Biology - Chp 20 - Protists - Notes


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Biology - Chp 20 - Protists - Notes

  1. 1. Chapter 20 Protists
  2. 2. What is a Protist?• The kingdom Protista is a diverse group that may include more than 200,000 species• Biologists have argued for years over the best way to classify protists, and the issue may never be settled• In fact, protists are defined less by what they are and more by what they are notProtist - ________________________________________________________________________________________________________________________________________• Most protists are unicellular, but some are multicellularEvolution of Protists• The kingdom “Protista” means “the very first” which is appropriate because they were the first eukaryotic organism on Earth• It is hypothesized that the first Protists evolved from a symbiosis of several prokaryotic cellsEndosymbiotic theory - ____________________________________________________________________________________________________________________________________________________________________________________________________ 2
  3. 3. Classification of Protists• Protists are so diverse that biologists suggest that they should be broken up into several kingdoms• Currently biologists don’t agree how this should be done• Therefore we will look at Protists as if they belong in the same kingdom and classify them by how they obtain nutritionAnimal-like Protists• Heterotrophs - ________________________________________________________• Many are capable of locomotion o Flagella – o Cilia – o Psuedopods – o Sporozoans –  Plasmodium (malaria)Plant-like Protists• Many protists contain the green pigment chlorophyll and carry out photosynthesis• Autotrophic• However, they are not classified as plants, they are algaeEcology of Unicellular Algae• Plant-like protists play a major ecological role on earth• They make up a large part of the phytoplanktonPhytoplankton - __________________________________________________________________________________________________________________________________________________________________________________________________________• About ______ of photosynthesis on earth occurs in phytoplankton 3
  4. 4. Algal Blooms• Sometimes populations of algae grows in enormous masses called _______________• These algal blooms deplete the water of nutrients and can release toxins into the waterEx.)Fungus-like Protist• Like fungi, the fungus-like protist are heterotrophs that absorb nutrients from dead or decaying organic matter• But unlike true fungi, fungus-like protists have centrioles• They also lack the chitin cell walls of true fungiSlime molds• Slime molds are fungus-like protists that play a key role in recycling organic material• Found in places that are damp and rich in organic matterWater Molds• Fungus-like protists that thrive on dead decaying organic matter in water and some are plant parasites on landEcology of Fungus-like Protists• They are important as recyclers or organic material• They can cause diseases however o Mildews and blights o Potato famine 1845 and 1851 4
  5. 5. Name __________________________________ Date __________________ Per ______ Chapter 20 Review1. What is a protist?2. What are the three methods that protists use to obtain food?3. What is the role of unicellular algae in the environment?4. How are fungus-like protists and fungi similar? How are they different?5. What is the role of slime molds in the environment? 5