kuento@kuhub.cc.ukans.edu (11/02/90)
In article <4578@husc6.harvard.edu>, Ellington@Frodo.MGH.Harvard.EDU (Deaddog) writes: > I may be misreading your intent, but it seems as though you want to > classify archaebacteria as 'living fossils'--and there just ain't such a > thing. > A.E. > > Dept. Mol. Biol. > Mass. General Hospital > Non-woof This may have just been a throw-away line at the end of the message, but I feel the attitude about "living fossils" points out one of those debatable points in biology, and one I'd like to comment on. First, I agree that the term "living fossil" is tossed around a bit too liberally, and applied to organisms without thought to being able to prove what the term implies. There are, for example, plenty of fossil Coelacanths, and only one known living species - this, by way of the vernacular, makes it a good example of a "living fossil" - but this does NOT mean that the modern species has itself persisted all those millions of years. I presume it is this point that Dr.(?) Ellington was trying to emphasize - simply because an organism is a member of an old lineage, and has similar fossilized relatives, does not mean that organism is itself an old species. Fossils also tell us relatively little about behavior and biology, so we can never really be sure, for example, that a modern Coelacanth is a good representative of its ancestors in any way besides morphology. Yes, we may never really be able to *prove* that an organism is a living fossil in the truest sense. This doesn't mean they don't exist. There is at least one dramatic case that *almost* identified a true living fossil: the oldest fossil bee. It was found in 80-million- year-old amber, and recognizable as a close relative (as in *very* close) of a modern Stingless bee in the genus _Trigona_. The fossil bee would NOT appear as the most "primitive" member of the genus, (if one were to incorporate it into a phylogenetic analysis of Trigona) either. So, if it had turned out that this same species *did* still exist, would this not have been a true living fossil? We just need to be luckier with our paleontological finds, and sooner or later, we'll have the definitive reply to Dr. Ellington's remark. 8-) (Just incidentally, how old would something have to be before we could justify the "fossil" apellation? Opinions? Other definitions of the term in general?) ---------------------------------------------------------------- Doug Yanega (Snow Museum, Univ. of KS, Lawrence, KS 66045) My card: 0 The Fool Bitnet: Beeman@ukanvm "This is my theory, such as it is....which is mine. AAH-HEM!"