By Tony Hallam
Great up to date directory of major extinction occasions in earth historical past and disertion at the major nonetheless accredited theorites explaining approach those occurred. No colossal novelties or radical thoeries yet a few issues have been new for me just like the frozen methan gases gathered in large cuantities within the backside of chilly seas and the prospective climatic adjustments which may be cuased by means of them in the event that they are realesed to the atmospher via better ocean water temperatures.
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Extra info for Catastrophes and Lesser Calamities: The Causes of Mass Extinctions
Whole groups of species may exhibit such stasis before they change together, a phenomenon that has been termed ‘coordinated stasis’. The speciation event is presumably related to signiﬁcant environmental change, after a long period of boredom, to use Ager’s phrase. This leads us on to the subject of mass extinction, on both large and small scales. Ironically, while Ager remained until his death an enthusiastic neocatastrophist as regards geological processes, he persisted in his belief that mass extinctions, which perhaps could have provided some of the best evidence in support of his position, were gradualistic phenomena.
He dismissed palaeontologists as being not proper scientists but mere stamp collectors. This comment recalls Ernest Rutherford’s remark early in the twentieth century. When asked about what constituted science, he replied that there was physics, chemistry, which is a sort of physics, and stamp collecting. Thus the whole of biology as well as geology was airily dismissed, to say nothing of the social sciences. If one replies that today Rutherford would, perhaps grudgingly, concede a place at high table for molecular biology, what about the type of research that Darwin engaged in?
There has since been a huge increase in the sophistication of the mass spectrometers that are employed, and in the variety of radioactive isotopes used, with a corresponding increase in both precision and accuracy of the dates established, but there have been no striking changes in the Phanerozoic timescale. Thus Holmes arrived at a date of Evidence for catastrophic organic changes in the geological record 27 about 500 million years for the base of the Cambrian, whereas today the ﬁgure of 540 is generally accepted.