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mass extinction    
roundtable:a modern mass extinction Watch Show 3:
"Extinction!" on PBS
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select a question from below
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: 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?
Panelist Responses: < back to intro page
Ariel Lugo
I think Darwin would favor the Endangered Species Act because he's a biologist, and I feel that biologists probably all endorse [the] Endangered Species Act, because it's the only thing we have to ensure that we pay attention to these species that are in peril.

And with regard to the money, I would say that the amount of dollars that go into the Endangered Species Act are minuscule compared to the expenditures in other aspects of the federal budget. Yet, even though those monies go into a small number of species, they help a lot of species, because by protecting certain endangered species, which are usually charismatic and are usually keystone species, you're protecting many other species that utilize those habitats. So, in spite of all the headaches that the Endangered Species Act gives to federal bureaucrats, I think, overall, it's positive.
Tundi Agardi
I think there's a couple of things that people should understand about the Endangered Species Act in the U.S., and also the other kinds of legislation that are emerging around the world where people have looked at the U.S. example and have seen the benefits of the Endangered Species Act.

One thing is that it's really a safety net, that it is meant to be a kind of option of last resort. And the fact that there are relatively few listings, given the number of species in the United States, in the Act isn't a signal that extinctions are not a serious threat to the biota of the United States and North America, but rather that we've only had to use that safety net in certain cases. We have a lot of other kinds of environmental legislation that help us prevent things from getting to the point where we need to invoke that very kind of extreme measure of providing individual species with this level of protection.

I don't think that any of us would argue that the absolute number of species is important, and I think there are very important decision-making processes that are behind the way that we craft laws and regulations and also determine the amount of money that we spend to try and recover those species that are faced with extinction.

So rather than the absolute numbers, I think the alarming thing with the Endangered Species Act -- and the fact that we have to use it at all -- is that when we're actually at the point of using that safety net and listing individual species as threatened with extinction, we're actually saying a lot more than that there is a species that has been reduced to a certain population level from which it is not likely to recover unless there's an enormous amount of investment of time and energy to protect it.

And that broader statement that we're making by listing species is that in fact the habitats that support those species are endangered. And so, often, the species that are listed are really emblematic, or kind of flagships, for unique habitats that are being lost across the country and, of course, around the world at the same time.

So, in answer to the question about whether Darwin would support the Endangered Species Act, I think absolutely so, not only because it helps to keep those species around and ensure their future, so that they don't disappear from the world forever, but it also, at the same time, helps us to prevent the loss of unique habitats which support these species.
Peter Ward
There's a sense of, What is the value of species, and therefore, why save them? And the things that I keep seeing most often are that perhaps those very species can provide enormous benefits to humankind through medical herbs; then there are species which keep various ecosystems that are of value, again, to humans. Sometimes, it's just because they are charismatic.

But again, taking the longer view: If we were to go back about 63 million years ago and look at a very tiny rat-sized mammal that would give rise to all of the rest of the primates, it would be very difficult for us to say, Well, there is the future of intelligence on this planet. That tiny rat-sized creature would look anything but intelligent.

The point, to me, is that species not only have an inherent value in the present day, but they have a future, that we cannot tell where the next global intelligence, if there's going to be one, will come from. We do not know what species will give rise to some charismatic group, or some very important group. If we take the long view, the millions-of-years view, then we must not only think about species' value, but future species' value.
Daniel Simberloff
I believe the question has a faulty assumption. As you stated it, the question was, Is the money being spent on species doomed for extinction? And the performance [of the Act] shows that [listed] species are not doomed to extinction. As Tundi said, the species listed under the Act are almost always cases that are already greatly damaged, from a population standpoint. Since the Act was passed, in 1973, approximately 1,600 species have been listed. Of those, only 24 have gone extinct, and it's believed that 11 of those were actually extinct before they were listed. They were listed, in the early days of the Act, sort of on the off-chance that they might still be around, as a way to save the habitat they would be in if they were.

And most people who have looked at this question very carefully, species by species, believe that without the Act a good 200 or 300 would already have gone extinct. So they're not doomed to extinction, and the Act has been quite effective.
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