KINGDOM PROTISTA
(Chapters 26 & 27)
1. Kingdom Protista is a diverse group of eukaryotic organisms. Protists may
resemble animals, plants, or fungi depending on where they get their food
energy. Species vary: unicellular to multicellular & microscopic to large.
2. Animal-like protists are called Protozoa. These species are unicellular, &
heterotrophic. They feed on other organisms or dead organic matter & are
found in fresh & salt water, moist soil, & as disease-causing parasites in animals.
a) ameoba (Phylum Rhizopoda) - move & capture food by extending their
cell membrane to form pseudopodia - enzymes in food vacuoles digest
food - contractile vacuoles collect & expel water - binary fission
b) ciliate (Phylum Ciliophora) - short, hair-like extensions cover surface - binary fission or conjugation (paramecium)
c) flagellate (Phylum Zoomastigina) - 1 or more long extensions called flagella
whip from side to side (African Sleeping Sickness/termite mutualism)
d) sporozoa (Phylum Sporozoa) - produce reproductive cells called spores - all
species are internal parasites in blood or intestines of animals. (malaria)
3. Plant-like protists are the autotrophic algae. Their pigments produce color
variety. (red, green, gold, blue, purple, & brown) May be unicellular or
multicellular. Floating on or near the surfaces of oceans, ponds, & lakes, they
are known as phytoplankton. They are the basis of aquatic food chains &
produce most of Earth’s oxygen.
4. Algae species include:
a) diatoms (Phylum Bacillariophyta) - covered with hard silica shells that can
be harvested from the ocean floor & used in water filters, abrasives,
sparkle in road paint & nail polish
b) dinoflagellates (Phylum Dinoflagellata) - thick plates of cellulose form cell
walls into many shapes - flagella create a slow spinning movement - some species are bioluminescent & toxic species include red tide
c) red algae (Phylum Rhodophyta) & brown algae (Phylum Phaeophyta) -
multicellular seaweeds lack true roots, stems, & leaves
d) green algae (Phylum Chlorophyta) - 7000+ diverse species - can
be unicellular (Chlamydomonas), colonial (Volvox), or multicellular (Spirogyra)
5. Slime molds, water molds, & downy mildews are fungus-like protists. Some
species are unicellular & others multicellular. As heterotrophic decomposers.
they secrete enzymes onto food source to predigest it before absorption.
(damp places rich in nutrients (rotting logs, moist soil, water, & animal feces)