Casual Use
"Form taxon" can more casually be used to describe a wastebasket taxon: either a taxon that is not a natural (monophyletic) group but united by shared plesiomorphies, or a presumably artificial group of organisms whose true relationships are not known, being obscured by ecomorphological similarity. Well-known form taxa of this kind include "ducks", "fish", "reptiles" and "worms".
Read more about this topic: Form Classification
Famous quotes containing the word casual:
“Light half-believers of our casual creeds,
Who never deeply felt, nor clearly will’d,
Whose insight never has borne fruit in deeds,
Whose vague resolves never have been fulfill’d.”
—Matthew Arnold (1822–1888)
“From one casual of mine he picked this sentence. “After dinner, the men moved into the living room.” I explained to the professor that this was Ross’s way of giving the men time to push back their chairs and stand up. There must, as we know, be a comma after every move, made by men, on this earth.”
—James Thurber (1894–1961)