Kingdom Protista

Protists first appeared in the fossil records about 1 Protists first appeared in the fossil records about 1.5 billion years ago. Demonstrate an important evolutionary advancement, a membrane bound nucleus. Contain organelles such as ribsomes, mitochondria, and lysosomes. These structures provide a more efficient method of using available nutrients. Members of the Kingdom Protista are the simplest of the eukaryotes.

Background Protists can be unicellular, multicellular or colonial. Reproduce sexually and asexually. Require an aquatic environment. Some move around and act like animals, others perform photosynthesis like plants, and still others seem to "think" they're fungi!

Why are They Important? Autotrophic protists, like phytoplankton, produce a significant portion of the Earth’s oxygen. Play an important role in the carbon cycle. Important producers and consumers in food chains. Act as a road map for evolution!

Kingdom Protista

Protozoans

Phylum Sarcodina - Amoeba Thrive in fresh water, salt water and soil. Many are motile, with pseudopods used for locomotion. Few parasitic species found in animal intestines.

Phylum Ciliophora - Paramecium Most complex and advanced of the protozoans. Have hairlike structures called cilia which are used for movement and in feeding. Reproduce through binary fission and conjugation.

Phylum Mastigophora Flagellates move by means of flagella and are found in salt and fresh water.Most are parasitic and cause disease in animals. Asexual reproduction Form cysts that allow them to be spread from host to host.

Phylum Sporozoa Lack means of independent locomotion. Exclusively parasitic. Depend entirely upon the body fluids of their hosts for movement. Have a spore like stage.

Plantlike Protists

Phylum Chrysophyta - Diatoms Fresh and salt water Autotrophic, contain chlorophyll. Many are encased in shells or skeletons.

Phylum Pyrrophyta - Dinoflagellates Autotrophs, contain chlorophyll and red pigments. Can contaminate shell fish.

Phylum Euglenophyta - Euglena Both heterotrophic and autotrophic. Have an eye spot which is sensitive to light. Reproduce asexually and asexually. Evolutionary link between plants and animals.

Overview of Animal like Protists

Plantlike Protists

Assignment How do moneran and protist cells differ? What roles do protists play in ecosystems? Copy and complete the following chart by placing a check mark in the appropriate column. chart