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roundtable:a modern mass extinction Watch Show 3:
"Extinction!" on PBS
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First, a general question. Are we now in a mass extinction, and if so, why does it matter?
Some Web visitors wrote to say they have heard it said, especially of tropical and marine organisms, that we are losing species before we even know of them. And the question is, if we haven't discovered a species yet, how do we know that we've lost it?
Would Darwin support the Federal Endangered Species Act? Millions of dollars are spent by corporations and government for habitat conservation plans, recovery plans, etc., for species that seem doomed for extinction. Is this a wise use of money? Why or why not?
If extinction and mass extinctions are a natural part of Earth's history, should we really be concerned about our effects on endangered species? Are we trying to fight something that's inevitable anyway and that is much larger than us, as a single species ourselves?
I'm concerned with the loss of genetic diversity because it affects food supply, drug discoveries, and the stability of ecosystems on which we depend. And yet, I'm very skeptical of the theory of evolution as it now stands. How does the theory of evolution -- or we could also say that as evolutionary thought -- explain and predict what's going on with the current cycle of extinction, better than if we had to just rely on what we can observe? In other words, what context and what value does evolutionary thought provide to this discussion that we're having?
Several other questions relate to this: Loss of biodiversity, water and air pollution, and the greenhouse effect are all impacting the biosphere, and if these are indeed combining to produce a mass extinction, do you think our species will survive it? Peter's already said that he thinks yes. How about some other perspectives?
Let's move onto some more specific questions. Why do bigger species go extinct faster than smaller ones?
Do you feel that extinctions of large Ice Age mammals had any human causes?
Another Web user wrote: I know there is a gene databank under construction right now. Could this be used as a modern Noah's Ark for the future?
We'll wrap up with a different kind of question. There was one that came from a younger visitor to the Web site who asked, What can kids do to help save the rain forest and animals?
   

 

Q: Another Web user wrote: I know there is a gene databank under construction right now. Could this be used as a modern Noah's Ark for the future?
Panelist Responses: < back to intro page
Daniel Simberloff
Well, I guess most people that are thinking along these lines aren't thinking so much of the genes themselves as the possibility that tissue, even from non-reproductive cells, could somehow be used to reconstruct species, if the tissue is well enough preserved. There have been a number of suggestions about how we ought to be stockpiling tissue of species as they go extinct. I'm no expert in the technology, but I would hate to put my faith in it, for such an important issue.
Peter Ward
I'm certainly no expert in this field whatsoever, but taking a longer view -- I'm getting boring in this respect, I suppose -- but let us use as an analogy the great library in Alexandria and how it was not a gene database, but certainly a database for all the earliest literature from several thousands of years ago. And that's all gone. To make this work we have to put our faith into a civilization's continuing for millennia, as well. I really do believe that humans are going to last for a very, very long time. I think civilizations are going to rise and fall, and rise and fall.

For instance, I believe that it's completely inevitable that we are going to have another glacial interval. We're in an interglacial now, and the irony is everybody's worried about fossil fuels and global warming, and there will be a short-term pulse of global warming. But we've still got maybe another million years of Ice Age, during which glaciers will probably retreat and advance and advance and retreat. Can we expect civilizations as we understand them now to be able to survive such enormous perturbations, that a building containing all of these genes itself would survive? The hope is yes, but the practicality is that keeping such a base alive for 100 years may be possible, but for a millennium, I doubt it.
Tundi Agardi
I think, Peter, your longer view is a good one to have, and it puts us into the broader context of the way things happen in much larger time scales. But on the shorter view, I think, even if we were to have confidence in kind of cloning technology or other kind of technology that would allow us to bank organisms as they're going extinct and recreate them at some future point in time, we'd still be left with the problem of what do we do with these organisms, and how can we possibly recreate the habitats in which they lived? And it's not likely that we would be able to do so, so we would then be stuck with kind of a theme park solution, which would essentially be keeping animals in captivity.

I don't know what good that would do anyone, and I think it would be a rather depressing way to keep alive organisms that had suffered the fate of being in our way, whether inadvertently or being got rid of on purpose. So I think the technological solution is not really a solution, because we can't possibly recreate the kinds of environments that gave rise to these species and sustain them.
Ariel Lugo
I agree with both Peter and Tundi, but I would add, if you want to let your imagination run wild, then if you say, since these organisms are not going to be able, probably, to function in the new environments that we're creating, maybe this technological person would say, Well, then we'll build new organisms, and that's why we need those genetic materials. But then that gets into deep waters, into ethics and everything else.
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