carnes@gargoyle.UUCP (Richard Carnes) (09/25/86)
[This article contains no philosophy. But in the 17th century it would have been described as "natural philosophy". Follow-ups are directed to net.sci.] [wex@milano.UUCP] >I seem to recall that experts now think that 98% of all species are >now extinct. It is hard to believe figures for species extinction >from the past because the information from that time is so poor. >Most species were not even known; how would we determine how many >species died out from say 1700-1799? There is evidence for species >known today but how does that compare with the past? Records of the disappearance of birds and mammals have been reasonably accurate since about 1600. Around 130 bird and mammal species became extinct between 1600 and 1975. In 1600 there were about 12,910 species of birds and mammals, and on this basis the average rate of extinction during this period is estimated to be 5 to 50 times as great as the average rate during the prehistoric past. [Sources: Fisher, Simon, and Vincent, *Wildlife in Danger* (1969); Ehrlich et al., *Ecoscience*.] No one knows or will ever know the exact number of species of all types of organisms that have become extinct since 1600. One difficulty is that we don't know how many living species there are even within an order of magnitude. About 1.6 million species have been catalogued and described, but this is probably well under half of the total. E.O. Wilson writes [*Biophilia* (1984), pp. 121-122]: Extinction is accelerating and could reach ruinous proportions during the next twenty years. Not only are birds and mammals vanishing but such smaller forms as mosses, insects, and minnows. A conservative estimate of the current extinction rate is one thousand species a year, mostly from the destruction of forests and other key habitats in the tropics. By the 1990s the figure is expected to rise past ten thousand species a year (one species per hour). During the next thirty years fully one million species could be erased. For the latest on prehistoric extinction rates, see David Raup's article in one of the March 1986 issues of *Science*. (Raup is the author of *The Nemesis Affair*.) Richard Carnes
carnes@gargoyle.UUCP (Richard Carnes) (09/29/86)
The following article by Philip Shabecoff appeared in the New York Times of September 28, 1986. ___________________ WASHINGTON, Sept. 27 -- Scientists and conservationists are urgently calling for worldwide action to slow the accelerating mass extinction of animal and plant species. At a conference this week called by the National Academy of Sciences and the Smithsonian Institution, speaker after speaker reported that human activity, particularly the rapid destruction of tropical forests, was dangerously reducing the earth's biological diversity. Many of them warned this loss threatened future human food and drug sources and, according to several speakers, might even threaten the current level of civilization. They also said thousands of species were disappearing each year without humans' ever discovering them or their potential for helping humanity. Many urged that international science give a high priority to finding and describing existing species before they disappeared forever. Dr. Edward O. Wilson, professor of science at Harvard University, noted that 1.6 million to 1.7 million species of plants, vertebrates, invertebrates, fungi, algae and micro-organisms had been classified. But he added in an interview that estimates of those that had not yet been described ranged from 5 million to 30 million. His own rough estimate of the number of species that are now vanishing each year is "10,000 and increasing." Dr. Wilson and other speakers said that the loss of species would soar in the next century as human population expanded. The World Bank estimate is that the number of humans will reach a plateau of 11 billion in the year 2050. Norman Myers, a consultant on environment and development, said an impending "extinction spasm" was likely to produce "the greatest single setback to life's abundance and diversity since the first flickerings of life almost four billion years ago." Other speakers said the current rate of species extinction caused by human activity was paralleled only in major geological and climatic upheavals that changed the earth in the distant past. Dr. Paul R. Ehrlich, professor of biological sciences at Stanford University, said habitat destruction, including paving, plowing, logging, overgrazing, flooding and draining, was the chief reason so many species were now "on the road to extinction." Toxic substances introduced into the environment and climate changes caused by human activity are also hastening the extinction of species, he said. He noted that although human beings [are] only one of at least five billion [sic -- should read "million" -- RC] species on earth, their activities consumed at least 30 percent of the energy converted into food for living organisms through plant photosynthesis. At the projected rate of population growth, humans would use about 80 percent of this biomass within the next 100 years, he said. "Those who think that the human population can double its size again need to contemplate where the basic food resource will