Contra common misconception - among both Creationists and evolutionists - the term "vestigial" does not mean useless and/or nonfunctional. "Vestigial" means something is a vestige of what it used to be in an evolutionary ancestor: basically, it is now a phylogenetic remnant, and due to its rudimentary state, it either performs no (known) function or it performs a function different from that of the ancestral, well-developed state.
quote:
A phylogenetic remnant that was better developed in an ancestor is vestigial. The pelvic girdle of whales is said to be vestigial because ancestors of whales were tetrapods with functional tetrapod appendages. The yolk sac of the mammalian embryo is vestigial.
(George C. Kent & Robert K. Carr, Comparative Anatomy of the Vertebrates: Ninth Edition, McGraw Hill, 2001, p26)
Note that the yolk sac of mammalian embryos does perform a function. So the above quote implicitly states that a structure can be both vestigial and functional.
Further, here is an explicit statement saying that a structure can perform a function and still be vestigial.
quote:
Opponents of evolution always raise the same argument when vestigial traits are cited as evidence for evolution. ‘The features are not useless,’ they say. ‘They are either useful for something, or we haven’t yet discovered what they’re for.’ They claim, in other words, that a trait can’t be vestigial if it still has a function or a function yet to be found.
But this rejoinder misses the point. Evolutionary theory doesn’t say that vestigial characteristics have no function. A trait can be vestigial and functional at the same time. It is vestigial not because it’s functionless, but because it no longer performs the function for which it evolved.
(Why Evolution Is True, Jerry A. Coyne, Viking, 2009, p58)
Therefore, the human coccyx is BOTH vestigial AND functional.
Edited by gragbarder, : No reason given.
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