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The Kingdom Protista Chapter 20 What is a Protist? Any organism that is not a plant, an animal, a fungus, or prokaryote. Are eukaryotes that are not members of the kingdoms, Plantae, Animalia, or Fungi Classification of Protists Protists are so diverse that many biologists suggest that they should be broken up into several kingdoms. Unfortunately, biologist do not agree on how to classify the protists. Classification of Protists Section 20-1 Protists are classified by Animallike Plantlike which which which Take in food from the environment Produce food by photosynthesis Obtain food by external digestion Funguslike which include Decomposers Parasites Animallike Protists: Protozoans 4 phyla of the animallike protists Distinguished from one another by their means of movement Zooflagellates-move by flagella ex. Trychonympha(termite), Trypanosoma(Tse Tse Fly) Sarcodines-move by pseudopods ex. amoeba Ciliates-move by cilia ex. paramecium Sporozoans-no movement, parasites ex. plasmodium Zooflagellates Animallike protists that swim using a flagella Most have 1-2 flagella Live in lakes & streams, where they absorb nutrients from decaying matter Some live within bodies of other organisms, taking advantage of the food from larger organisms Can reproduce by asexual and sexual reproduction Sarcodines Move via temporary cytoplasmic projections known as pseudopods Amoebas Surround food and form a food vacuole Amoeba Contractile vacuole Pseudopods Nucleus Food vacuole Ciliates Contain short hairlike projections called cilia Use cilia for feeding & movement Found in both fresh & salt water Ciliates Trichocysts Lysosomes Oral groove Gullet Anal pore Contractile vacuole Micronucleus Macronucleus Food vacuoles Cilia Sporozoans Do not move on their own & are parasitic Animallike Protists & Disease Malaria African sleeping sickness Amebic dysentery Malaria One of the world’s most serious infectious disease 2 million people still die from malaria every year Carried by the female Anopheles mosquito Cycle of Malaria (pg. 503) Symptoms & Treatment of Malaria Severe chills Fever There are a number of vaccines against malaria but to date most are only partially effective Controlling mosquitoes is the best method to controlling malaria African Sleeping Sickness Zooflagellates of the genus Trypanosoma Spread by the bite of an insect known as the tsetse fly Symptoms Begin to show 1 to 4 weeks after bite Chills Rashes Infect nerve cells: severe damage causes some individuals to lose consciousness, lapsing into a deep and sometimes fatal sleep Treatment Hospitalization Medications Follow-ups for 2 years Amebic Dysentery Common in areas with poor sanitation Severe diarrhea Caused by an organism that looks like the harmless amoebas Entamoeba, a parasite spread by contaminated drinking water Attacks the wall of the intestine, causing extensive bleeding Amebic Dysentery Can also occur in the crystal-clear mountain streams Caused by another flagellated pathogen, Giardia Giardia produces tough, microscopic-size cysts that can be killed only be boiling water thoroughly or by adding iodine to the water Causes severe diarrhea and digestive system problems. Ecology of Animallike Protists Essential roles in the living world Live symbiotically with other organisms Recycle nutrients by breaking down dead organic matter Live in seas and lakes & are a part of the food chain Trichonympha Zooflagellate that lives within the digestive systems of termites Makes it possible for termites to eat wood Termites do not have an enzyme to breakdown wood The Trichonympha does it for them Homework Guided Reading Worksheets 20-1 20-2 Due Wednesday, February 16th Plant-Like Protists Commonly called Algae Contain chlorophyll and carries out photosynthesis Unicellular Algae-classified by pigments Phylum Euglenophyta 2 flagella but no cell wall Phylum Chrysophyta Gold-colored chloroplast Phylum Bacillariophyta Called diatoms Cell walls contain silicon Phylum Pyrrophyta Called dinoflagellates Draw a Euglena see p. 507, Figure 20-10) Ecology of Unicellular Algae Make up most of phytoplankton Small photosynthetic organisms near surface of ocean ½ of all photosynthesis on Earth is performed by the algae Source of nourishment for small fish Algal Blooms and “Red Tides Help recycle sewage and fertilizer Grow too much, deplete nutrients, die, rid water of oxygen, choke out fish life Can produce toxins, eaten by clams and shellfish, eaten by humans and cause death Multicellular Algae (mostly) Phylum Rhodophyta Red Algae Phylum Phaeophyta Brown Algae Phylum Chlorophyta Green Algae Draw Brown Algae see p. 511, Figure 20-15 Reproduction Alternation of Generations Life cycle includes both haploid and diploid generation Enables them to survive unfavorable conditions Analyzing Data Pg. 508 Questions 1-4 Fungus-Like Protists Like fungi-absorb nutrients from dead or decaying organic matter Different from fungi-have centrioles and lack chitin cell walls Funguslike Phyla Phylum Acrasiomycota Slime mold Phylum Myxomycota Acellular slime mold Phylum Oomycota Water mold (white mold on dead fish) The Great Potato Famine Phytophthora infestans (Phylum Oomycete) destroyed 60% of the potatoes in Ireland in 1845 Between 1845 and 1851 at least one million Irish people died of starvation or disease One million Irish emigrated to the U.S. and other countries Homework Guided Reading Worksheets 20-3 20-4 20-5 Preparing for TAKS pg. 525 1-4 Due Friday, February 18th