A Diversity of Organisms

Below are listed the groups considered in this text, first (Table 1) organized  by their mechanism of energy acquisition (see chapters 18-20) and by their structure (see chapter 4-5).

As examples of the diversity of inanimate life more than 50 organism groups are described in the ‘fact sheets’ of the ‘Organism’ part of the book.  A second listing (Table 2) follows the same classification as Table 1 but with links to these organism groups. 

Finally (Table 3) there is a listing of the organism groups that is strictly alphabetical.  Note that the organism groups identified vary considerably in taxonomic level, with some species (e.g. corn, potato, wheat), some genera (e.g. pines, Chlamydomonas), some orders (e.g. rusts, coccolithophores) and some groups that do not represent a recognized taxonomic entity (e.g. molds, bracket fungi and lungwort lichen).

Each of the  ‘fact sheets’ has information relating to the coverage in the text: on phylogeny and classification, on structure, on reproduction, on matter and energy considerations and finally on the interactions of the group with physical factors and biotic factors, including humans.

In many instances a genus has been chosen to represent a larger group (e.g. Rhizopus to represent the bread molds (Zygomycota); late blight of potato, Phytopthora, to represent the water molds (Oomycota)). As discussed in chapter 2, one has to be aware that that variation is ‘hidden’ in any grouping—not all bread molds are the same and any entity selected (e.g., Rhizopus) is certainly not a ‘perfect’ representative of the group.  Also note that much of the information for any particular group may not come into focus until reading the ‘textbook’ part of the book.

TABLE 1: A classification of inanimate life

Unicellular Heterotrophic Organisms

Prokaryotes —unicellular and lacking a nucleus, aquatic and terrestrial

  • most Bacteria (but some are mixotrophic or autotrophic)
  • most Archaea (but some are mixotrophic or autotrophic)

Unicellular eukaryotes (possessing a nucleus and other organelles), aquatic and terrestrial

  • some chytrids (Chytridiomycota, a fungal group with some colonial members)
  • yeasts (these are atypical members of generally multicellular or colonial fungal groups; most are cup fungi = Ascomycota
  • cellular slime molds (these are multicellular during parts of their life)
  • some dinoflagellates (most are photosynthetic)

Unicellular and multinucleate organisms (all eukaryotes), mostly terrestrial but some aquatic

  • Plasmodial slime molds
  • Bread molds (a fungal group)
  • Glomeromycota (a fungal group, most associate with plants)
  • Water molds (not a fungal group)

Multicellular/colonial, organisms, most are terrestrial

  • Club fungi (Basidiomycota)
  • Cup fungi (Ascomycota)

Mixotrophic organisms (groups with both autotrophic and heterotrophic members, and groups with members that can shift between autotrophic and heterotrophic — all unicellular

  • Prokaryotes
    • some Bacteria
    • some Archaea
  • Eukaryotes (all are unicellular, aquatic and include members that are considered ‘algae’)
    • Euglenophytes
    • Cryptomonads
    • Dinoflagellates

Chemosynthetic organisms, all unicellular and prokaryotic

  • a few Bacteria
  • a few Archaea including methanogens

Photosynthetic organisms

  • Prokaryotes
    • some Bacteria (the Cyanobacteria and several other groups)
    • one genus of Archaea (Halobacterium)
  • Eukaryotes that are unicellular and aquatic (unicellular algae)
    • Euglenophytes
    • Cryptomonads
    • Dinoflagellates
    • Haptophytes (including cocolithophores)
    • Chlorophyta—Green algae (but many are colonial and some are multicellular)
    • Bacillariophyta — diatoms (mostly unicellular, some colonial)
    • Rhodophyta—Red algae (a few unicellular but most are colonial or multicellular)
  • Eukaryotes that are multicellular/colonial organisms and aquatic
    • Chlorophyta—Green algae (but some are unicellular)
    • Phaeophyta—Brown algae
    • Rhodophyta—Red algae (a few are unicellular)
  • Eukaryotic multicellular organisms, almost all are terrestrial
    • lacking seeds and lignin (‘non-vascular plants’)
      • Bryophyta—mosses
      • Hepatophyta—liverworts
      • Anthocerophyta—hornworts
    • lacking seeds, possessing lignin (‘vascular plants without seeds’)
      • Pterophyta—ferns
      • Lycopodiophyta—club mosses
      • Equisetophyta—horsetails
    • with seeds, without flowers (‘gymnosperms’)
      • Coniferophyta—conifers
      • Cycadophyta—cycads
      • Ginkgophyta—ginkgo
      • Gnetophyta—gnetophytes
    • with seeds and flowers
      • Anthophyta = angiospersms = flowering plants
        • monocots, including grass family and orchid family
        • ‘dicots’, including pea family and sunflower family

TABLE 2: Groups in the Organism section of the book

Unicellular Heterotrophic Organisms

Prokaryotes —unicellular and lacking a nucleus, aquatic and terrestrial

Unicellular eukaryotes (possessing a nucleus and other organelles), aquatic and terrestrial

Unicellular and multinucleate organisms (all eukaryotes), mostly terrestrial but some aquatic

Multicellular/colonial, organisms, most are terrestrial

Mixotrophic organisms (groups with both autotrophic and heterotrophic members, and groups with members that can shift between autotrophic and heterotrophic — all unicellular

  • Prokaryotes
  • Eukaryotes (all are unicellular, aquatic and include members that are considered ‘algae’)

Chemosynthetic organisms, all unicellular and prokaryotic

  • a few Bacteria Nitrobacter
  • a few Archaea including methanogens

Photosynthetic organisms

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Inanimate Life by George M. Briggs is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.