Mader: Biology 8 th Ed. The Protists Chapter 22

Mader: Biology 8 th Ed. Outline General Biology Evolution Diversity – Green Algae – Red Algae – Brown Algae – Diatoms – Dinoflagellates Diversity – Euglenoids – Zooflagellates – Pseudopods – Ciliates – Sporozoans – Slime Molds – Water Molds

Mader: Biology 8 th Ed. General Biology of the Protists Protists are classified in the domain Eukarya and the kingdom Protista. – Most are unicellular, but have achieved a high level of complexity. – Asexual reproduction is common, but sexual reproduction can occur when the environment becomes stressful.  Spores  Cysts

Mader: Biology 8 th Ed. Origin of Eukaryotic Cell

Mader: Biology 8 th Ed. Evolution of Protists Complexity and diversity of protists makes them difficult to classify. – Cannot be classified as plants, animals, or fungi. – Has been suggested protists could be split into as many as a dozen kingdoms.

Mader: Biology 8 th Ed. Diversity of Protists Green Algae – Green algae (phylum Chlorophyta).  Chlamydomonas  Unicellular  Usually reproduces asexually  Forms spores and zoospores when growth conditions are unfavorable.

Mader: Biology 8 th Ed.

Green Algae – Spirogyra  Unbranched, filamentous alga found in masses on the surfaces of standing water.

Mader: Biology 8 th Ed. Green Algae – Multicellular  Ulva  Stoneworts  Chara

Mader: Biology 8 th Ed. Green Algae – Colonial  Volvox

Mader: Biology 8 th Ed. Red Algae Red Algae (phylum Rhodophyta) – Multicellular, and live mostly in warmer seawater.  Usually much smaller and more delicate than brown algae.  Economic Importance  Agar

Mader: Biology 8 th Ed. Brown Algae Brown Algae (phylum Phaeophyta) – Have chlorophylls a and c in their chloroplasts and a carotenoid pigment. – Often observed on rocky coasts in north temperate zone.  Seaweeds  Kelp  Fucus

Mader: Biology 8 th Ed. Brown Algae

Mader: Biology 8 th Ed. The Diatoms Diatoms (phylum Bacillariophyta) are the most numerous unicellular algae in the oceans. – Significant portion of phytoplankton. – Structure composed of two valves, with the larger valve acting as a lid. – Cell wall has outer layer of silica.

Mader: Biology 8 th Ed. The Dinoflagellates Most dinoflagellates (phylum Pyrrophyta) are unicellular. – Usually bounded by protective cellulose plates impregnated with silicates.  Typically contain two flagella.  Chloroplasts vary in color.  Usually reproduce asexually.  Some genera may cause red tide.

Mader: Biology 8 th Ed. Diatoms and Dinoflagellates

Mader: Biology 8 th Ed. The Euglenoids Euglenoids (phylum Euglenophyta) are small freshwater unicellular organisms. – Difficult to classify. – Have two flagella and an eyespot (shades a photoreceptor). – Bound by flexible pellicle.

Mader: Biology 8 th Ed. Euglena

Mader: Biology 8 th Ed. The Zooflagellates Zooflagellates (phylum Zoomastigophora) are colorless heterotrophs. – Most are symbiotic and many are parasitic. – Well known for causing various diseases in humans.  African sleeping sickness  Giardia lamblia

Mader: Biology 8 th Ed. Zooflagellates

Mader: Biology 8 th Ed. Protists with Pseudopods Pseudopods form when cytoplasm streams forward in a particular direction. – Amoeboids (phylum Rhizopoda) are protists that move and ingest their food with pseudopods.  Phagocytize food. – Foraminiferans (phylum Foraminifera) and radiolarians (phlyum Actinopoda) both have a skeleton (test).

Mader: Biology 8 th Ed. Protists with Pseudopods

Mader: Biology 8 th Ed. The Ciliates Ciliates (phylum Ciliophora) are most complex of the protozoans. – Hundreds of cilia beat in coordinated rhythm. – Most are holozoic. – Divide by transverse binary fission during asexual reproduction. – High level of diversity.

Mader: Biology 8 th Ed. Ciliates

Mader: Biology 8 th Ed. The Sporozoans Sporozoans (phylum Apicomplexa) are nonmotile parasites. – Most widespread human parasite is Plasmodium vivax, the cause of one form of malaria.

Mader: Biology 8 th Ed. Plasmodium vivax Life Cycle

Mader: Biology 8 th Ed. Slime Molds Plasmodial Slime Molds – (phylum Myxomycota) usually exist as a plasmodium.  Diploid, multinucleated, cytoplasmic mass enveloped by a slime sheath.  Sporangium produces spores. Cellular Slime Mold – (phylum Acrasiomycota) exists as individual amoeboid cells.

Mader: Biology 8 th Ed. Plasmodial Slime Molds

Mader: Biology 8 th Ed. Water Molds Water molds (phylum Oomycota) usually live in the water and form furry growths when they parasitize fish and decompose remains. – Have filamentous body with cell walls largely composed of cellulose.

Mader: Biology 8 th Ed. Review General Biology Evolution Diversity – Green Algae – Red Algae – Brown Algae – Diatoms – Dinoflagellates Diversity – Euglenoids – Zooflagellates – Pseudopods – Ciliates – Sporozoans – Slime Molds – Water Molds

Mader: Biology 8 th Ed.