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Message: <blockquote data-quote="l_raty" data-source="post: 1147815" data-attributes="member: 24811">Surely interesting, but knowing it happened is not going to solve the problems associated to sympatric speciation (and the taxonomy of crossbills <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" /> ). These problems lie, partly at least, at a completely different level. A.o.:- Sympatric speciation is logically incompatible with the taxonomic system.Taxonomy works with a system of increasingly inclusive grouping levels, in which populations are by definition less inclusive than species. In a sympatric speciation process, a population (less inclusive) splits into two species (more inclusive). This simply cannot work.- Sympatric speciation is logically incompatible with the Biological Species Concept.In a classic allopatric speciation process, the progressive accumulation of differences in two allopatric populations finally results in two reproductively isolated species. A sympatric speciation process is the exact opposite: a population evolves into two distinct morphotypes, typically in answer to disruptive selection (selection against the "average" phenotype); these morphotypes must cease to interbreed - this is a sine qua non condition: if not, they will never evolve into more distinct entities; at this stage, in models at least, these morphotypes do not need to show any sort of genetic divergence other than quantitative; at this stage, reproductive isolation will typically still be under the control of extrinsic (environmental) factors - change these factors, the barriers could break down very easily. From this point on, the morphotypes will start following divergent evolutionary paths, and accumulate qualitative differences. Effective reproductive isolation is the final outcome of an allopatric speciation process, but it is only the starting point of a sympatric speciation process. The BSC assumes "speciation = reproductive isolation". This concept is intrinsically rooted in the assumption that speciation must be allopatric, and becomes completely flawed if applied to sympatric speciation.(In fact, I've long been wondering to which extent the "classic" rejection of the sympatric speciation hypothesis had not always been a consequence of it being hardly compatible with widely accepted taxonomic concepts...)</blockquote>

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