PROTISTS

• Ernst Haeckel


  Suggested the name Protista
• Archaea, Bacteria, Eukarya


  3 domains
• Archaea & Bacteria


  Make up all prokaryotes
• Little fossil record


  difficult to imagine what members
• Cyanobacteria


  Earliest fossil: domain bacteria in 3.5 - 3.8
• Stromatolites


  Suggest prokaryotes lived in interactive communities
• 2.1 BYA


  Living eukaryotes have cells measuring 10 μm or greater
• Mitosis


  Cell division in eukaryotes
• Histones


  Proteins that organize chromosomes in eukaryotes
• Mitochondria


  Organelles for energy production in eukaryotic cells
• Flagella and cilia


  Structures for cell movement in eukaryotes
• Chromosomes


  Organized by histones in eukaryotes
• Sexual Reproduction


  Reproduction involving genetic recombination
• Cell walls


  Outer layer providing structure in eukaryotes
• Characteristics in all major groups of eukaryotes

  1. Cells with nuclei surrounded by a nuclear envelope with nuclear pores

  2. Mitochondria

  3. Cytoskeleton of microtubules and microfilaments

  4. Flagella and cilia

  5. Chromosomes organized by histones

  6. Mitosis

  7. Sexual Reproduction

  8.Cell walls
• Endosymbiotic Theory


  Originated from ancestral prokaryote with endosymbiotic relationships
• Protists


  Eukaryotes not classified as animals, plants, or fungi
• Commensals/parasites


  Protists living in symbiotic relationships
• Mixotrophs


  Protists obtaining nutrition via multiple routes (heterotrophic or photoautotrophic)
• Phagocytosis


  Ingestion of particles by cell engulfment
• Phagolysosome


  Vesicle formed by fusion of phagosome and lysosome
• process of metabolism of eukaryotes

  phagosome > fuse w/ lysosome (hydraulic enzyme), produces phagolysosome > food broken down > waste disposition (exocytosis)
• Exocytosis


  waste are expelled from the cell through this process
• Saprobes


  absorb nutrients from dead organisms or their organic wastes
• 1/ more flagella


  How many moving organs does eukaryotes have?
• Taxis


  Movement toward or away from a stimulus
• Binary fission


  Asexual reproduction by cell division
• True slime molds


  example of a protists that exhibit multiple fission and simultaneously divide into many daughter cells
• Alternation of generations


  Life cycle strategy with haploid and diploid stages
• Animals


  unicellular in the haploid form and multicellular in the diploid form
• Plants


  multicellular stages in both haploid and diploid forms, a strategy called alternation of generations
• freshwater and marine environments, damp soil, and even snow


  habitat of protists
• Zooplankton


  Organisms consuming protists directly
• Photosynthetic protists


  serve as producers of nutrition for other organisms
• Zooxanthellae are ________.


  symbiotic algae that provide corals with energy via their photosynthetic activity
• Mixotrophic


  Paramecium & other species of ciliates (due to symbiotic relationship with green algae)
• Pathogen


  Organism causing disease
• Parasitic Organisms


  live in/on a host organism & harm it
• Fungus-like protist saprobes


  specialized to absorb nutrients from nonliving organic matter (dead organisms/wastes)
• Saprobic protists


  have the essential function of returning inorganic nutrients to the soil and water