Kingdom Protista Protists u Protists are all around

Kingdom Protista

Protists u Protists are all around us, but we seldom notice them. u Protists are part of nearly every type of moist habitat on Earth from high mountain peaks and rain forests to rivers, lakes, and oceans. u They form the foundation of many ecosystems.

Protist Diversity Kingdom Protista is the most diverse of the six kingdoms. u The more than 200, 000 species come in many different shapes, sizes and colors. u They may be unicellular or multicellular. u Some are jellylike blobs; others have shells or cell walls. u

So What IS a Protist? u Basically, any organism that is not a plant, an animal, a fungus, or a prokaryote. u ALL are eukaryotic. u MOST are unicellular. u Multicellular protists are grouped in this kingdom because they are very similar to unicellular protists.

Three General Groups u Animal-like Protists—unicellular heterotrophs, most are mobile u Plantlike Protists— photosynthetic autotrophs u Funguslike Protists—look like fungi and function as decomposers u Problem: Categories do not reflect phylogeny

Protozoans: Animal-like Protists u Unicellular u Heterotrophs u Feed on other organisms or dead organic matter u Grouped into phyla by the way they move u Some are nonmotile and live as parasites

Sarcodines: Bloblike Protozoans Amoebas, foraminiferans, and heliozoans u Most are marine u Some have shells u Most reproduce asexually u Some can form cysts to survive extreme conditions u

Amoeba Features Move and feed with pseudopodia No cell wall No definite shape Contains food vacuoles to store food

Entamoeba: Sarcodine Causes Amebic Dysentery u Cysts form and are passed through feces u Contaminated water, food, dishes spread the disease u Excessive bleeding u “Don’t drink the water!” u

Zooflagellates: Protozoans with Flagella Move by whipping one or more flagella from side to side u Absorb food through their cell membranes u May live in lakes and streams u u Trichomonas vaginalis causes an STD

Trichonympha: Zooflagellate Lives in the intestines of termites u Help digest the cellulose in wood u Example of mutualism u

Trypanosoma: Zooflagellate Cause African Sleeping Sickness u Carried by the tsetse fly u Chills and rashes u Some lapse into a deep, sometimes fatal sleep u

Ciliates: Protozoans with Cilia Considered the most complex protozoans u Move by beating the cilia that cover their bodies u Found in every kind of aquatic habitat u

Paramecium Structures u Macronucleus – “working library” of DNA u Micronucleus – “reserve copy” of DNA u Trichocyst – bottle-shaped structure for defense u Contractile Vacuole – removes excess water u Gullet – food goes in u Anal Pore – waste materials leave

Sporozoans: Parasitic Protozoans u Parasitic u Nonmotile u Many produce spores u Toxoplasma – danger for pregnant women

Plasmodium: Sporozoan Causes malaria u Carried by the Anopheles mosquito u Fever, severe chills, headache, fatigue u Not all strains can be treated u There is no completely effective vaccine u

Algae: Plantlike Protists u Photosynthetic u No roots, stems or leaves u Contain chlorophyll and other pigments u Pigments important in classification u Major producers of nutrients in aquatic ecosystems u Produce more than half of the

Euglenoids: Plants or Animals? Autotrophs as well as heterotrophs u Unicellular u Flexible pellicle u Contain chlorophyll u Move with flagella u Can ingest food u Red eyespot u

Diatoms: Golden Algae Unicellular u Photosynthetic u Marine and freshwater u Silica shells are like pillboxes with lids u Each species has its own unique shape u Asexual and sexual reproduction u

Dinoflagellates: Spinning Algae Unicellular u Cell walls made of cellulose plates u Two flagella cause spinning when they beat u Most are marine u Some symbiotic u Some bioluminescent u Some produce toxins u

RED TIDES u u u One species of dinoflagellate produces an extremely strong nerve toxin that can be lethal Summer population explosions can turns the ocean red and kill tons of fish Harvesting of shellfish is banned during these times

Red Algae: Red Seaweeds Multicellular u Marine u Tropical waters or along rocky coasts in colder water u Attach to rocks with holdfasts u Contain red and blue pigments for photosynthesis at low light levels u

Brown Algae: Kelp and Friends Almost all marine u Almost all cool water u Largest is kelp u Use holdfasts u Many have air bladders to help them float u

Green Algae: The Most Diverse Major pigment is chlorophyll u Most are freshwater u Wide variety of forms u Complex reproductive cycles u Many biologists feel ancient green algae were the ancestors of plants u

Fungus-like Protists u Form delicate, netlike structures on the surface of their food supplies u Obtain energy by decomposing organic materials u Two phyla contain slime molds, and a third phylum contains water molds and downy mildews

Slime Molds Many are beautifully colored u Live in cool, moist places on organic matter u Cellular or plasmodial u Reproduce with spores u Able to move during much of their lifecycle u

Water Molds & Downy Mildews Most live in water or moist places u Some feed on dead organisms u Some parasitize plants u Water molds produce flagellated reproductive cells u