Biology Chapter 20 Notes Kingdom Protozoa Protist any organism that is not a plant, animal, fungus, or prokaryote. Eukaryotes Most difficult group to classify All can reproduce asexually Three categories: Animallike protists, Plantlike Protists, Fungaslike Protist (1) Animallike protists sometimes known as Protozoans (it confuses people) Heterotrophs Unicellular Divisions based on movement Zooflagellates swim with flagella Sarcodines move by extension of their cytoplasm Ciliates move by use of cilia Sporozoans do not move at all Zooflagellates Swim with flagella Live in wet locations lakes, streams, host bodies Absorb nutrients through their cellular membrane In the case of water body Zooflagellates, absorb decomposing material In the case of host body, absorb nutrients inside another organism African Sleeping Sickness Zooflagellate Trypanosoma spread by tsetse fly in Africa Chills, rashes, and can infect neurons, resulting in deep, sometimes fatal sleep Gardia Zooflagellate can be found in clear water, causes severe diarrhea & digestion Problems. This is why hikers boil or treat water from streams Sarcodines Amoeboid movement movement by cytoplasmic projections called pseudopods Cytoplasm streams into the pseudopod and the cell follows. Example: Amoeba Use pseudopods for feeding Food is engulfed by pseudopods Engulfed food is in a structure called a food vacuole Enzymes digest the nutrients and they are released from the vacuole into the cell Ameobic Dysentery type of sarcodine passed through contaminated drinking water Severe diarrhea and sometimes extensive bleeding of the intestine
Also Examples of Sarcodines but do not need to be memorized: Foraminifera ocean sarcodines that secrete calcium carbonate (CaCO3) So numerous they created the White Chalk Cliffs of Dover Heliozoa Thin pikes of cytoplasm project from the silica shell of this Sarcodine. The result is a sparkly, spiky, sphere like the sun (helios) Ciliates Cilia short hair-like projections used for locomotion (many tiny oars rowing the cell) Found in freshwater and saltwater Freshwater problem: osmosis causes water to enter the cell Solution: contractile vacuole contracts, pumping water out of the cell Most possess two types of nuclei one macronucleus, one or more micronuclei Micronuclei hold reserve copy of the cell genes and is used in conjugation Many use cilia to swipe food into a gullet that ends in a food vacuole. When filled, the food vacuole fuses with lysosomes, food is digested/released Example: Paramecium this is the only organism where you must know the parts Pellicle - Highly organized cell membranes with trichocysts underneath Trichocyst small bottle-shaped structures used for defense When Paramecium is threatened the trichocysts project out in spiky defense 1. Cilia 2. Pellicle ridged membrane structure that keeps Paramecium s shape 3. Macronucleus 4. Micronucleus 5. Contractile Vacuole 6. Oral Groove 7. Gullet 8. Food vacuole 9. Anal pore 10. Trichocyst You do not need to know 11. Ectoplasm 12. Endoplasm Sporozoans Do not move on their own All are parasitic Reproduce by means of sporozites Malaria Sporozoan - Plasmodium carried by mosquitoes, infects liver, then infects red blood cells Bursting red blood cells occur every 24 hours causing chills and fever Trychonympha live in Termite s guts and make it possible for them to digest wood
(2) Plantlike protists Unicellular Algae Contain chlorophyll and pigments Many are highly motile Common in both salt water and freshwater Classified by type of pigments used for photosynthesis Chlorophyll has different types that absorb different wavelengths Accessory pigments that absorb different wavelengths than chlorophyll Euglenophytes, Chrysophytes, Diatoms, and Dinoflagellates Euglenophytes 2 flagella, chloroplasts, but do NOT have a cell wall Main organism Euglena Ponds and lakes all over the world Two flagella emerge from gullet at the end of the cell Reddish pigments make an eyespot site of photosynthesis NO cell wall, but cell membrane has ridged structure called a pellicle Chrysophytes Yellow-green algae and golden brown algae Chloroplasts contain bright yellow pigment Store food in the form of oil. Diatoms Cell walls rich in silicon and shiny Shaped like a pillbox, or petri dish with fine lines and patterns, look like crystals Make up a large part of beech sand, used to filter water Dinoflagellates Pyrrophyta 50% are photosynthetic, 50% heterotrophs Two flagella wrapped around itself in grooves in plated cell wall Many are luminescent and some can light up the ocean a blue, fluorescent color Phytoplankton Small, photosynthetic organisms found near the surface of the ocean that carry out 50% of the earth s oxygen production. Food source for fish, shrimp, whales, etc. Algal Bloom Protists, such as many of the unicellular algae absorb nutrients directly from the environment and use decayed material When amounts of sewage or fertilizer are excessive, populations of unicellular algae
