Teresa, I remember hearing, many years ago, of a teacher who offered to give any student a "A" in the course who could ask one intelligent question. She didn't say how she defined "intelligent question," and I've always wondered if that wasn't the question.
I look forward to, not merely your compilation, but to your making sense of all the responses. I hope you will discuss the various definitions, areas of broad agreement, and identify areas still in dispute. And, I hope you will reach a reasoned conclusion about the degree of urgency and the nature of the problem. I suppose I'd may as well throw in my sense of the matter, however simple-minded. I'm not sure I have any "answer." But I plan to stay on the quest as long as I can keep whole armies of organisms from making a meal out of me. 1. "Colonizing" is what organisms do. That is, they do what they can to survive and reproduce. 2. Populations of organisms go up and down in response to changes, genetic and environmental, according to their requirements for life and reproduction. 3. Organisms that are broadly adapted, survive broadly. 4. The history of the earth as best we can understand it through the paleontological record, consists of many species that evolved, adapted, and survived to the present day--or could not or did not adapt sufficiently to changes, some catastrophic, some gradual. 5. Interactions between and among species are part of a Great Jiggling and Juggling, from microbes to, uh, humankind and beyond. Those interactions interact with other interactions, ad infinitum (I hope). 6. When a more or less dynamically stable (nothing is static) habitat is "disturbed" or "perturbed," the "system" reacts. (Of course, "perturbation" is change, eh?) Adapted organisms rush in to the site of perturbation--they are "opportunistic." 7. "Weeds" (colonizing species) that appear to rush in to the perturbation site can be "native" or "alien" to the immediate region, but they must be adapted to the conditions consequent to the disturbance. The scale can be small or large. As conditions change (as a result of the weeds' action or other changes), other "colonists," native or alien, sooner or later (sometimes much, much later, perhaps beyond the human time-scale--or certainly one summer) also come to occupy the site, first with the weeds, then perhaps effecting such change on the site that conditions are no longer suited to the weeds and it comes to resemble, to US at least, the way it was before the disturbance, and what we see as "dynamic equilibrium" "returns." If "we" help in this process, or accelerate it, we call it "restoration." 8. Some organisms that are transported from "outside" the local "system" don't require what we recognize as a disturbance to survive and reproduce, apparently being adapted to the "undisturbed" conditions of the dynamically stable, "local" ecosystem, and colonize without significant change in the recognized habitat. Such organisms are clearly (or are they?) "invaders." For our purposes, in our opinion, for whatever reasons, they are. Certainly when "we" are the initial vectors. 9. Humans and elephants and mice and weeds can be notable change agents, but it's an observation based on the human time-scale and value system. Does Nature "care?" 10. Never mind. Just go out there and get those grants and have some fun! WT "It's turtles all the way down." --Anonymous At 07:37 PM 4/6/2006, Teresa Woods wrote: >Just wanted to touch in and express appreciation for a rewarding thread >on a difficult and important -- urgent -- problem. I've been reading >with rapt attention and am waiting a few more days until contributions >seem to have petered out, and I'll compile the citations and post them. > It will take some time to plow through and read all the articles, but >I'm really looking forward to it. > >Thanks again! >Teresa > >Teresa Woods >Graduate Assistant >Division of Biology >232 Ackert Hall >Kansas State University >Manhattan, KS 66506 >785-532-9834 >[EMAIL PROTECTED]
