The Definition and Description of a "Transitional"

I see the flaw in Menton's logic. He claims that simple similarities are assumed to be evidence of common ancestry. Then he goes and lists examples of similarities that are not accepted as resulting from common ancestry. Obviously it is not as simple as Menton tries to suggest.For instance dolphins icthyosaurs and sharks share a similar overall form because of the way they live. Convergent evolution is often largely the result of functional constraints - and often the results can be seen to be quite distinct. Convergent evolution is certainly not unexplained and it is clearly evidenced.Or to show the limits of convergence, the thylacine dentition lacks the distinctive carnassial tooth of the canids - the convergence does not include details like that. Convergence typically produces similarities that are seen to be "skin deep" when examined in more detail.And nowhere in the quote from Menton do we see an attempt to address the overall pattern of similarities found in living species let alone the fossil record. Yet that is a key part of the argument - but addressing it would destroy the claim that simple similarity in itself is taken as proof of common ancestry.

I notice that while you reject my comment you offer no clear refutation. Yet both my examples deal with clear examples of convergence. And if I can deal with 3 so simply who is to say that there is anything more problematic in your 110 ?You don't offer any clear examples nor do you offer any clear statement as to the scale of the problem. If convergence turns out to be a problem in closely related species then it is no threat to our ideas of large-scale evolution. It simply obscures details - and casts no doubt over the general principle of common ancestry (an analagous case might be uncertainty over whether two branches of a family split ten generations ago or eleven). Yet where are the examples that offer evidence of convergence at a scale that would cause serious problems for evolutionary theory ? I think you need to offer far more detail to actually make the case that convergence is anything like the problem you claim that it is.And it is certainly false to say that paleontologists have admitted the virtual non-existence of transitional forms. The lack is purely at the level of speciation - which you believe in. The paleontologist usually quoted by creationists on this matter is Stepehen Jay Gould - and he claimed that at higher taxonomic levels transitional fossils were abundant.

Of course similar mutations are not necessarily a problem. Remember that we are generally talking about similarities in the phenotype, and ones that have functional advantages that are difficult to obtain in other ways. Your argument manages to ignore the role of selection and as such is clearly invalid.Your example of the spiny teleosts and the Cypriniformes does not show that my state,ment is false - that is a logical error. Since my statement expressly allows for exceptions you need a large number of examples to refute it - and you do not even go into enough detail to be certain that your example is valid.And of course there is no problem with transitional fossils above species level being relatively common compared to transitionals between species. It is even a prediction of Punctuated Equilibria. Punctuated Equilibria states that species tend to last a considerable time (even in geologial terms), yet transitions between species are take place in very small populations that are geographically localised over a geologically brief period of time (mere thousands of years). So it is not surprising that we should find fossils of species representing transitions between higher taxonomic ranks while intermediates between species should be rare.Moreover we should remember that it is the transitions between higher taxonomic levels that are most problematic to creationism. Creationism can accept limited evolution between similar species. However we have transitionals representing larger scale evolutionary steps that creationists deny. Evolutionary theory states that these should exist - therefore the fact that they do is significant evidence for evolution which predicts that they would exist and creationism in which they are at best unexpected.