Biology in the News Explained

Are humans natural?

A post at the invasive species weblog sums up a lot of the important issues surrounding invasives. One of my favorites for class discussion in my invasive species course is number 8: What is the definition of natural? Seems easy to define on the surface, but murky waters lie beneath. And the answer to this question is so incredibly important to how we regulate, control, and even think about species assemblages.

Difficult questions: Is everything humans do unnatural? Are only some things humans do unnatural? Why? There are some purists who fiercely contend that because humans evolved on this earth as every other species did, whatever we do is an extension of natural processes. The problem is that the logical conclusion of this particular natural process is the extinction of the majority of species on this planet. Of course for us ecologists, this is a painful idea, because we have built careers on our fascination with the diversity and complexity of life. Perhaps for most laypeople that appreciation just isn’t there, and so I’m simply biased. One analogy I like to imagine is that of the linguists out there witnessing the extinction of hundreds (thousands?) of the world’s languages as different cultures are wiped out or assimilated. Like species, they cannot be brought back. But for me the idea of lost languages is not emotionally charged as is the idea of lost species.

So I have to justify my belief that the movement of species around the globe by humans is an unnatural process, because it results in the loss of biodiversity. But I continue to struggle with the philosophical question of whether biodiversity has inherent value, or only a value imposed by humans (in the sense that gold and diamonds have value). Because I am human, I cannot answer this question completely. Biodiversity does have value to me, because life itself is awe-inspiring. Habitat diversity, an extension of biodiversity, is similarly important – i.e., India looks different from South Africa which looks different from Antarctica. This is partly what gives us our “sense of place” as so eloquently presented by Jeff Lockwood at the University of Wyoming. Many of us are disheartened by the strips of chain stores that characterize so many American cities now. (I literally have trouble remembering what state I’m in sometimes when cruising down such a strip.) The rapid, constant movement of species around the globe is resulting in the same phenomenon on the level of habitat. Look at the plants on most tropical islands these days, and they pretty much look the same, unless you find a really remote spot.

Such is the value of biodiversity to me. That’s pretty much why I fervently believe that nearly all post- (and some pre-) industrial movements of species are unnatural and destructive. Even in the best-case scenario, when native species are not destroyed, when alien species quietly integrate themselves into a habitat with no overt ecological impacts, the habitat still suffers slow death by a thousand cuts.

Unfortunately, as far as policy-makers are concerned, short-term economics trumps all. Which means we pay a lot more down the road for control of invasives than we would now for prevention of species movements. And we only bother paying for the control of those which have a current economic impact. In this country, protection of biodiversity is hardly on the radar. Even in Australia and New Zealand, which have much stricter controls than the U.S., the political force of “free trade” (I’ll leave the loaded definition of that term to the economists) is becoming overwhelming, with continual pressure to roll back what regulations there are. Which brings me full circle to a previous post.


10 Responses to “Are humans natural?”

  1. Georgfelis says:

    Directed here from TH.

    Kinda gotta define “Good”, while splitting up Cultural Diversity and Critter Diversity.

    Is it a Good Thing for a native of Flyspeck Island to maintain her own language, culture and such, when part of that culture is to have half of her children die within a year of birth, to believe that the earth is flat and travels around on the back of a giant turtle, and to speak a language that only a hundred other people speak? There’s quite a bit of debate there.

    On the other manipulative appendage, is it a good thing to have biodiversity in specific instances, i.e. if you are growing oranges, should you want a colony of Mediterranean Fruit Flies in the area? Generally yes, you want lots of happy chaotic genes out there mixing it up in God’s Big Test Tube, a thousand points of corn, soybeans and legumes of all types. But when you talk Cane Toads, Emerald Tree Boas, and Australian Rabbits, we can all agree a little diversity goes a long ways.

  2. biotunes says:

    Ah, but the reason that cane-toad type of ‘diversity’ is undesirable is because although in the short run the local habitat diversity is increased, it often results fairly quickly in a net loss of local diversity.

  3. doctorpat says:

    Why are you separating out these things as “natural or unnatural”? Surely there is already a classification (good and bad, or desirable and undesirable) and to try to squeeze them into “natural” is asking for confusion.

  4. GreenmanTim says:

    One cannot speak of either conservation or consumption without attending to the overarching question of values. By this I mean not merely value in the monetary sense, for there are qualitative vales that do not so easily compute on a balance sheet. Values are either intrinsic – the right of something to exist for its own sake regardless of its utility or impact on other things humans may value – or they are defined by our own species and inform how we perceive our environment and the choices we make about it. There was a heated debate along these lines last year at Gristmill, as I recall, which produced no easy resolution to the question.

    A dichotomy is frequently offered that either biodiversity itself has inherent value – and hence the full expression of this diversity is preferable for its own sake – or one concludes that throughout deep geologic time there is evidence on a global and region scales of periodic cycles of species richness and paucity, which given sufficient time lead to “relatively” rapid diversification after mass extinction. If one accepts these cycles as natural, one might also conclude that the current extinction event, driven in large measure by the activities of a single species on this planet, is part of the grand scheme of things and should not be resisted as “unnatural.”

    To conclude that given enough deep geological time, everything shifts around so we oughtn’t get all worked up about the impact of invasive species today or the anthropogenic causes of these invasions is a false premise.

