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Kingdom Protista “the very first”. any organism that is not a plant, animal, fungus, or prokaryote (bacteria) Eukaryotes 1.5 billion years ago Classified by nutrition mode Animal like, Plant like, or Fungus like. Symbiosis.
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Kingdom Protista “the very first” • any organism that is not a plant, animal, fungus, or prokaryote (bacteria) • Eukaryotes • 1.5 billion years ago • Classified by nutrition mode • Animal like, Plant like, or Fungus like
Symbiosis • Relationship between organisms; one organism lives in or on the other • Organisms involved in relationship are called symbionts • 3 Types: • Mutualism: both symbionts benefit • Commensalism: one symbiont benefits; other is unaffected • Parasitism: one symbiont benefits; other is harmed
Vectors • Mechanically transfer parasite into host • Exs: tse-tse fly; female Anopheles mosquito • Carriers • Unaffected by disease
A) Animal-like Protists: Protozoans • Protozoa-”First animals” • Heterotrophs • Four phyla based on how they move • Unicellular
1) Phylum Zoomastigina: Zooflagellates • flagella • Absorb food through their cell membranes • Most reproduce asexually- binary fission • Live in lakes and streams or bodies of other organisms
Diseases • (African Sleeping Sickness) Trypanosomiasis • Trypanosoma – Tsetse Fly • Chills, rashes, nerve cell damage, coma
Termites and Trichonympha • Symbiotic (lives off food from termite) • Lives in termite gut • Contains cellulase that digests wood
2) Phylum Sarcondina: Sarcodines • Pseudopods “false foot” – cytoplasmic projections for eating and movement • Best known sarcodine - Amoeba • Amoeboid movement • Contractile and Food Vacuoles • Binary Fission • Foraminiferans – secrete calcium carbonate shells (chalk), accumulates on bottom of ocean.
ex. AMOEBA Contractile Vacuole (pump water) Pseudopods Nucleus Food Vacuole (store food)
Amebic Dysentery (Amebiasis) • Entamoeba-parasite spread by contaminated drinking water from poor sanitation • Severe diarrhea, attacks intestines, bleeding • Boiling water or iodine kills parasite
3) Phylum Ciliophora: Ciliates • Cilia – used for feeding and movement • Short, hair-like projections • Binary Fission and Conjugation (stress) • Best known ciliate – paramecium • Freshwater and saltwater • Trichocysts-stiff projections for defense of paramecium
Internal Anatomy • Two nuclei • Macronucleus • respiration, protein synthesis, and digestion. • Micronucleus • conjugation and contains a reserve copy of genes.
Trichocysts Oral groove Lysosomes Gullet Anal pore Contractile vacuole Micronucleus (conjugation) Macronucleus Foodvacuoles Cilia Figure 20-5 : ex. Paramecium
Nutrition • The cilia move food into the oral groove which leads to the gullet. • The food is forced into food vacuoles • Lysosomes break down the food with enzymes • Undigested food is removed through the anal pore • Contractile Vacuoles pump water in and out to maintain homeostasis
Conjugation New macronucleiform Macronucleus Micronucleus MEIOSIS Exchange ofmicronuclei Macronucleidisintegrate Genetically identical paramecium form *note: conjugation is a sexual process but NOT a form of sexual reproduction b/c no new individuals are formed. However, new combinations of genetic information are produced.
4) Phylum Sporozoa: Sporozoans • Parasitic protists • Parasites of many different organisms, including worms, fish, birds, and humans. • Many protists cause serious disease • Cannot move independently • Reproduce using sporozoites • A sporozoite can attach itself to a host and lives as a parasite.
Diseases • Malaria- sporozoan Plasmodium • Saliva of the female Anopheles mosquito • Sporozoites enter the bloodstream and the parasite infects the liver cells and red blood cells. • Red cells burst and release toxins into the bloodstream • 2 million people die each year from malaria • 800 million infected worldwide
B) Plant-like Protists: Unicellular Algae • Base of the food chain • “phytoplankton” • photosynthetic pigments • Autotrophs • 4 phyla based on the type of pigments they contain
1) Phylum Euglenophyta: Euglenophytes • two flagella • Lack a cell wall • Cell membrane called a pellicle • Chloroplasts – photosynthetic • Heterotrophic if no sunlight available • Eyespot – finds sunlight • Pellicle – tough and flexible
Euglena Fig. 20-10 Chloroplast Carbohydrate storage bodies Gullet Pellicle Contractile vacuole Nucleus Flagella Eyespot
2) Phylum Pyrrophyta “fire plants”: Dinoflagellates • 50% photosynthetic • 50% heterotrophs • 2 flagella • Plates made of cellulose for protection • Many are bioluminescent
Zooxanthellae (ex. of dinoflagellates) • Photosynthetic dinos that provide food for their host organism. • The host provides carbon dioxide and shelter. • Examples of host organisms: jellyfish, coral, clams
Red Tide • Water appears red due to “Algal Bloom” • Mass production of algae (due to excess nutrients) • Some dino species release toxins that affect nervous systems of fish • Ban on shellfishing
Paralytic Shellfish Poisoning • PSP is caused by a dino species that produces a toxin that is taken up by mollusks. • Eating these infected shellfish can cause serious illness, paralysis, or death
Pfiesteria-dinoflagellates *Causes lesions on the fish
3) Phylum Chrysophyta: Chrysophytes • Yellow-green and golden-brown algae • Gold-colored chloroplasts • Pectin cell wall • Store food in the form of oil
4) Phylum Bacillariophyta: Diatoms • Cell walls – silicon (glass) • Cannot decompose
C) Plantlike Protists: Multicellular Algae = Seaweed Red, Brown, and Green
1) Phylum Rhodophyta: Red Algae • Contain Chlorophyll a and Phycobilins • Absorb blue light – 260 meters, very deep • Important role in forming coral reefs • Chondrus crispus- Irish moss
2) Phylum Phaeophyta: Brown Algae • Chlorophyll a and c, Fucoxanthin • Holdfast, Stipe, Blades, Bladders (Fig 20-15) • Fucus- Rockweed • Sargassum • Kelp
Blade Stipe Hold Fast
3) Phylum Chlorophyta: Green Algae • Cellulose in their cell walls • Chlorophyll a & b • Stores food as starch • Very similar to plants
Unicellular Green Algae • Chlamydomonas • Lives in ponds, wet soil, etc.
Colonial Green Algae • Spirogyra • Volvox – connected strands of cytoplasm, coordinated flagella movement
Multicellular Green Algae • Sea lettuce- Ulva
Base of the food chain • Kelp forests – habitats • 50% of oxygen production • Medical Use • Ulcers, High Blood Pressure, arthritis Importance of Algae