Descent with Modification v. Larval Hybridization

(a) is closest to the observed pattern. (b) does not match the evidence where the fossil record is detailed enough to distinguish it from (a), and is indistinguishable from (a) across most of the evidence. As for (c), well, it commits both the error of (b) and compounds it with suggesting an unobserved mechanism for additional change - it could be possible; but until you can show me some compelling evidence? I remain sceptical.(a) then is the more convincing, although it shows a more consistent rate of change than that supported by the data.

It might be possible; but I'd need evidence of it occuring before I accept it as an explaination; frankly, the letters link you posted in your first post covers the reasons I don't give credence to the idea. There is no "punc eq"; it doesn't need explaining.

Actually, that brings up an interesting point - if this genetic transfer is occuring why aren't we seeing evidence of it on cladistic trees reconstructed from genetic data?

It depends what you mean by that; there is horizontal gene transfer between organisms, and certain apparently deeply significant events in evolutionary history appear to have occurred by advanced symbiosis - most obviously the history of mitochondria and other organelles in Eukaryotic cells.But the extent to which these events have influenced evolution is not clear, particularly among the "higher" organisms. Also, it is not clear to me that these are not considered most productively as special forms of individual heritable variation (of which mutation and sexual recombination form the two most important examples) upon which the normal processes of natural selection then operate rather than as distinct processes of evolution.Finally, various non-adaptive effects certainly do occur (genetic drift and the founder effect to name just two) but, again, these are processes that operate with, rather than instead of, descent with modification.Even if larval hybridization does turn out to be correct; it will represent a new means of generating genetic variety rather than a strictly alternative means of evolving.