Copyright Pearson Prentice Hall Biology Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Before starting Protists, a video on Cordyceps: attack of the killer fungi (3min): https://www.youtube.com/watch?v=XuKjBIBBAL8 Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 The Kingdom Protista Photo Credit: Andrew Syred/Science Photo Library/Photo Researchers, Inc. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Protists are eukaryotes that are not members of the Plant, Animal, or Fungi kingdoms. In Greek, Protista means “the very first” : Protists are the first eukaryotic organisms on Earth What Is a Protist? What Is a Protist? Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Evolution of Protists Origin of the first eukaryotic cell: Mitochondria (first engulfing) and chloroplasts (2nd engulfing) in eukaryotic cells may have descended from prokaryotes that lived inside larger cells (Endosymbiosis). 2 1 Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall What Is a Protist? The kingdom Protista may include more than 200,000 species. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Most, but not all, protists are unicellular. Solitary Colonial Multicellular Single cell life Usually unicellulars Differentiated cells with living as a group specific functions Ex. Chlamydomonas Ex. Volvox Ex. Ulva Copyright Pearson Prentice Hall
Classification of Protists One way protists can be classified is by how they obtain nutrition (3 groups): Heterotrophs are called animal-like protists. Photosynthesizers are called plantlike protists. Decomposers and parasites (external digestion) are called funguslike protists. This classification does not reflect the evolutionary history of these organisms ! Copyright Pearson Prentice Hall
Classification of Protists Protists are difficult to classify because they often have characteristics in common with more than one of the three groups Ex.: Euglena photosynthetic (plant-like) + flagella (animal-like) Powerful tools of molecular biology illuminate more and more the true evolutionary phylogeny of protists. At present, biologists don’t agree on how to classify the protists. Therefore, we will take the traditional approach. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Video Protist Rap song (2m30s): https://www.youtube.com/watch?v=CibGFo0RHIw Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 A protist is any organism that is not a plant, an animal, a fungus, or a prokaryote. True False Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 Funguslike protists are autotrophic. photosynthetic. parasitic. chemosynthetic. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 Animal-like protists are autotrophs. heterotrophs. decomposers. producers. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 Biologists have difficulties classifying protists because their DNA cannot be examined. evidence suggests that they evolved from so many different groups. structural similarities used for classification are difficult to detect. their ancestors may have evolved through symbiosis. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall 20-1 An organism is classified as a protist if it resembles any other member of the Eukarya domain. shares DNA sequences that are found only in other protists. has a cell wall made of cellulose. does not belong in any other kingdom of the Eukarya. Copyright Pearson Prentice Hall
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