Irreduceable Complexity

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Originally posted by Mozambu:
But there is no empirical evidence that speciation is the accumulation of microevolutionary change through time.

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There is actually quite alot of good epirical evidence that evolutionary adaption to a specific environment results in reproductive isolation between two populations of the same species. This process is called ecological speciation and is probably one of the commonest forms of speciation.see:"The ecological hypothesis of speciation is that reproductive isolation evolves ultimately as a consequence of divergent natural selection on traits between environments.""I review the mechanisms that give rise to new species by divergent selection"Dolph Schluter. Ecology and the origin of species. TRENDS in Ecology & Evolution Vol.16 No.7 July 2001."new findings that characters affecting reproductive isolation can diverge rapidly in sympatry as a result of natural selection. Recent studies combining research on phylogeny and ecology of natural populations cast new light on patterns, timescales and mechanisms, and emphasize the role of ecological factors in speciation. Studies of parallel speciation provide a strong case for sympatric speciation and for natural selection generating reproductive barriers."Kerstin Johannesson. Parallel speciation: a key to sympatric divergence. TRENDS in Ecology & Evolution Vol.16 No.3 March 2001.Jim mallet has done alot of work on speciation and several of his papers can be downloaded here: Jim Mallet home pagefor example: IGOR EMELIANOV, MICHELE DRES, WERNER BALTENSWEILER, AND JAMES MALLET. HOST-INDUCED ASSORTATIVE MATING IN HOST RACES OF THE LARCH BUDMOTH. Evolution, 55(10), 2001, pp. 2002—2010.

I understand microevolutionary change to be small changes for example the timing of events such as flowering in plants or emergence in insects. For example in monkey flowers the gene that allows one population of the plant to survive on copper contaminated soils directly prevents reproduction with other monkey flowers that do not live on copper contaminated flowers. Natural selection for copper tolerance led directly to reproductive isolation.I agree the study of speciation has been a bit of a mess but this is beginning to change, this article is a good intoduction to the recent changes in the study and unserstanding of speciation: http://abacus.gene.ucl.ac.uk/jim/pap/malletjeb01.pdfThere is alot of research that has gathered good epirical evidence and it is listed in the reviews i mentioned, here are some more primary refernces if people are interested:A. P. Hendry. Adaptive divergence and the evolution of reproductive isolation in the wild: an empirical demonstration using introduced sockeye salmon. Genetica 112—113: 515—534, 2001.Schemske, D.W. and Bradshaw, H.D., Jr (1999) Pollinator preference and the evolution of floral traits in monkey flowers (Mimulus). Proc. Natl. Acad. Sci. U. S. A. 96, 11910—11915 Nagel, L. and Schluter, D. (1998).Nagel, L. and Schluter, D. (1998) Body size, natural selection, and speciation in sticklebacks. Evolution 52, 209—218.Via, S. et al. (2000) Reproductive isolation between divergent races of pea aphids on two hosts: selection against migrants and hybrids in
the parental environments. Evolution 54, 1626—1637.