Protists

Protist Characteristics  Live in water  Eukaryotic  Most are unicellular, some are multicellular (algae)

Protist Characteristics  Some are autotrophic (can make own food); some are heterotrophic (cannot make own food) Amoeba eating paramecium (other protist) Photosynthetic euglena

Protist Characteristics  All can reproduce asexually (by mitosis or binary fission); some are capable of sexual reproduction (by conjugation) (Remember the different methods of asexual & sexual reproduction?) Asexual Reproduction Sexual Reproduction Binary fission Sexual intercourse BuddingPollination Regeneration Fragmentation

Sexual or Asexual? conjugation Binary fission

Protist Characteristics  Some have cells with contractile vacuole that help maintain homeostasis (can hold and expel fluid)

Protists can be: 1. Animal-like (protozoa) – absorb or gather/capture food Flagellates (or zooflagellates)- move by flagella Flagellates (or zooflagellates)- move by flagella Examples: ones that live in termite intestines, ones that cause African Sleeping SicknessExamples: ones that live in termite intestines, ones that cause African Sleeping Sickness

African Sleeping Sickness 1. Tsetse fly carries the parasitic protist inside, and infects the host when it bites, allowing the protist into the bloodstream. 2. The protist multiplies among red blood cells, and spreads throughout the body via the bloodstream.

More Animal-like Protists Sarcodines- uses pseudopods to move and capture prey Sarcodines- uses pseudopods to move and capture prey Example: amoebaExample: amoeba (pseudo means “false”, pod means “foot”) egallery/pondscum/protozoa/ amoeba/index.html egallery/pondscum/protozoa/ amoeba/index.html Brain-Eating Amoeba!

More Animal-like Protists  u.edu/moviegallery/po ndscum/protozoa/par amecium/index.html u.edu/moviegallery/po ndscum/protozoa/par amecium/index.html u.edu/moviegallery/po ndscum/protozoa/par amecium/index.html Ciliates- move/eat by cilia, has oral groove and anal pore Example: paramecium

More Animal-like Protists Sporozoans- parasitic, reproduces by spores Sporozoans- parasitic, reproduces by spores Example: plasmodium (causes malaria)Example: plasmodium (causes malaria) Plasmodium falciparum is carried by mosquitos, and injected into the host when they bite.

Protists can be: 2. Plant-like (algae)- contain chlorophyll and are photosynthetic Euglena- can make and consume food Euglena- can make and consume food allery/pondscum/protozoa/euglena/r ostrifera/index.html

More Plant-like Protists Diatoms- various shapes, cell walls of silicon, are used in toothpaste and scouring products Diatoms- various shapes, cell walls of silicon, are used in toothpaste and scouring products

More Plant-like Protists Dinoflagellates- have flagella; one example causes red tides Dinoflagellates- have flagella; one example causes red tides Pfiesteria piscicida causes red tides and fish kills

More Plant-like Protists Multicellular algae- green, brown, red Multicellular algae- green, brown, red

Protists can be: 3. Fungus-like- cell walls, absorb nutrients, reproduce by spores Slime molds Slime molds Watermolds Watermolds Example: Phytophthora infestans cause of potato famine in Ireland (1845 – 1852)Example: Phytophthora infestans cause of potato famine in Ireland (1845 – 1852)