Hello Jeff,
Yes you are correct that maybe I needed to be more clear…….. I was certainly not seeing it as changing the status of species as they evolve. That process is too slow and not within our time scale. I see David’s suggestion as changing the nomenclature of a range of forms as our understanding of these forms improves. But this is not an easy or cheap process and subject to ongoing change and differences of opinion. Maybe our conservation and research dollar is better spent on recognising the diversity and trying to preserve it, rather than worrying too much about whether we call them species, subspecies or whatever (for the purpose of tick lists).
I was referring to the biology of the forms as they are now, more than what we call them and where we draw the lines. Evolution has everything to do with this, as it is the process that drives the speciation. Some species are now at the point of diverging but have not completed the process yet (such as eastern and western forms of various species that have become variously isolated by a drying continent as Australia moves northwards). However we do not and can not be precise about where on the evolutionary pathway every such species is, at this point in evolutionary time. As the process is happening now, differentiation noted now in some of these difficult cases of very similar forms is probably midway through a time span of many millennia or millions of years. Some taxa will not neatly fit on one side or another of whatever constitutes speciation.
Thus some of these close ones will be arbitrary in our taxonomic opinions.
Philip
