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extinction event:
Some people claim that we are living in the middle of another, man-made extinction event right now. However, humanity's effects are trivia compared with the extinction events shown in the fossil record.
Is that a fact? I've seen estimates on damage that are comparable to the smaller or intermediate sized mass extinctions, if nothing like the boundaries that end the Mesozoic and Palaeozoic eras.
- If those are the same estimates that I've seen -- that something like 50,000 species a year are dying out -- they are not particularly reliable. The ones I've seen have all been created by organizations like the [Sierra Club]? and people like Al Gore and Paul Ehrlich who have large, flaming political agenda that such figures are constructed to support. Over the past 500 years, almost 90 per cent of the forest along the Atlantic coast of Brazil has been cleared. However, no one has found a single known species that could be declared extinct. According to the "mass extinction" figures, about half the known species in that Brazilian forest should have been lost.
- But if you can cite figures commonly accepted by paleontologists -- figures that, say, appeared in a peer-reviewed journal -- feel free to enter them! --The Epopt
Do a search for something like "current mass extinction" in google, and you will find a great number of hits, including articles in Nature and Science. It looks to me like the mass extinction view is closer to a consensus than to a minority of politically motivated views. At the very least there is enough here to remove the sentence from the article, which I'm doing.
This is obviously a controversial topic -- there is nothing like "consensus" in the scientific community -- and I am strongly on the side that says calling what's happening at present an "extinction event" to be listed with the Permian-Triassic extinction event is like calling a domestic quarrel a genocidal holocaust. It's bad, and should be stopped, but blowing it out of proportion is ludicrous. I will fully support and cooperate with presenting both sides of this issue, but please don't try to make it sound like "everyone (who is a true scientist) knows that we're murdering Mother Gaia."
- I said that it would be more accurate to say it is a consensus (why quotation marks?) then to pretend the data uncontroversially indicated the converse, as was done, not that it would be entirely accurate. We have had entire families of organisms (not mammals, things like molluscs) mostly depopulated over large areas if not actually rendered extinct, but I'm not interested in debating the point. Simply note that I never said we should make it sound anything like your terrible strawman, I simply said the partisan statement should be removed.
- Point taken. I am over-sensitive on this point, and I apologize for my stridency.
Can someone clarify what the rate of extinction needs to be in order to be comparable to something like the
Permian-Triassic extinction event? That event, according to the article, lasted on the order of 900,000 years (give or take 600,000 years), with some 70-85% of species dying out. Assuming there were something like 10 million (wild guess!) species at the time, this is an extinction rate of between 4 and 29 species a year, on average. This seems so low that it would barely be detectable if you were in the middle of it. --
Zundark, 2001 Nov 29
- Your wild guess is right on the money. About one million species of animals have been described. (86% are insects, including about 300,000 species of beetles.) Some biologists estimate that up to 50 million more remain to be discovered. Most estimates put the number of plant species at somewhere between 10 million and 30 million, with tentative consensus around 14 million. I have no idea how many more plants they think have not been found yet. So your point is very well-made -- if humanity continues its current rate of eliminating species for another million years or so, we will be as bad as whatever clobbered Earth at the end of the Permian.
- Though this is a case of the apparent support for one side being rather more destructive of the argument than helpful :) A million years at our current pace...wow, I'd never have guessed. I plan on filing this away in my cranium for future (currently vague) use. Probably "Want to know how bad the Permian extinction was" not "We humans aren't so bad", though.
I removed
from the list of Holocene extinction victims only because they are already included under
extinct birds.
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