Biologist E.O. Wilson has estimated that 27,000 species go extinct each year.?

Question

Biologist E.O. Wilson has estimated that 27,000 species go extinct each year. Some skeptics, however, point out that scientists have documented the disappearance of only 1,100 species over the past 500 years. Does this observation demonstrate that Wilson's estimate is inaccurate. Explain your answer.

Answer 1

While I was able to find the author, I could not tell which journal you are referring to in order to validate your claim or determine if Wilson was talking about eukaryotes, animals, or what.

Certainly 27,000/year would be a trivial number if including bacteria. Indeed, we don't even know how many bacterial species there are -- millions to be sure. (Although one could certainly argue the term species is fuzzy when applied to bacteria anyway.)

Additionally, the numbers stated would depend on the definition of "species" used. Wihle a few rules of thumb do exist (e.g. ability to reproduce), definitions of species are nevertheless human-imposed categories that have limitations, such as species coming into and out of existence, which is a continuous process. Also, what about horizontal transfer?

More importantly, the question that begs to be asked is, how many new species appear each year?

The appearance and disappearance of species is a normal part of evolution. We live in a ever-changing environment, which includes both abiotic and biotic factors, such as weather and predators, respectively. As the environment changes, selection pressures change, perhaps driving a species to extension. Dynamic selection pressure, combined with chance and genetic drift result in the accumulation of accepted mutations in populations. When the genome becomes sufficiently divergent due to reproductive isolation and time (a population bottleneck helps too), a new species is created.

Answer 2

Wow. Some people will read six words ("27,000 species go extinct each year") and think they then know enough about the the topic or the thesis to simply dismiss it.

His thesis is based on the number of species (both known and uncataloged) per square mile of habitat for a particular environment, and the rate of reduction of those habitats. Feel free to disagree or dispute his reasoning or facts, but don't just dismiss it as something pulled out of a hat. You don't get to be a professor at Harvard or a double Pulitzer-Prize winner by being an idiot.

(And incidentally, he's not the only biologist expressing extreme concern. Niles Elderidge, Paul Ehrlich, and Georgina Mace are three noted scientists also noting an alarming rate of extinction).

P.S., to Sciencenut ... it proves nothing that he is unable to name a species that went extinct last year. He is making a statistical statement about the sheer numbers, not the specific species. I can tell you that there were 15,000 people at a rally in Kyrgyszstan this year, but I could not give you the name of a single one of them (can you?) ... but that does not invalidate the statistic. And requiring "bodies" as evidence of mass extinction?? ... man, you really are an "expert" on the topic ... when you burn down a forest, how many "bodies" of now extinct species do you expect to find?

Answer 3

It demostrates how little we still know about the biological world we live in. Scientist cannot possibly know how many species go extinct because 90% (making up the percentage) we haven't classified. Therefore, species are probably going extinct without we ever knowing what it was in the first place.

E.O. Wilson estimate is not inaccurate but the fact that humans only know of 1,100 species over the past 500 years has no context because we don't actually know how many different forms of life exist in the first place!

Answer 4

1100 in the last 500 years!!! Way too low of a number! Between Hawaiian and New Zealand bird species alone that have gone extinct in the last 50 years already puts it up to about 30 species!
I believe the 27,000 is more realistic, when including plants, insects, mammals, fungi, amphibians, and reptiles! This number probably includes the extinction of organisms we have not even discovered yet.

Answer 5

I once heard a tape recording of someone who actually called him on the telephone and asked him to name a few species that have in fact gone extinct in the last year, and he couldn't name any. The person even pressed him to name "just one species" and he couldn't. I think that tells you a great deal. 27,000 per year is ~75 per day or ~one species extinction every 20 minutes. You would think there would be some dead bodies or some other sort of evidence to prove such a high volume.

Answer 6

I've read several of his books and am quite familiar with his reputation. He is not considered to be an alarmist, and his estimates are more likely to be on the conservative side unless he indicates otherwise. The man has been around and has studied the overall issue since before it was popular to do so. Skeptics usually have a different agenda.

Answer 7

Every time you shake a tree in a tropical forest, you'll find several species of beetle that were previously undescribed by science. I'd bet that Wilson is getting his estimate by taking the number of tropical forest trees cut down each year, and multiplying it by the number of undescribed species per tree, or something like that.

Answer 8

Considering that this guy knows his funding for research is based on scare tactics- that is, scare people, get money, scare more people with junk science then get even MORE money....

I'd say he's a modern day con artist

Answer 9

It demonstrates that someone is up the creek without a paddle.

Answer 10

Sciencenut;shut down, you been at the keyboard too long. Secertsause rebutted you too well.