come from," he said. If the current trend continues, Dr. Ehrlich said, "humanity will foreclose many of the direct economic benefits it might have withdrawn from earth's once well-stocked genetic library." Among the possibilities that might be forgone is a cure for cancer from some organism as yet undiscovered. Worse, he said the genetic losses would cause the entire ecological system on which humanity depends to falter. "Humanity will bring upon itself consequences depressingly similar to those expected from a nuclear winter," he warned, including famine and epidemic diseases. Dr. Ehrlich and other participants said that one essential step in slowing the loss of species must be to slow and perhaps even reverse the expansion of the human population. Dr. Thomas Lovejoy, vice president of the World Wildlife Fund-U.S., said that there was now an urgent need to "map the earth's biology" and urged that scientists construct "a new era of biological exploration." F. William Burley, senior associate of the World Resources Institute, a research and policy group here, said destruction of the earth's major ecological systems must be stopped and urged support for a global "tropical forest action plan," developed by more than 60 countries along with international organizations [and] nongovernmental groups. He said that agriculture must be "improved and intensified" so that hungry people will not have to cut down tropical forests to grow food. Forestry management also needs to rehabilitate damaged forests and prevent wide destruction of existing forests, he said. He urged that the wealthy industrialized nations reorder their economic priorities and concentrate on programs that would save the earth's ecological systems and the species that dwell within them. Dr. Wilson of Harvard said, "In the end, I suspect it will all come down to a decision of ethics, how we value the natural world in which we evolved and now -- increasingly -- how we regard our status as individuals." To Dr. Ehrlich, to look to technology for the answer to the loss of biological diversity would be "a lethal mistake." He said that some steps could be taken to ameliorate the crisis but that what was needed is "a revolution in attitudes toward other people, human numbers, what human life is for and the intrinsic value of organic diversity." "Scientific analysis points, curiously, toward the need for a quasi-religious transformation of contemporary cultures," he concluded. ____________________ Richard Carnes
colonel@sunybcs.UUCP (Col. G. L. Sicherman) (10/02/86)
> No one knows or will ever know the exact number of species of all > types of organisms that have become extinct since 1600. One > difficulty is that we don't know how many living species there are > even within an order of magnitude. About 1.6 million species have > been catalogued and described, but this is probably well under half > of the total. It's sometimes a matter of taste whether to classify two organisms as different species or just different varieties of the same species. With livestock or trees it's easy to decide; not always so with bacteria or viruses. In the course of evolution, species sometimes merge or split; then how do we keep score? There's only one species whose impending extinction worries me. It's the one that forms prayers to broken stone.... "Although men are not laboratory animals, they often behave as though they are." --Eric Berne (1972) -- Col. G. L. Sicherman UU: ...{rocksvax|decvax}!sunybcs!colonel CS: colonel@buffalo-cs BI: colonel@sunybcs, csdsiche@sunyabvc
mrh@cybvax0.UUCP (Mike Huybensz) (10/05/86)
In article <1056@sunybcs.UUCP> Col. G. L. Sicherman writes: > It's sometimes a matter of taste whether to classify two organisms as > different species or just different varieties of the same species. > With livestock or trees it's easy to decide; not always so with > bacteria or viruses. In the course of evolution, species sometimes > merge or split; then how do we keep score? Actually, it's not easy to decide even for well known animals and plants. As you might expect, there is a continuum of degrees of variation between populations, and as time passes, our tools for discerning the smaller but significant variations improve. For example, the common leopard frog of the eastern US was thought to be one species until about 10 years ago when it was discovered to be at least four, each with distinctive mating songs that provided reproductive isolation. The exact score isn't too important: the idea is to measure the genetic diversity by assuming that number of species is roughly representative of genetic diversity. However, the species numbers of smaller organisms are badly under represented because we can't yet effectively distinguish them from eachother. These cryptic species are a major taxonomic problem. In my own field, the mites, there are groups which are well known to be chaotic: because the animals all look extremely similar, but won't interbreed. Eventually we may be able to look directly at their genetic diversity and finally resolve these questions, but in the mean time we are probably dreadfully underestimating just how much diversity is out there in very small packages. -- Mike Huybensz ...decvax!genrad!mit-eddie!cybvax0!mrh