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 member