pbmnh_anthro (pbmnh_anthro) wrote,

Darwin Day Wrap-Up and the Species Problem

Hi all,

Darwin Day was yesterday, and it was hosted at Flamingo Gardens. We all agreed that we must return to the gardens, because (at least from what I saw) they are beautiful and populated by a wide range of animals. For example, I saw several (very active) otters, a pair of bobcats, and an entire flock of peacocks and peahens. There was also a tram tour through the gardens, but I only saw the tram station and nothing else. Although, I could extrapolate from everything else I saw that the tram tour would probably be quite good too.

As for the actual event, it went very well. There was an excellent turnout; I’d estimate 150 people. We literally ran out of seats. The general schedule was video/lecture/video/lecture and so on; although, we did stop for birthday cake. Of the three speakers (myself included), we covered a number of interesting subjects, including Darwin’s life and impact, Hominin fossils and Natural Selection, along with a review of the entire tree of life. We took a number of photos and video. If time permits, I will start uploading them soon.

Now, to go off on one of my tangents, I had a lengthy discussion about species/speciation with someone at the event. Indeed, I consider myself a moderate lumper (grouping animals into a smaller number of species, even if they have a few different morphological features), and my classification of the species representing Hominin evolution reflects this fact. But, as the discussion went, just what is a species? And moreover, how do you reflect evolutionary change and (eventual) speciation in your taxonomic classification? The problem originates from the fact that the Linnaean system was developed in a 2D world where an animal either was or was not a member of a particular species (length being the range of features seen in the species, and width being the chasm between these entities). That notion was one of definite, unchanged animal categories without any consideration of time. However, the evolutionary world is one of 3 dimensions, including that significant and central temporal factor (so, time is essentially depth). It is this disconnect that is problematic.

The theory of universal common descent dictates connection between all life; every species is related at some point. For example, cats and dogs share some type of mammalian-based common ancestor. So at what position as you move backwards in time should they no longer be classified as cats and dogs, and they become the common ancestor (lets say Cogs). I have never been fully satisfied with the answers that the Evolutionary Species concept gives for that question. Nonetheless, and despite my reservation, I have always defined paleo-species by the possession of a certain suite of apomorphic features. However, accounting for the issues with the Biological Species concept (for example, the ever-increasing prevalence of clearly fertile hybrids being a concern), well even this seemingly simple definition of species is thorny; thus, what can be said about something through time? I do wonder if the very concept of paleo-species needs to be re-evaluated? How do you integrate discrete (although sometimes quite fuzzy) modern-day biologically-defined species, with the entire history of the planet? Now, it is not that I do not think clear taxonomic relationships can be demonstrated, it is just when you get down to the ‘nitty-gritty.’ Is there really such a thing as a species in the past? Indeed, do species really exist at all when you look in the time dimension?

These various ramblings are not some new; the ‘species problem’ has been a fixture in biology for a number of years. Still, I sometime wonder if a novel system maybe developed to unify the Linnaean 2D world with the time component? Is that system going to be something akin to the ‘PhyloCode’? I simply do not know. Still, universal common descent is such a simple and majestic concept; it would be almost poetic to have a categorization system that matches this simplicity.
Tags: darwin day, species
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