For other uses, see
phyla. In
biological taxonomy, a phylum (
Greek plural: phyla) is a
taxon in the rank below
kingdom and above
class. "Phylum" is adopted from the Greek phylai, the clan-based voting groups in Greek city-states. Phyla represent the largest generally accepted groupings of
animals and other living things with certain
evolutionary traits, although the phyla themselves may sometimes be grouped into superphyla (e.g.
Ecdysozoa with eight phyla, including
arthropods and
roundworms; and
Deuterostomia with the
echinoderms,
chordates,
hemichordates and
arrow worms). Informally, phyla can be thought of as grouping animals based on general body plan; this is
morphological grouping. Thus despite the seemingly different external appearances of organisms, they are classified into phyla based on their internal organizations. For example, though seemingly divergent,
spiders and
crabs both belong to
Arthropoda, whereas
earthworms and
tapeworms, similar in shape, are from
Annelida and
Platyhelminthes, respectively. Although the
International Code of Botanical Nomenclature allows the use of the term "Phylum" in reference to
plants, the term "
Division" is almost always used by botanists.
See more at Wikipedia.org...
Free Download Now!
