Biology I—Ch 20 Protists -Protist: any organism that is not a plant, animal, fungus, Or prokaryote -3 major types 1. Animal-like 2. Plant-like 3. Fungus-like Animal-like protists -4 phyla 1. Phylum Zoomastigina -animal-like protists that swim using a flagella -generally able to absorb food through their cell membranes -found in lakes, streams, inside bodies of other organisms -most reproduce asexually by mitosis -some can perform a type of sexual reproduction as well

2. Phylum Sarcodina -animal-like protists that use pseudopods for feeding and movement -amoebas in this group -Foraminiferans secrete calcium carbonate -white chalk cliffs of Dover, England formed from large deposits of foraminiferan skeletons 3. Phylum Ciliophora -use cilia for feeding and movement -found in fresh and salt water -most free-living -Paramecium -can undergo conjugation (sexual reproduction)

4. Phylum Sporozoa -do not move on their own and are parasitic -many have complex life cycles that involve more than one host -Plasmodium causes malaria -spread by the Anopheles mosquitoes

Disease and Animal-like protists -Trypanosoma is a zooflagellate that causes African Sleeping Sickness -spread by the tsetse fly -causes fever, chills, and rashes -infects nerve cells -can cause severe damage to nervous system causing some to lose consciousness, lapsing into a deep and sometimes fatal sleep—disease name origin -Entamoeba causes amoebic dysentary -live in intestines -cause severe bleeding -Giardia can cause severe diarrhea

Ch 20 Sections 2-3—Plantlike Protists -Phytoplankton—small, photosynthetic organisms found near the surface Of the water—often unicellular -4 phyla 1. Phylum Euglenophyta -plant-like protists that have 2 flagella, but no cell wall -found in ponds and lakes -can be autotrophic or heterotrophic -Pellicle: tough, flexible cell membrane -reproduce asexually by binary fission 2. Phylum Chrysophyta -yellow-green and golden-brown algae -have gold-colored chloroplasts -cell walls contain pectin instead of cellulose -some contain both pectin and cellulose -store food as oil rather than starch -reproduce sexually and asexually

3. Phylum Bacillariophyta—Diatoms -produce thin, delicate cell walls rich in silicon 4. Phylum Pyrrophyta—Dinoflagellates -”fire plants” -about ½ autotrophic and ½ heterotrophic -most reproduce asexually by binary fission -many are bioluminscent -some species cause “red tides” -blooms off east coast of US -produce toxins that kill organisms in the water -eating shell fish from infected water can cause serious illness, paralysis, and even death in humans and fish

-Multicellular Algae -3 phyla 1. Phylum Rhodophyta—red algae -able to live at great depths due to the pigment phycobilin -phycobilins absorb blue light which penetrates the furthest down into the ocean -found in waters from polar regions to the tropics -grow from ocean’s surface up to 260 m deep 2. Phylum Phaeophyta—brown algae -contain chlorophyll and a brown pigment fucoxanthin -largest and most complex algae -most found in cool shallow coastal waters of temperate or arctic areas of the ocean -giant kelp--grow up to 60 m in length -Sargassum form huge floating mats

3. Phylum Chlorophyta—green algae -contain chlorophyll and cell walls in cell walls -found in fresh and salt water -unicellular, colonial, and multicellular -Unicellular: Chlamydomonas -Colonial: volvox--500-50,000 cells arranged to form hollow spheres -spirogyra forms long threadlike colonies called filaments -Multicellular: Ulva found along rocky sea coasts

Ch 20 Section 3—Fungus-like protists -heterotrophs that absorb nutrients from dead or decaying organic Matter -lack chitin in cell walls -3 phyla Phylum Acrasiomycota—Cellular Slime Molds -spend most of their lives as free-living cells that are not easily distinguishable from soil amoebas -when food supplies get low single cells come together to form a large sluglike colony that produces spores -each spore gives rise to another amoeba-like cell that starts the cycle over

Phylum Myxomycota—Acellular Slime Molds -begin life as a single amoeba-like cell -come together to form a plasmodium -Plasmodium: a single structure with many nuclei -may grow as large as several meters in diameter -produce haploid spores by meiosis -form amoeba-like cells or flagellated cells -flagellated cells come together to produce diploid zygotes that repeat the cycle

Phylum Oomycota—Water Molds -thrive on dead or decaying organic matter in water and some are Plant parasites on land -cell walls contain cellulose and motile spores -have both sexual and asexual reproduction -Phytophthera infestins caused the potato famine in Ireland -in 1845 as much as 60% of the potato crop was lost -in 1846 nearly the entire crop was lost -hit poorest farmers the hardest -between 1845-1851 at least 1 million Irish people died of Starvation or disease -also more than 1 million people emigrated from Ireland to the U.S. and other countries