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  #1  
Old 06-14-2009, 12:47 PM
agentorange4tang agentorange4tang is offline
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How many animal species become extinct everyday?

So i'm a big fan of Daniel Quinn's work (Ishmael, My Ishmael, Story of B, etc.), but one thing that tends to irk my goat about him is that in much of his writing, he claims that "as many as 200 species of animals become extinct everyday." I don't know why, but this information feels like complete bullshit. On his website, he addresses the issue:

I've made mention of daily extinctions in many different places, always qualifying it as an estimate. If "as many as 200 species" become extinct every day, this may mean that 55 species became extinct yesterday and that 178 became extinct today. I've asked conservation biologist Dr. Alan D. Thornhill if he knows the origin of the original 200 estimate. He said he was certainly familiar with it but could not point to a particular source for it (though it seemed to him not an unreasonable estimate). In May, 2007 Ahmed Djoghlaf, head of the U.N. Convention on Biological Diversity, said that "Extinction rates are rising by a factor of up to 1,000 above natural rates. Every hour, three species disappear. Every day, up to 150 species are lost." So at last we have a pretty authoritative estimate–but of course it IS just an estimate. There is no exact way to keep track of the surviving populations of millions of species.

Every day, up to 150 species are lost??!! How do they know that? What's everyone else's opinion?

Last edited by agentorange4tang; 06-14-2009 at 12:47 PM..
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  #2  
Old 06-14-2009, 01:01 PM
shallora shallora is offline
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Sounds like complete and utter bullshit to me.

Scientists estimate there is something between 5 million and 30 million species on earth
http://www.eoearth.org/article/Biodiversity

So let's say there are 17 million species on earth, just to plot it right in the middle.

200 species per day = 73000 species per year

So if there are 17 million species on earth, and we lose 73000 whole species per year, that means in 232.8 years there not be a single living organism on earth. No animals, plants, humans, fungus, NOTHING in 232.8 years. Earth will just be a bald, powdery rock in 232 years, just like the Moon.

Sounds like utter bullshit to me. Some environmentalist probably pulled that extinction rate out of his arse just to so that he could sing Kumbaya at a Greenpeace rally one year, and the figure has since taken on a life of its own.
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Old 06-14-2009, 01:19 PM
Colibri Colibri is online now
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Originally Posted by shallora View Post
So if there are 17 million species on earth, and we lose 73000 whole species per year, that means in 232.8 years there not be a single living organism on earth. No animals, plants, humans, fungus, NOTHING in 232.8 years. Earth will just be a bald, powdery rock in 232 years, just like the Moon.
Of course, nobody is proposing that current high extinction rates will continue until everything is gone. The most vulnerable species (those with very small ranges, and those particularly susceptible to environmental change) will be lost first. Once those are gone, the more resilient species will be left.

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Sounds like utter bullshit to me.
Mainly because you don't know anything about the subject.

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Some environmentalist probably pulled that extinction rate out of his arse just to so that he could sing Kumbaya at a Greenpeace rally one year, and the figure has since taken on a life of its own.
I am not going to argue in favor of the "200 species a day" figure myself. That seems high to me. But estimates of current extinction rates are not generated out of thin air. They are based on calculations based on estimates of the current number of species; what percentage of species have small ranges or are otherwise vulnerable; the rate of habitat loss; and the species-area curve.
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Old 06-14-2009, 05:14 PM
barbitu8 barbitu8 is offline
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A birdwatcher, by avocation, and a professor of biology, by vocation, once told me, when we discussing the possibility of the continued existence of the ivory-billed woodpecker (I'm a believer, and he is not) that 90% of all species that ever existed are not extinct. Hence, he maintained, why not the extinction of the ivory-billed? Which is no proof either way.
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Old 06-14-2009, 05:27 PM
Colibri Colibri is online now
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Originally Posted by barbitu8 View Post
A birdwatcher, by avocation, and a professor of biology, by vocation, once told me, when we discussing the possibility of the continued existence of the ivory-billed woodpecker (I'm a believer, and he is not) that 90% of all species that ever existed are not extinct.
You seem to have inadvertently included a "not" there. In any case, it's probably more like that 99.9 percent of all species that have ever existed are now extinct.

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Hence, he maintained, why not the extinction of the ivory-billed? Which is no proof either way.
Extinction is a natural process, and all species eventually become extinct. The problem is - and this is the general consensus of biologists who have looked at the problem - that the current extinction rates for well-known groups such as birds and mammals is estimated to be 100 times higher or more than the "normal" background rate as estimated from the fossil record. We don't know what they are for groups in which most species remain undescribed, such as insects or fungi, which are far more numerous.

This reference describes some of the ways that modern extinction rates have been estimated.

Last edited by Colibri; 06-14-2009 at 05:28 PM..
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Old 06-14-2009, 06:02 PM
Mangetout Mangetout is offline
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Q: How many animal species become extinct everyday?

A: None - they typically only become extinct on one occasion.
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Old 06-14-2009, 07:16 PM
DrDeth DrDeth is offline
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Originally Posted by agentorange4tang View Post
Every day, up to 150 species are lost??!! How do they know that? What's everyone else's opinion?
A fair number of those "species" are small populations of beetles, some of which have not been "discovered' yet. Beetle specialists or "Coleopterists" are among the biggest "splitters" in the Biology game, ready to name a "new species" where other specialists would perhaps call it a population or a sub-species.

To over simplify it, let us say there is a beetle in the Amazon drainage that normally has 4 spots. There is a variant of this species that has 3 spots that lives on a small island in the middle of the Amazon. Nothing other than the # of spots is different, and there's only a few of these beetles on this little island . The small island floods out, the "3 spotted beetle" is not seen again. That is an "extinct species" to the beetle specialists.

