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... Science Frontiers ONLINE No. 110: Mar-Apr 1997 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Cichlids Punctuate Equilibrium In those pesky cichlid fish of African lakes we may be seeing punctuated evolution during an actual punctuation. Responding to the article in SF#108 on the Lake Victoria cichlids, A. Mebane called our attention to Lake Malawi. While the Lake Victoria cichlids seem to have evolved a profusion of species in a space of about 12,500 years, those cichlids in Lake Malawi may have done the same in only a century or two. T. Goldschmidt advances this evenmore-abbreviated time scale in his book Darwin's Dreampond . In it, he discusses how the water level of Lake Malawi fell more than 120 meters ... the 1800s -- an exceptionally dry period in Africa. Today, the Lake is again high and once more host to isolated rocky islands, each with its own unique complement of cichlid fish; each island has species found nowhere else in the lake. Where did all these species come from, considering that their little islands were bone dry just a century ago? Goldschmidt writes: "Cichlids that inhabited these exposed rocks would have suffocated, unless they had already left for wetter climes. Yet today, species that do not exist anywhere else can be found near almost every rocky island. From an orthodox point of view, the most plausible explanation for this is quite surprising: many color forms as well as biological species developed over a period of less than two hundred years." This is ...
Terms matched: 2 - Score: 335 - 15 May 2017 - URL: /sf110/sf110p07.htm
... 'If much of the patterning of life's history is not set by Darwin's slow biotic mechanisms, then I think Darwin is in trouble. Is catastrophic mass extinction a major agent of patterning?' If so, 'impacts are a quirky aspect' of the process." Who is speaking within the single quotes above? S.J . Gould, a proponent of the punctuated equilibrium view of the evolutionary scenario. He added: "' The history of life is enormously more quirky than we imagined.'" In fact, the geological record shows so many quirk-inducing impacts that there is little room left for slow, plodding, uniformitarian evolution of the earth itself, life-in-general, and humanity. Mammals, for example, may not have ... the postulated (but now assumed factual) Cretaceous-Tertiary impact event simply because they were small in size - not smarter. (Kerr, Richard A.; "Huge Impact is Favored K-T Boundary Killer," Science, 242:865, 1988.) Comment. It now seems that Cassius was wrong about the stars when he was lining up Brutus to help assassinate Julius Caesar. And the "celestial" situ ation gets even worse below. From Science Frontiers #61, JAN-FEB 1989 . 1989-2000 William R. Corliss ...
Terms matched: 2 - Score: 129 - 15 May 2017 - URL: /sf061/sf061b05.htm
... Science Frontiers ONLINE No. 110: Mar-Apr 1997 Other pages Home Page Science Frontiers Online All Issues Last Issue Next Issue Sourcebook Project Sourcebook Subjects Contents Archaeology Circles of contention A NAZCA ZODIAC? Cracks in the kaimanawa-wall story? Astronomy The crstalline universe Martian life: act ii Biology Nannobacteria: life on a different scale Is oliver a "humanzee"? Cichlids punctuate equilibrium Sparrows at play Geology Did a methane burp down twa800? A METEOR IMPACT OR EARTH SLUMP? Geophysics Unusual circulating cloud object Unidentified light Psychology "PLANETARY VISIONS" DURING NDEs Mathenatics http://www.aros.net/angio/pistuff/piquer Alphamagic squares ...
Terms matched: 2 - Score: 129 - 15 May 2017 - URL: /sf110/index.htm
... progress' in life's history as the most puzzling fact of the fossil record. But I also believe that we are now on the verge of a solution, thanks to a better understanding of evolution in both normal and catastrophic times. We need a twotiered explanation for patterns (or non-patterns) in the history of life." The first tier of explanation involves the theory of punctuated equilibrium, as championed by Gould and Eldredge. Gould says he once thought that punctuated evolution would be sufficient to explain all of life's development, but that now a second tier seemed required; namely, a general theory of mass extinction or what catastrophism does to life and its development. (Gould, Stephen Jay; "The Ediacaran Experiment," Natural History, 93:14 ... February 1984.) Ediacaran life forms were typically flattish to maximize external area. From Science Frontiers #33, MAY-JUN 1984 . 1984-2000 William R. Corliss ...
Terms matched: 2 - Score: 126 - 15 May 2017 - URL: /sf033/sf033p08.htm
... stability is the rule, how do you get large-scale shifts in morphology? How do you get from funny little Mesozoic mammals to horses and whales? From Archaeopteryx to hummingbirds? (Kerr, Richard A.; "Did Darwin Get It All Right?" Science, 267:1421, 1995) Comments. (1 ) The reality of sudden saltations in the fossil record or "punctuated equilibrium" implies that those unfound transitional fossils beloved by the gradualists are truly missing. (2 ) The higher the taxonomic level, the more silent the fossil record. There are few clues as to how the major divisions of life (the phylla) originated. From Science Frontiers #99, MAY-JUN 1995 . 1995-2000 William R. Corliss ...
Terms matched: 2 - Score: 115 - 15 May 2017 - URL: /sf099/sf099b07.htm
