Laboratory Notes for BIO 1003
© 30 August 1999, John H. Wahlert & Mary Jean Holland
Throughout this course you will encounter the scientific names for organisms and the groups to which they belong. Each living organism has a two part or binomial name that consists of its genus and species, and the combination is unique to that organism. Both are underlined or italicized, and the genus name is capitalized, e.g. Homo sapiens or Homo sapiens. A genus can include many species, e.g. Homo erectus, Homo habilis. The same species name may be used in other genera, but the combinations of genus and species names must be unique. Once a genus name has been applied to a certain group of species, it cannot be used for any other groups of species unless they are added to its own group. The word species is both singular and plural; "specie" means currency (money). The system of binomial nomenclature was introduced by Carl Linnaeus (1707-1778) in Species plantarum (1753) and Systema naturae, 10th edition (1758), and these two works are used as the stating points for botanical and zoological nomenclature.
A classification is hierarchical with superkingdoms being the largest groups and subspecies the smallest. Each category may contain many subcategories of the next lower level. The following is a list of the categories used in this guide:Domain
Phylum or Division
A mnemonic device for remembering the first letters of each word in the sequence from Kingdom to Species is: "King Philip came 'ome from Greece Saturday."
The purpose of a classification is to organize information. Closely related organisms usually share several derived or specialized characters. For example all members of the animal phylum Cnidaria share special stinging cells called cnidoblasts on their tentacles; they have two tissue layers, and a middle mostly non-cellular layer called mesoglea; they are radially symmetrical. Simply stating that a particular kind of animal is a member of the Cnidaria tells you a lot about that animal. The most informative classifications are based on the relationships or phylogeny of the included organisms.
The following classification of organisms includes mainly the groups that will be examined in laboratory (many categories are omitted).
DOMAIN ARCHAEAKINGDOM ARCHAEAprokaryotes that share features of Bacteria and Eukarya. Discovered in harsh environments, e.g., methanogens, halophiles, and sulfur-dependent thermophiles; now known to be ubiquitous.
KINGDOM BACTERIAautotrophs (Cyanobacteria) and heterotrophs
KINGDOM PROTISTA—heterotrophs and photosynthetic autotrophs
KINGDOM FUNGI—heterotrophs, mostly saprobes, some parasites
KINGDOM PLANTAE—photosynthetic autotrophs
Return to index.