Admittedly I am way out of my league here. One of my favorite books of all time is Richard Dawkins’ The Selfish Gene. It should be one of 20 books that every student who is considered educated should have read by the time they leave college. In any case, the book should be of fantastic interest not just to biologists but to social scientists, political theorists, and more. He spends a good deal of time early in that book discussing why theories of group selection are simply not right, and in doing so there is a good deal of discussion as to why the “selfish” entity is really the fundamental unit of heredity, the gene, and not supra-genetic entities.
With that in mind, let’s turn our attention to an issue that is getting increased attention in the environmental community these days – that we are in the midst of a great Sixth Mass Extinction at the moment. Let’s not have a debate about whether it is happening or not. To do that we would want to talk about background rates of extinction, we would want to talk about rates of speciation (i.e. the creation and emergence of new species), we would want to talk about measurement issues and so on. It does seem that species extinction rates are abnormally high, even though our understanding is pretty limited.
What goes unspoken most of the time when we are talking of species extinctions is, “so?” That sounds crass, but it certainly appears to be the case that for humans, they do not view “species” the way that these scientific papers seem to suggest they ought to. When examining existence values, economists tend to find that people treat many species as substitutes for one another. So, for example, while our willingness to pay to protect the snail darter may be high, that really is a stand in for, “we really want to make ourselves feel better about not letting SOME living species die off.” Once we dig deeper and understand whether the willingness to pay to protect a snail darter also extends to a desire to protect a similar species as well, or perhaps a bunch of beetles, it turns out that we are not willing to do that much more to protect them. So, “protecting the snail darter” is not really about protecting the snail darter.
Continuing on with the “why?”, if you were to ask folks to think more, they might say we should protect more species so that we can get some extrinsic utility from them – future medicines, future materials, and so on. If we continue to ask, we would surely get some answers that suggest intrinsic motivations – getting pleasure knowing that such a species exists and is doing well is surely a good justification. And so on.
But taking things to an eco-biological perspective, let’s reask the question why. Do we worry about species extinctions because there is an intrinsic value to this kind of biodiversity and the ecosystem services that various species provide? Undoubtedly yes. But in reflecting on the writings of Dawkins and the insights of genetics – why is biodiversity important? What we know, and this is pretty orthodox stuff, is that the “diversity” that matters is not really at the species level. The kind of diversity that matters for evolution to “work” is genetic diversity. A population of clonal plants or animals is going to find itself very much at risk of going extinct because the lack of mutations in its DNA means that it will not have any (accidental) traits that may make it suited to dealing better with changes in its environment. Remember, too, that DNA (ergo genes), is simply a chemical compound. The DNA that rests in you and me is in no way different than the DNA that is resting in a rattlesnake (chemically speaking) which is no different than the DNA that is embedded in a single-celled organism. That DNA (a nucleic acid) can transcribe RNA copies (nucleic acids) which in turn will be used to synthesize proteins (translation). Nothing in this process is unique or parochial. In other words, if you were to take a DNA sequence from one creature, it can be copied, read and used to produce proteins in other creatures. There is nothing “unnatural” or “good” or “bad” about this – this is simply how basic biochemistry works.
Now, in thinking about why we care about species extinctions, it should be pretty evident that it is not the bodies of a particular species that is particularly important biochemically. Those bodies may provide enjoyment, or as a byproduct produce some ecosystem services we care about. But notice in the environmental literature on extinctions, even the ecosystem services values are under-discussed or neglected altogether. We seem to be asked to care about species simply because “more is better.” But more is neither better nor worse – that is a biological head fake. What matters biologically is whether there are copies of the relevant DNA sequences around, and whether there are mechanisms in place to transcribe and translate that DNA into other organisms. But the entire point of THAT exercise is NOT to promote the awesomeness of some fuzzy and cool creature (as cool and awesome as that actually IS), but rather to promote the movement of particular DNA sequences into future “generations.”
So, the reason to “care” about species extinctions, really, if we are going to be naturalistic about it, is really to preserve biochemical diversity. Now, that is not exactly an attention grabber, and I understand that. But it sure would be nice if at least some lip service were paid to the fundamentals of evolutionary biology in either the original papers (like the one linked to above) or the news reporters breathlessly reporting scary statistics from said papers (e.g. “Over 1/3 of all species declining!”).
Of course, as I said above, this is beside the point of whether these changes are more significant at the macro level, and whether in fact there are increases occurring in other species ranges. For example, in the paper above, you will see extensive discussion of the number of species that are declining. You will not see a chart of the number of species expanding (and if 1/3 are declining, that means 2/3 are not) or the number of new species being created.
You should take these papers seriously nonetheless, but one wishes that the entire scientific and cultural debates we are having these days would enable such papers to be written and reported upon in a much more scientific manner.