Coleopterists estimate there may be up to 8 million undiscovered species of beetles (there are about 350K "known" "species"). So, you see every time another few square miles of rainforest is burned and cleared, there must be a few of those 8 million "3 spotted beetle" populations that gets eliminated. We maybe lose something like 20000 sq Meters of Amazonian rainforest every year, thus we must necessarily lose quite a few of those "undiscovered species of beetle, etc" every year (plus perhaps a few "known species"). There are also quite a few other insect etc specialists and some have given similarly (inflated ?) estimates of undiscovered species.

Few large, visible, successful and known species have become extinct in the last few years from what I can see here, in the North American area, it was the Carolina Parakeet and the Passenger Pigeon,both gone almost a hundred years ago http://en.wikipedia.org/wiki/List_of..._North_America
).

The "extinct species" are mostly smaller species and subspecies, limited in area and numbers originally, or as Colibri sez "the most vulnerable species". Of course, some of those could be very important anyway. Us humans have been very good at saving the larger, more visible species in the last few decades. Of course, we were the cause of much of the near-extinctions in the first place.

However, the amount of deforestation is a highly disputed figure, and so is the number of "undiscovered species" (some estimates range as high as nearly 100 million possible species). But if one takes the largest gloom & doom estimate of both, then yes, that figure could be correct. There is no doubt that deforestation and other human factors is causing the extinction of too many species way too fast - it is how many and how fast that is in dispute.

Last edited by DrDeth; 06-14-2009 at 07:17 PM..
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Old 06-14-2009, 07:37 PM
Contrapuntal Contrapuntal is offline
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Quote:
Originally Posted by Mangetout View Post
Q: How many animal species become extinct everyday?

A: None - they typically only become extinct on one occasion.
Oddly enough, it's usually right before vespers.
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Old 06-14-2009, 10:26 PM
Colibri Colibri is online now
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Quote:
Originally Posted by DrDeth View Post
A fair number of those "species" are small populations of beetles, some of which have not been "discovered' yet. Beetle specialists or "Coleopterists" are among the biggest "splitters" in the Biology game, ready to name a "new species" where other specialists would perhaps call it a population or a sub-species.
This is not correct in my experience, and I know quite a few insect and other taxonomists. Coleopterists are not more prone to split than other scientists. It's just that there are an ungodly number of undiscovered beetles, many of them quite distinctive, even to the generic level. (Some people say that if birds were beetles, taxonomists would put them all in the same genus, such is the level of morphological diversity found in some beetle genera.)

I'm currently working on an exhibit on newly described (since 2000) and undescribed species from Panama. One of my insect specialist friends went through the insect collection here with me, and easily picked out about 40 species of beetles that he believed to be not yet undescribed. Many of them were represented by a single specimen; insect taxonomists are reluctant to describe new species on the basis of single specimens.

Genetic work is revealing a huge amount of hidden biodiversity. Last night I was talking to a friend of mine who is a fungus specialist. She had just analyzed the genetics of 3000 samples of fungi that live inside the leaves of tropical trees. About 65% of the samples had unique genotypes, not represented in the other samples. Most of these represent undescribed species.
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Old 06-15-2009, 12:03 AM
DrDeth DrDeth is offline
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Quote:
Originally Posted by Colibri View Post
This is not correct in my experience, and I know quite a few insect and other taxonomists. Coleopterists are not more prone to split than other scientists. It's just that there are an ungodly number of undiscovered beetles, many of them quite distinctive, even to the generic level. .
Well, Ok, you work with those dudes and I don't. Still Coleopterists claim there are an awful lot of undiscovered beetle species, and that is certainly part of where the claim of so many animal species going extinct every day is coming from. Can we agree on that?

Of course insects do make up around 75% of the current figure of c. 1,250,000 total known animal species.
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Old 06-15-2009, 12:11 AM
MOIDALIZE MOIDALIZE is online now
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How many animal species come into existence every day?
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Old 06-15-2009, 01:25 AM
Askance Askance is offline
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There's quite a space between "everyday' and "every day".
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Old 06-15-2009, 09:05 AM
Colibri Colibri is online now
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Originally Posted by DrDeth View Post
Well, Ok, you work with those dudes and I don't. Still Coleopterists claim there are an awful lot of undiscovered beetle species, and that is certainly part of where the claim of so many animal species going extinct every day is coming from. Can we agree on that?
True. Beetles make up something on the order of 25% of all known animal species, so any calculation of extinction rates has to take them into account.

And coleopterists claim there are an awful lot of undiscovered beetle species because there are an awful lot of undiscovered beetle species. I can go out almost anywhere in Panama and easily collect beetles that have not yet been described (and have done so).
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Old 06-15-2009, 09:10 AM
Colibri Colibri is online now
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Originally Posted by MOIDALIZE View Post
How many animal species come into existence every day?
Genetic studies suggest there is a wide variation in the time it takes to generate species, from perhaps a few tens of thousands of years (except for rare cases of very rapid speciation) to millions of years. In contrast, it doesn't take very long for species to become extinct. While the number of new species being generated today is unknown, unless the rate of speciation has become accelerated over the background rate to the same extent as that of extinction, which is highly unlikely, species diversity is going down.
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Old 06-15-2009, 02:16 PM
barbitu8 barbitu8 is offline
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Originally Posted by Colibri View Post
You seem to have inadvertently included a "not" there. In any case, it's probably more like that 99.9 percent of all species that have ever existed are now extinct.
That "not" should have been a "now," which is superfluous. He probably did say 99.9%, but I found that so unbelievable I couldn't remember correctly.
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