) are made by either secretion or by the agglutination of foreign material or a combination of both. Environmental changes can be determined by analyzing the composition of tests, including fossil tests, which may indicate past climatic conditions.

Radiolarian (marine amoeba) shells

Animal-Like Protists Phylum Ciliophora Locomotion by cilia Asexual reproduction – binary fission Most elaborate organelles of any protist: Macronucleus that controls cell functions Micronucleus exchanged through conjugation (sexual reproduction) pellicle (elastic layer of protein) surrouding cell membrane Food acquisition: oral groove  mouth pore  gullet  food vacuoles Excretion: anal pore  contractile vacuole

Animal-Like Protists Phylum Sarcomastigophora Trypanosomes in human blood Tsetse fly (vector) One or more flagella Subphylum Mastigophora – many free living, some parasites  genus Trypanosoma Infect blood in many vertebrates Transmitted by insect vectors Ex.: African sleeping sickness, caused by two species of trypanosomes, transmitted by tse-tse fly  fever, lethargy, eventual coma, death; Giardia – found in fresh water  gastrointestinal disease

Giardia lamblia causes giardiasis, an intestinal infection Found in freshwater – streams & rivers Cysts carried in animal feces

Animal-Like Protists Phylum Apicomplexa (former sporozoans) Plasmodium faciparum no adaptations for locomotion  all animal parasites Apical complex = organelles specialized for entry into host cells/tissues Complex life cyles with sexual and asexual stages, often more than one host Plasmodium – mosquito vector  malaria Toxoplasma gondii – affects developing fetuses, newborns Cryptosporidium – found in water, animal feces  gastrointestinal disease

Malaria life cycle on UTube Anopheles mosquito vector Malaria life cycle on UTube Malaria 350–500 million cases / year, killing one to three million people

Fungus-Like Protists Slime Molds & Water Molds Uni- or multi-cellular, all heterotrophic Saprophytic, some parasitic

Fungus-Like Protists Phylum Myxomycota – Plasmodial Slime Molds Feeding stage = Plasmodium, a multinucleated (2n) mass of cytoplasm Amoeboid movement by cytoplasmic streaming phagocytosis of decaying matter Reproductive state = Fruiting bodies produce haploid spores by meiosis Spores produce haploid (n) reproductive cells that fuse (2n) mitosis w/o cytokinesis  multinucleated plasmodium (unicellular)

Physarum life cycle

Fungus-Like Protists Phylum Dictyostelida – Cellular Slime Molds Individual haploid cells live independently Scarcity of food triggers release of chemical that attract others Many cells gather to form a multi-cellular pseudoplasmodium – (each cell retains its membrane)  develops fruiting bodies  haploid spores  new independent haploid cells

How do cellular slime molds differ from plasmodial slime molds?

Fungus-Like Protists Phylum Oomycota – Water Molds Asexual reproduction -- flagellated zoospores  threadlike cells Sexual reproduction – egg and sperm produced  fertilization tubes  zygote  threadlike cells Water mold on dead mayfly larva

Fungus-Like Protists Phylum Chytridiomycota – Water Molds Healthy Tasmanian frog Fungus-Like Protists Phylum Chytridiomycota – Water Molds Most unicellular, parasitic Make flagellated gametes and zoospores Chitin in cell walls, filamentous cells, enzymes and biochemistry similar to fungi  some classify them in kingdom Fungi may be a transitional form between protists and fungi Infected frog Chytrid (pronounced kit-rid) fungus (Batrachochytrium dendrobatidis) causes the disease known as chytridiomycosis or chytrid infection which currently threatens Tasmania’s native amphibians. The fungus infects the skin of frogs destroying its structure and function, and can ultimately cause death. Sporadic deaths occur in some frog populations, and 100 per cent mortality occurs in other populations. Chytrid infection has been devastating to frog species causing extinctions worldwide. The international trade of frogs probably brought the fungus to Australia from Africa. The disease has now been recorded in four regions in Australia - the east coast, southwest Western Australia, Adelaide, and more recently Tasmania. In mainland Australia chytrid has caused the extinction of one frog species, and has been associated with the extinction of three other species. In addition, the threatened species status of others frogs has worsened through severe declines in numbers. Chytrid (microscopic)