grow into enormous masses known as blooms These large numbers deplete the water of nutrients and oxygen and then die. Decomposition of the cells also removes oxygen, killing anything living in the water Euglenophyta (Euglena) is famous for this Red Tide. Granyaulax and Karenia (dinoflagellates) have also caused blooms in the ocean while producing a toxin that can end up in filter feeding shellfish, such as clams. The toxin can make humans very sick and even cause deatthe red color gives this algal bloom the name red tide (Note: you do not have to memorize the species names) (2) Plantlike Protists (continued) - Multicellular Algae Algae that are multicellular and have a life-cycle similar to plants Many have chlorophyll and photosynthesis like plants Usually have highly specialized tissue Three phyla red algae, brown algae, and green algae Red Algae Can live deep in the ocean where there is minimal light due to pigments Chlorophyll a and red accessory pigments Especially good at absorbing blue light, able to live in lowest light conditions Color ranges can be green, purple, or reddish black Help form coral reefs and provide nutrients for other reef organisms Brown Algae Chlorophyll a and chlorophyll c and a brown accessory pigment. Dark, yellow brownish color Most are marine and like cool or cold waters Include giant kelp, largest algae that grows 60 meters in length Another brown algae, Sargassum, forms large mats on the ocean Famous for the Sargasso Sea so large it looks like a seaweed ocean Often floats up on the beaches in Florida, Alabama, etc. Green Algae Cell wall is similar to plants, contain cellulose Cholorphyll a and b similar to land plants Store nutrients as starch similar to land plants Found in fresh and salt water. Can live as a single cell, form colonies, or be multicellular Colony group of similar cells that are joined but do not have specialized structures Alternation of Generation - Life Cycle includes diploid and haploid generation Any algae that is part of the sporophyte generation is diploid 2N Any algae that is part of the gametophyte generation is haploid N Example: Sea Lettuce
Uses for Algae 25% of Oxygen on earth is produced by Algae Chemicals from algae treat arthritic, ulcers, high blood pressure, etc.. Eaten in sushi Nori that wraps suchi is dried Poryphera Algin used as a thickener in ice cream, pudding, salad dressing, etc. Agar is used in laboratories everywhere to grow microorganisms. (3) Fungaslike Protists. - Molds Live in damp, nutrient-rich envioronments Absorb food through cell membranes Heterotrophs important decomposers on forest floor and compost Have centrioles fungi do not Do NOT have chitin in membranes all fungi do Types cellular slime molds, acellular slime mold, water molds Cellular Slime Molds Key to recycling organics materials in forests and compost piles Cells remain separated by cell membranes during all phases of life cycle When conditions are good cellular slime molds act like amoebas When conditions are poor they form spores 1. Individual cells send out chemical signals calling other cells 2. Within days, thousands have come together, forming a slug-like colony 3. The colony migrates for a few inches and stops. 4. The colony produces a fruiting body reproductive structure that creates spores 5. The spores are scattered, each one containing a single cell. Acellular Slime Molds Also recycle materials in environments like the forest floor 1. Cells are separated and act like amoebas, they are diploid (2N) 2. Cells aggregate to forma a colony and their cells FUSE 3. Plasmodium - A single structure with many nuclei created by the fused mold cells. these can be as big as a few feet! The nuclei are diploid (2N) 4. Sporangia small fruiting bodies grow from plasmodium 5. Sporangia cells go through meiosis producing haploid (N) spores 6. Spores scatter and germinate into flagellated haploid (N) cells 7. Two flagellated haploid (N) cells join and form a diploid (2N) zygotes 8. Diploid zygotes are the cells from step 1 the cycle repeats (you do not need to know the steps, just know plasmodium and sporangia)
Water mold Thrive on dead or decaying matter in water Some are plant parasites on land many cause blights on farm crops Produce filaments called hyphae like fungi, but do not have walls between the cells unlike fungi Cell walls made of cellulose unlike fungi Produce motile spores unlike fungi Alternation of Generation: Reproduce Asexually - zoosporangium 1. Part of the water mold hyphae develops into a diploid (2N) Zoosporangium (spore case) 2. Each spore case contains a single spore and have flagella (2N) 3. The spores are released, swim away, and grows into a new hyphae Reproduces Sexually oogonium and antheridium 1. Hyphae creates two different specialized structures, antheridium, oogonium 2. Antheridium goes through meiosis and produces haploid (N) male nuclei 3. Oogonium goes through meiosis and produces haploid (N) female nuclei 4. Both types of nuclei fuse to form a diploid zygote (2N) (Know the underlined words but you do not have to know the details) Water Molds are very important decomposers but they are also famous for plant disease. Most famous is the potato famine in Ireland caused by a potato blight water mold.