Ask A Scientist© Biology Archive

Author:      ranger
Text:        Has there ever been a so-called "missing link" found that later 
was not rejected, and that could prove beyond a shadow of a doubt the theory 
of evolution?  What I mean is that over the years there have been numerous 
fossil finds, and they were supposed to be the missing link but they were all 
later rejected.  One in particular I remember was an Ora.

Response #:  1 of 2
Author:      psych
Text:        The "missing link" refers to the gaps in the knowledge base of 
the sequence of what type of being existed between homo sapiens (smart man or 
modern humans) and the presumed beast from which we evolved (be it ape, monkey 
or orangutan).  There have been a few anthropological finds that later were 
rejected as being a part of this evolutionary line but I think those are in 
the minority.  The reason there is still a missing link is because as evidence 
is unearthed further back in time then we can start looking even farther back 
in time.  Also (arguably) the gaps in the record get smaller with new finds.  
This is like much of science, there is always something that is unknown yet 
hypothetically knowable.  In the case of human evolution, the unknown is 
referred to as the "missing link."

Response #:  2 of 2
Author:      profbill
Text:        Yes there has been, many times.  Perhaps the best account of all 
this you could read would be Stephen Jay Gould's book "Wonderful Life" about 
the finds in the Burgess Shale in Canada.  At least two considerations make it 
hard to argue completely from the fossil record, though.  First, fossils are 
not a random sampling of evolution, because they favor hard-bodied, or hard 
skeleton animals.  Second, in Gould's theories, evolution may not always be 
gradual, but may proceed in many discrete leaps, so that the chance of finding 
transitional animals (missing links) may be low.  The 747 analogy is not very 
good, because natural selection directs in some sense the fate of animals.  
All the failures die without reproducing, so the improbably successes survive 
and reproduce, even though the probability of getting them in the first place 
is low.  Given enough time this works.