A Sampling of Inanimate Life

The following ‘Organisms’ section of the book considers more than 50 groups of organisms as examples of the diversity of inanimate life.  How might these fifty-plus groups be organized?  The simplest method  is an alphabetical list; this is done in the Table of Contents of the book and is also present as a list at the end of this section.  Another, and a more ‘biological’, way to organize (i.e. classify) these groups would be in a taxonomic scheme, utilizing four of  the five kingdoms sometimes used to group organisms: Monerans, Protists, Fungi and Plants.  But, as discussed in the introduction, the five-kingdom classification has largely been replaced with more phylogenetic approaches.  Unfortunately, such classifications are still in flux and are also unwieldy, as a visit to most general biology textbooks will attest.

Instead, and since this book emphasizes the structure and nutrition of different groups, the following classification of organisms is presented based on

  • their mode of energy acquisition
    • heterotroph, autotroph (photosynthetic and chemosynthetic)
  • their structural features
    • prokaryote vs. eukaryote,
    • composition (cellular nature, see chapter 3)
      • unicellular, multinucleate, colonial or multicellular

Table 1 presents such a classification and Table 2 repeats it with links to the groups covered. Note that the groups identified vary considerably in taxonomic level, with some at the level of species (e.g. corn, potato), some at the level of genera (e.g. pines, Chlamydomonas), some at the level of orders (e.g. rusts, coccolithophores) and some groups that do not represent a recognized taxonomic entity (e.g. molds, bracket fungi and lungwort lichen).

For each group there is information relating to the coverage in the text, outlining the group’s:

  • phylogeny and classification,
  • structure,
  • reproduction
  • matter and energy considerations
  • interactions  with physical 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 variation is ‘hidden’ in any name (i.e. grouping)—not all bread molds are the same, and any entity that might be selected to represent a group is certainly not a ‘perfect’ representative of the group.  Also note that much of the information for any of these groups may not come into focus until reading the ‘textbook’ part of the book (chapters 1-31).

TABLE 1: A classification of inanimate life

Heterotrophs

Prokaryotes (lacking a nucleus and cellular organelles

  • unicellular
    • most Bacteria
    • most Archaea
  • filamentous (colonial)
    • some Bacteria
    • some Archaea

Eukaryotes (possessing a nucleus and other organelles)

  • Unicellular with a single nucleus
    • 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 (but most are photosynthetic)
  • Unicellular and multinucleate organisms
    • Plasmodial slime molds
    • Bread molds (a fungal group)
    • Glomeromycota (a fungal group, most associate with plants)
    • ‘Water molds’ (not a fungal group)
  • colonial organisms
    • Club fungi (Basidiomycota)
    • Cup fungi (Ascomycota)
  • multicellular organisms
    • Club fungi (Basidiomycota)
    • Cup fungi (Ascomycota)
    • (gametophytes of club mosses)
    • (a few seed plants)

Autotrophs

Chemosynthetic autotrophs (all are prokaryotic)

  • a few Bacteria (e.g. nitrifying bacteria)
  • a few Archaea, including some methanogens

Photosynthetic organisms

  • Prokaryotes
    • some Bacteria (the Cyanobacteria and also several other groups)
  • Eukaryotes that are unicellular
    • Euglenophytes
    • Crypto-monads
    • Dinoflagellates
    • Haptophytes (including cocolithophores)
    • Chlorophyta—Green algae (but many are multinucleate, 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 unicellular and multinucleate
    • some Chlorophyta—Green algae
  • Eukaryotes that are colonial
    • some diatoms
    • some Chlorophyta—Green algae
    • some Phaeophyta—Brown algae
    • some Rhodophyta—Red algae (a few are unicellular)
  • Eukaryotes that are multicellular organisms
    • aquatic
      • some Chlorophyta (Green algae)
      • some Phaeophyta (Brown algae)
      • some Rhodophyta (Red algae)
    • 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 = angiosperms = flowering plants
          • monocots, including grass family and orchid family
          • ‘dicots’, including pea family and sunflower family

Autotrophs that need organic carbon

(groups with both autotrophic and heterotrophic members), and groups with members that can shift between autotrophic and heterotrophic; all are unicellular.

  • Prokaryotes
    • some Bacteria  (some of the nitrifying bacteria)
    • one genus of Archaea (Halobacterium)

Mixotrophic organisms

(groups with both autotrophic and heterotrophic members), and groups with members that can shift between autotrophic and heterotrophic; all are unicellular.

  • Prokaryotes
    • some Bacteria
    • some Archaea
  • Eukaryotes (all are in groups considered ‘algae ‘)
    • Euglenophytes
    • Cryptomonads
    • Dinoflagellates

TABLE  2: Groups covered in the organism section of the book 

Heterotrophs

Prokaryotes (lacking a nucleus and cellular organelles

Eukaryotes (possessing a nucleus and other organelles)

Autotrophs

Chemosynthetic organisms (all are prokaryotic)

Photosynthetic organisms

Autotrophs that need organic carbon

(groups with both autotrophic and heterotrophic members), and groups with members that can shift between autotrophic and heterotrophic; all are unicellular.

Mixotrophic organisms

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

Alphabetic listing of groups 

Acetabularia, an unusual unicellular green algae

Agaricus bisporus, the commercial mushroom

Alfalfa

Bracket Fungi

Calupera, a large coenocytic green algae.

Chara, the stoneworts

Chlamydomonas, a small unicellular green alga

Chytrids, tiny fungi

Clubmosses: Lycopodium

Coccolithophores, photosynthetic unicellular algae

Coltsoot: Tussilago farfara

Corn

Corralorhiza, a plant that eats fungi

Cryptomonads, unicellular photosynthetic algae

Dandelion

Diatoms, unicellular photosynthetic algae

Dictyostelium: a cellular slime mold

Ephedra: jointfir

Euglena: a unicellular algae

Ginkgo

Glomeromycota: important mycorrhizal fungi

Gonyaulax: a dinoflagellate

Halobacterium

Hemlock

Horsetails, the genus Equisetum

Juniper

Kelp: Laminaria, a brown algae

Lungwort lichen (Lobaria pumonaria)

Marchantia: thalloid liverwort

Marsilea: the 4-leaf clover fern

Methanogens

Molds: ubiquitous fungi

Nitrifying bacteria

Nostoc: the smallest multicellular organism

Oedogonium: a filamentous green algae

Physarum: a plasmodial slime mold

Phytophthora

Pinus: pine trees

Polytrichium: hairy cap moss

Populus

Potatoes: Solanum tuberosum

Porphyra: an edible red algae

Redwoods: the tallest and largest trees

Rhizobium: nitrogen fixing bacteria

Rhizopus

Rice

Rust fungi (order Pucciniales, formerly Uredinales)

Sagebrush

Sarracenia, a carnivorous plant

Seaweed, Fucus: a brown algae

Sensitive fern

Soybeans (and other beans)

Sphagnum-peat moss

Sunflower: Helianthus annuus

Tar Spot Fungus

Thermus aquaticus

Wheat

Wood ferns

Yeast

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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.