How many cubits again?

Is every species of living thing on the planet equally deserving of protection?…


Seriously. No.

Some must be protected.
Some ought to be protected.
It’d be pragmatic, prudent or prescient to protect most.

A few I’d just as soon see dead. Very few.
Some actually don’t matter much either way, except in an abstract aesthetic sense.

Worst of all, the definition of “species” is biased towards charismatic species (we fine grain populations that look good, and coarse grain over populations we know little of or care little for); so at some deep level the question is poorly defined.
We should preserve biodiversity, to the extent we feasibly can; with the exception of a few bundles of genes we might want to pre-emptively annihilate.

(300 cubits long, in case anyone cared…)


  1. #1 marcelo
    July 15, 2006



    Every single one.

    Or can you tell us what the Earth would be like without a particular species of say spider?

  2. #2 Steinn Sigurdsson
    July 15, 2006

    Uhm, No.

    There are 37,000 or so known species of spiders, near as I can tell.
    A lot of them inhabit small specialised niches on isolated islands, and recolonization and niche competition is fierce – that is to say, if you were to remove most any one species of spiders confined to small isolated islands, there would be absolutely no effect on the Earth at all, and the ecological niche would most probably be rapidly reoccupied with a new species which would branch off from its parent species.

    Caveat: there may be some species of spiders which are critical to a broad niche and whose loss could cause a cascade of ecological damage. We don’t know enough to tell which those might be, though probably most spider species are not critical. Secondly, if you start losing a lot of spider species, then at some point there are no new populations to fill empty niches and serious ecological damage occurs – again, I don’t think the region of loss at which there is such damage is well known – we could most likely lose 1% or even 10% of spider species with little effect on ecosystem functionality, but a 90% loss would probably be devastating.
    This is of course a time dependent statement – recovery is more thorough over a longer (megayear) period.

    Similar arguments apply to other species – although if all clades are suffering losses, then perpetuation and restoration of ecosystem functionality may become harder – poke too many holes in a dense web and it unravels.
    This is quantifiable, but in detail we do not have either the data or the understanding of the quantitative ecosystem dynamics to draw hard lines.

    Caution is prudent, but infinite caution is impossible.

    Oh, proof by example: we certainly lost several spider species in the last few centuries during, for example, massive volcano eruptions on isolated islands. Earth carried on much the same.

  3. #3 etbnc
    July 17, 2006

    Unfortunately, in practice, the values expressed at the beginning of this post rarely lead to the goal expressed near the end: “We should preserve biodiversity”.

    In my experience, the values and attitude expressed by Marcelo’s comment are more effective at motivating behavior that leads to the stated goal of preserving biodiversity.

    Therefore, as a simple matter of practical strategy, I find it helpful to adopt Marcelo’s attitude.

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