daneeka

Not really, although some relativly recent literature has brushed on the idea. A paper by Mayden (2002) (On biological species, species concepts and individualisation in the natural world. FISH and FISHERIES 3: 171-196) I read a few months ago proposed a pretty good way of approaching the problem. He points out that the evolutionary species concept is perhaps the only species concept that is non-operational; that is, all other species concepts provide the researcher with clearly outlined criteria for when something is or is not a species. The evolutionary species concept is therefore one of the few concepts that can actually encompass all forms of organisms. From memory he essentially explains that species concepts should be used on a hierarchical basis with all species concepts acting a surrogates for the evolutionary species concept. In other words operational species concepts should be used where they are applicable for a certain kind of species but should come secondary, and work alongside, the evolutionary species concept. Don't ask me to clarify this because I read it a while back and still don't really fully understand what he was going on about But I can't really come up with an example of a universal method for applying species concepts actually being put into practice.

From what I understand a species concept is essentially a testable hypothesis; that is, the concept defines a species by describing certain attributes that, when tested against, provides the worker with an indication as to where it fits within taxonomic rankings. So the aim is to remove, as much as possible, subjective decisions from the worker. The criteria is hence 'operational' because it describes series of actions for achieving a result. I agree with you here; there is really no way to make the naming of species objective with a singular species concept. Life is so variable and ambiguous that it is conceptually impossible. I think that it is possible to make it objective though; we simply need to apply species concepts (there are over 20 of them remember) such that the operational criteria can actually be used. The biological species concept (which is what most people have described in responce to this post), for example, is hopeless when used to demarcate asexual or selfing populations. Why not restrict this concept, which is at the end of the day a nice concept, to taxa for which it is appropriate and thus use its operational criteria. I think the only reason why taxonomy is subjective is because we assume that a universal concept is possible; and because of the ad hoc usage of species concepts. Maybe instead of trying to develop a universal species concept, we should instead try to develop a universal means to apply the myriad concepts we already have - all of which a perfectly valid (although some can be synonymised) when applied to the appropriate life forms.

A species concept is basically a hypothisis that's used to demarcate seemingly distinct living populations from one another. In other words it's a definition; and it's purpose is to allow for distinct living populations to be defined objectivily (i.e. free from value judgements) by testing such populations against various opperational criteria. This is obviously of importance to taxonomy but also is a significant tool for ecology and biology. I was just wondering what people's thoughts were on what defines a species. There are over 20 concepts/hypotheses out there at present - as of yet no universally accepted concept has been developed - and each concept can yeild different results. Do species even exist?

I not sure if climate change will have any long term effect on the integrity of life on this planet: there have been five documented mass extinctions (the most extreme of which resulted in a 95% reduction of life on this planet) and life has continued...extinction simply results in increased rates of speciation. So biotic diversity will probably decline, and part of this decline will be influenced by global warming, but this is only a problem for people...not necessarily for the planet. Personally I think the inertia of human induced climate change is such that whatever we attempt to employ to retard further climate change is too little too late...we will simply have to learn to live with our mistake. Things will cool down again in another 140,000 years or so, maybe we'll get it right then...if we make it.

Yep I agree; It's quite easy to simply blame the nation in question but if you take a proper look at things you realise that the motives behind forest clearance can be traced back to governments and consumers within developed nations. Much of the produce derived from agriculture within undeveloped nations is exported to feed the developed world. These people need to make a living and untill we, as conscious consumers, provide the motivation for alternative means, such activities will continue. Global warming is as we are presently experiencing it is both a funtion of human activities and a natural phenomenon. The drivers behind both [factors] are yet to be fully underdtood. I think the bottom line is that cutting down vast tracts of forest is not wise but it is not up to government to prevent this...it is up to society.