From Whence They Came...

One thing I've always been interested in is how variable individuals within a given species are. Just look at the diversity among human beings, for instance. Even more amazing is the crazy variation among domesticated animals, like dogs.

Plants are no different, and we frequently cultivate variants that have some unique trait or the other. For many of our food crops, these traits relate to disease resistance, or to stress tolerance, or to some sort of yield parameter. For example, cabbage, broccoli, kale, brussels sprouts, and cauliflower are all different forms of the exact same species: Brassica oleracea. Among ornamentals, the foci are more commonly aesthetic: big monstrous flowers, dazzling red fruits, frilly leaf shapes, curly-q branches, etc... Those are all fun things to look into from a research perspective, but I have been more fascinated with how individuals within a species differ as a function of their geographic origin. While these differences may be morphological (like bigger flowers), more often than not it is some physiologic difference that is peculiar. The older term in the literature for this discipline of study is genecology, and while the word is infrequently encountered these days, I still like to use it.

The first species that prompted me to think about such matters was the cedar of Lebanon, Cedrus libani. My advisor from Purdue University lauded the species' attributes, and in particular a unique provenance mentioned below. This fabled evergreen of yore hails from the Mediterranean and was the apparent source of timber for the Temple of Solomon. Unlike other members of the genus, this species gets flat-topped in dotage, and has strong, horizontal branches. While it could be cultivated throughout much of Europe, growing it in colder climates of North America proved to be a challenge, indeed. After countless failed attempts to find a source that was able to survive the winters of Boston, MA, C. S. Sargent (the first director of the Arnold Arboretum) eventually obtained seed collected from the Taurus Mountains of Turkey. Because of the high altitude in which they grew, these populations were pre-adapted to the cold winters of temperate North America -- including Boston. Recognizing that this provenance was unique (and reliably cold hardy), botanists placed plants of this origin into their own subspecies: Cedrus libani ssp. stenocoma. The image above is of one such specimen growing at the Morris Arboretum of the University of Pennsylvania; its origins can be traced through Sargent's earlier efforts.

This gets me ruminating... So, what about people? Ever think about your provenance and its effects on you? I'm not talking about morphology or physiology, but more the person each of us is today and the individual BAVs (beliefs, attitudes, and values) that we possess. How much of this is due to our place of origin? And, to what degree are we able to change? While I am certainly in a different locale from where I was raised, I'm not so certain I am that different from the person I was at age 18. And yet, when I'm put back in the middle of smalltown Indiana, particularly when talking to former classmates from high school, I feel like a total alien. Surely, I have changed, but how much? In trying to explain it, the ecologist in me ponders the potential for plasticity. Maybe some origins have a strangle-hold over those who grew up there, essentially producing 'specialists' unable to acclimate to a new environment, whereas other origins produce 'jacks of all trades' able to fit in any place. Or maybe all origins are the same and there is the same subset in each population, say 10%, that is able to respond (favorably) to a new environment. Had my fellow classmates even bothered to have a 10-year reunion a few years ago, I would have been able to assess such plasticity better -- there were a few that moved away like me. But, because most of them are deadbeats, the reunion wasn't even organized. Maybe I'll be able to conduct the experiment in another 10 years if they have a 20- or 25-year reunion. Alternatively, JB and his wife are coming up on their respective 10-year reunions. Maybe I can convince them to study this for me.