New Species Creation?

There are quite a few examples of organisms we consider "species" that are actually symbionts. Lichens, portuguese man-of-war, etc. Dr. Margulis, unfortunately, has gone way outboard by proclaiming that symbiosis is the primary means of speciation. I don't think that contention is even remotely supported. Development of genetic incompatibility through geographic or behavioral isolation remains the key ingredient in speciation. (See for example, Orr 1995, "The Population Genetics of Speciation: The Evolution of Hybrid Incompatibilities", Genetics 139:1805-1813).Where I think Margulis might have a better case is in early metazoan evolution - how did those first cells or multi-cellular critters evolve? In this case, symbiosis and serial endosymbiosis seems to be a pretty likely scenario.And yeah, assuming termites are like ants in that respect, each species should have different gut bacterial symbionts that evolved along with their hosts.

I don't disagree WK. About the only useful distinction you can make with unicellular organisms is clonal lineage. Mayr (or somebody) coined the term "agamaspecies" to describe what happens when bacterial lineages (for example) diverge through conjugation/mutation/etc and the intermediate lineages die out or disappear. It's an even squishier concept than species - and we all know how indeterminate that is. After all, unlike the pre- or post-zygotic barriers in sexually reproducing organisms or the instant speciation by polyploidy, there's literally no barrier to preventing these agamaspecies from re-homogenizing down the road. Still, I think conceptually for the purposes of this particular discussion, the idea can be used.Anyway, I was talking about serial endosymbiosis creating instant new single cell organisms and hence new clonal lineages and hence new "species". Isn't that basically the scenario for the encorporation of mitochondria and chloroplasts, and possibly other organelles, in the first eukaryotes? It's not that great a stretch of imagination to get from there to colony organisms to colonial organisms with specialization like the man-of-war.Anyway, this is way beyond my expertise. Someone might want to chime in here.