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PROTISTS
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Characteristics Most are unicellular Some form colonies
(multicellular)
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Cells are eukaryotic Draw the following diagram
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Reproduce “mainly” by binary fission
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Like moist surroundings
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The protist kingdom is very diverse and consists of 3 main groups:
Plant-like protists Animal-like protists Fungi-like protists
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Plant – Like Protists Contain chlorophyll Can photosynthesize
Take in CO2 and give off O2 Are also able to engulf solid food
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Plant-Like Protists Example: Euglena Has eye spot Has flagellum
used to locate nutrients Has flagellum
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Plant-Like Protists Example: Algae Red, green and brown algae
Contain chlorophyll Red and brown algae are called seaweed Supplies 80% of the world’s oxygen
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Algae Reproduction Can reproduce 3 different ways
Fragmentation – asexual, the organism simply breaks apart Binary Fission – asexual Conjugation – sexual There are many variations in reproduction, depending upon the organism itself
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Algae: How do we use it? Fertilizer In gels Cosmetics Ice cream Paint
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Animal-Like Protists a.k.a. Protozoans Unicellular
Heterotrophs (rely on other organisms for food) Must move to obtain food Engulfs food or absorbs directly through their cell membranes Reproduce by binary fission
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Protozoans are classified according to their type of locomotion
Ciliophora – use cilia (tiny hairs) Sarcodina – use pseudopods Mastigophora – use flagella Sporozoa – parasitic, depend on host fluids for movement
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Ciliophora a.k.a. Ciliates Live in both fresh and salt water
Example: Paramecium Food enters the mouth pore and exits from the anal pore
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Sarcodina Example: Amoeba Moves by extending and retracting its
pseudopods Cytoplasm has 2 layers: ectoplasm and endoplasm The fluid movement of endoplasm causes the amoeba to constantly change shape
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Sarcodina Feeds by phagocytosis Food gets enclosed in food vacuole
Pseudopods flow around the food Engulfs Food gets enclosed in food vacuole Water comes in by phagocytosis or by diffusion through the membrane
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Mastigophora Ex: Chilomonas Flagella is made of protein microtubules
One of the chief sources of food for the amoeba
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Sporozoa Example: Plasmodium vivax Malaria parasite
Transferred by mosquitoes and humans Can be treated with drugs Multiply asexually in animals by forming spores and can develop into other sporozoa without fertilization
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Example: Giardia lamblia
a.k.a Beaver fever Causes stomach upset and diarrhea Flagellated sporozoa
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Fungi-Like Protists Slime moulds
Prefer cool, shady, moist environments Become amoeba-like or grow flagella OR can produce spores Start as unicellular, but eventually combine with others and become multicellular Useful as decomposers
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Protists are VERY important
Protists provide marine animals with food and supply the oceans and land with oxygen Phytoplankton (autotrophic-do photosynthesis) are at the bottom of the marine food chain Zooplankton (hetertrophic- don’t do photosynthesis) eat phytoplankton. Both are food to filter-feeding whales
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Some protists Trichomonas hominis live in humans’ intestines, feeds on undigested materials, harmless Other protists live in termites’ digestive tract and digest the wood they eat. They couldn’t do this without them!
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