Tritoniopsis triticea |
In addition to the binomial, which names a flowers species, each
plant has a name for each higher-level group to which it belongs. Each
plant belongs to a genus, each genus to a family, each family to an
order, each order to a class, each class to a phylum, each phylum to a
kingdom, and each kingdom to one of the three domains of life: Archaea,
Bacteria (both made up of microorganisms formed by prokaryotic, or
nucleus-free, cells), and Eukarya. The domain Eukarya, made up of
organ¬isms with cells that have nuclei, contains four king¬doms of life:
Protista (protists, mainly molds and al¬gae), Fungi (mainly
nonphotosynthetic organisms), Plantae (plants, both nonvascular and
vascular), and Animalia (animals).
Names for the higher-level flower groups, or taxa, are
all created according to rules of the ICBN. The rules for naming
higher-level groups do not indi¬cate which names are best or most
correct. Unlike the binomial genus-species names of flowers, on which
scien¬tists generally agree, the best name for the higher-level groups
to which these genera belong can sometimes be controversial. Therefore,
some of the higher-level groups have more than one proposed name of
flowers. Neither of the names is necessarily more cor¬rect than the
other. Usually the different names of flowers re¬flect different ideas
about how the higher-level groups are related to each other. In some
cases, the higher-level names that are listed were selected from several
proposed flowers names. Other sources may classify some of these genera
under slightly differ¬ent higher-level group names, as a result of the
on¬going studies, discussions, and controversies over classification.
The binomial genus-species name, however, will nearly always be the
same. The exis¬tence of more than one name for some of the higher levels
of flowers classification is simply a reminder that botanists are
constantly learning new things about plants and occasionally change
their ideas about how plants should be named.
Each of the organisms (bacteria, fungi, and plants)
listed in this appendix is alphabetized by its binomial scientific name
(far left-hand column); the most often used common name appears in the
mid¬dle column. Finally, the far-right column identifies the kingdom
(k.), phylum (p.), class (c.), order (o.), and family (f.) in which the
species is commonly classified, along with some notable characteristics.
All organisms can be assumed to belong to the do¬main Eukarya unless
one of the other domains (ei¬ther Archaea or Bacteria) is identified.
The abbrevia¬tion g., for "group," indicates a group name that is
"artificial"—that is, not based on evolutionary rela¬tionships but
rather on some common characteris-tics that have made it convenient for
researchers to regard these organisms as a group. The abbrevia-tion spp.
stands for "species" (plural).
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