hamilcarr: You may want to consider this article on observed instances of speciation.
Excerpted from your source:
2.0 Species Definitions
A discussion of speciation requires a definition of what constitutes a species. This is a topic of considerable debate within the biological community. Three recent reviews in the Journal of Phycology give some idea of the scope of the debate (Castenholz 1992, Manhart and McCourt 1992, Wood and Leatham 1992). There are a variety of different species concept currently in use by biologists. These include folk, biological, morphological, genetic, paleontological, evolutionary, phylogenetic and biosystematic definitions. In the interest of brevity, I'll only discuss four of these -- folk, biological, morphological and phylogenetic. A good review of species definitions is given in Stuessy 1990.
2.1 The Folk Concept of Species
Naturalists around the world have found that the individual plants and animals they see can be mentally grouped into a number of taxa, in which the individuals are basically alike. In societies that are close to nature, each taxon is given a name. These sorts of folk taxonomies have two features in common. One aspect is the idea of reproductive compatability and continuity within a species. Dogs beget dogs, they never beget cats! This has a firm grounding in folk knowledge. The second notion is that there is a discontinuity of variation between species. In other words, you can tell species apart by looking at them (Cronquist 1988).
2.2 The Biological Species Concept
Over the last few decades the theoretically preeminent species definition has been the biological species concept (BSC). This concept defines a species as a reproductive community.
Between these two, I recommend neither.
The author of your source uses BSC, which, conveniently for your intents on this thread, allow for non-reproductive "species" (in which concept, mules are a species rather than a hybrid of two genetically similar species) and for "species" for which there is and has ever been only ONE known example to have ever existed.
I would obviously be receptive to an example of speciation via the Folk Species Concept, but I think that an unreasonably severe standard to meet and one I am sure you will readily agree you could not produce an example of.
The Phenetic Species Concept would not be an unreasonably severe standard to meet if speciation is observably occurring to that degree.
On the whole, I wonder if you even read the piece you linked. It throroughly confirms what I stated regarding self-limiting boundaries on viability. Without viability there may as well be no speciation recognized even using the BSC, because it could not propogate and therefore could not maintain existence as a species. A remarkable observation in your link is that without BOUNDARIES to prevent interbreeding sterilization results to speciated samples. How such naturally occurring boundaries be possible in sufficient quantity to account for what we all see around us every day, when it comes to variation of species?