    Rather, the perspective of deep time shows how dramatically different today’s movements and introductions of plant and animal species across wide spacial gaps are from the geologic record. Instead of taking place over many millennia and via specific land and water connections, today’s introductions can come from virtually anywhere and become dominant invaders displacing those varieties already present in an extremely short period of time. Likewise, the present extinction event is more global in scope than even that which followed the Chicxulub impact. Nothing in the geolocic record since the evolution of terrestrial life forms on this planet compares in this regard.

    As to whether every living organism should be permitted to thrive even when it may be a deadly virus or catestrophic crop pest, very few of those who advocate on behalf of biodiversity conservation have a problem with managing individual species that threaten the resources we value, and this includes human helath and wellbeing as well as broader ecological considerations. No one that I work with believes we need to reintroduce smallpox as a globally endangered organism worthy of conservation. But we are inclined to insist that human beings, the greatest change agent in this period of Earth’s history, make informed choices that look beyond the short term about what we choose to conserve and what we consume. We are, so far as we are aware, the only intelligence agent of global change to have acted on the world stage at this scale and magnitude. One does not expect an asteroid to choose where it impacts the surface, but our species has its much vaunted free will, and as such the question of both value and values is paramount.

  5. biotunes says:

    Couldn’ta said it better myself. Cheers.

  6. Assistant Village Idiot says:

    Over from TH -
    I agree that natural and unnatural are elastic enough terms to be of limited use in these discussions. You seem to be asking the “is it natural” question in order to answer deeper questions of what is right and justifiable. What would you hope to gain by deciding that human activity is natural or not?

    As GMT suggests, values questions come from many places. My current worry is that aesthetic questions are trying to masquerade as moral ones in (some) environmental debate. There are any number of outcomes for biodiversity which many would call catastrophic that move me not at all. After such catastrophies, will wine cease to cheer? Will the young no longer fall in love? Will the nurturance of children no longer give pleasure?

    We want our descendants to be able to move around in the environments which give us pleasure. But we disagree about which environments “should” give us pleasure. I love hiking in the White Mountains, but that pleasure has no especial holiness attached to it, nor any claim on those who prefer shopping at chain stores.

  7. Bill H says:

    I came here from TH several days ago and have thought about this.

    Basically you are asking if the effects of human activity would be natural if humans didn’t exist.

    You should not be asking “Are humans natural?” or even a definition of ‘normal’.

    What you should be asking is what are the differences between the nature of humans and the nature of other animals and why that difference makes a difference.

    Start with:
    Is that difference one of degree or one of kind?

  8. biotunes says:

    That is certainly another way of looking at it. But I’m not considering if humans didn’t exist – I’m considering that it is technology that makes the difference. In that sense, I believe it is a difference of kind as far as invasive species are concerned, because things can be moved around the globe several orders of magnitude faster because of technology.

    Even pre-tech humans were efficient at what they did. They caused a lot of extinctions when they invaded the New World from Asia. So in that sense perhaps tool making was the breakthrough that made us begin to exist outside of nature.

  9. Anonymous says:

    Marcelo from Sydney AUS.

    Firstly let me thank you for opening such thoughts to debate, I would like to comment and please excuse some of my clumsiness as i am not a very educated person.
    For many years I have thought of this same questions and i would like to air some of thoughts, to me human behaviour would be considerd un-natural if our species was not from this planet and therfor we would be a competing organisim in a new inviroment but this not being the case our total impact is completle natural .
    I dont belive the question posed is not difficultat all accepting it is another matter.
    Using technology as a mechanisim to justify un-naturalness undervalues our ancestors achivments, using globalisim also undervalues our ancestors achivments .
    Our Speciec has got to this point in earth history precisley beacuse of them.
    Using ideas of Modren men vs Aboriginal Cultures is also contraproductive to answering your question as all levle of human activity has changed the inviroment in wich it inhabited so it only beacome a question of degree of impact.

    There is a comon link with all living species on earth and that is one of surviveability in the inviroment that they find them self in , some will do better than other and some will be exctinc, so exctinciton is the rule and survial is the exception but for every extention a nich opens for somthing to fill it space.
    Biodeversity does not end with human impact it just changes the only problem is we do not have the time to see those changes occuring so we bring our values to the question.
    Im not a fatalist in the sence that i belive that human impact will destroy the earth as this is impossible for even human to do, having said that i can accept that we might destroy it for own species to survive and this behaviour is the rule in all speceiess .
    Although we too can change and current world discussion on such global issues as Global Warming/Biodiversity might produce changes to my previous stament it to happen if they included technology and commerce to achive it.
    In conclusion I would say that long after humans as a species would have left this inviroment the earth will continue to rotate around the sun untill such point that it to would be extinc and I can be certain that before that would happen the earth would be a total sterile inviroment, not fatlistic just a realist.

  10. Jaymaa says:

    Really this question is answered by yourself its all in your beliefs religious or none religious.myself I believe we evolved so everything is natural because it’s all made from the same thing earth


  1. Are humans natural? | Environmental Ethics in the Anthropocene - [...] Ecologist M. L. Henneman contends that human beings are not natural when our movement across the globe becomes so ...

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