19.2 - The Three-Domain System (Biology / Sylvia S. Mader, Michael Windelspecht, ASU -- Twelfth Edition)

  1. until 1969, there were only 3 kingdoms, which was then expanded to 5

  2. Defining the Domains:

    1. in the late 1970’s Carl Woese designated prokaryotes into domains Bacteria and Archaea, and eukaryotes into Eukarya

      1. this was the invention of the domain system

  3. Domain Bacteria:

    1. diverse, found in large numbers in every environment

    2. biochemically (not structurally) different from Archaea

    3. variety of nutrient systems

  4. Domain Archaea:

    1. prokaryotic, single-celled, asexually reproducing

    2. cell wall, rRNA & biochemistry differ from bacteria

    3. known for surviving in extremity

  5. Domain Eukarya:

    1. can be single/multi-cellular

    2. are eukaryotic = have membrane bound nucleus

    3. have organelles

      1. Protists:

        1. diverse group of single-celled organisms

        2. no “true tissues”

        3. some heterotrophic (ingestion/absorption), some photosynthetic

      2. Fungi:

        1. eukaryotes w/spores, no flagella

        2. typically multicellular

        3. saprotrophic = absorb nutrients from decaying matter

      3. Plants:

        1. photosynthetic, multicellular

        2. primarily adapted to land

        3. have true tissues

        4. have organ system organization level

      4. Animals:

        1. motile, eukaryotic, multicellular, heterotrophic

        2. have true tissues

        3. have organ system organization level