Stephen Jones quoted:
>--------------------------------------------------------------------------
>"Zircon dating, which calculates a fossil's age by measuring the relative
>amounts of uranium and lead within the crystals, had been whittling away
>at the Cambrian for some time. By 1990, for example, new dates obtained
>from early Cambrian sites around the world were telescoping the start of
>biology's Big Bang from 600 million years ago to less than 560 million
>years ago. Now, with information based on the lead content of zircons
>from Siberia, virtually everyone agrees that the Cambrian started almost
>exactly 543 million years ago and, even more startling, that all but one of
>the phyla in the fossil record appeared within the first 5 million to 10
>million years. "We now know how fast fast is," grins Bowring. "And what I
>like to ask my biologist friends is, How fast can evolution get before they
>start feeling uncomfortable?" (Nash J.M., "When Life Exploded", Time,
>December 4, 1995, p74.
http://www.time.com/time/magazine/archive/1995/951204/cover.html
Wonderful article. I recommend everyone read all of it. Here's another
quote just a few paragraphs above Stephen's tidbit:
"What could possibly have powered such a radical advance? Was it something
in the organisms
themselves or the environment in which they lived? Today an unprecedented
effort to answer
these questions is under way. Geologists and geochemists are reconstructing
the Precambrian
planet, looking for changes in the atmosphere and ocean that might have put
evolution into
sudden overdrive. Developmental biologists are teasing apart the genetic
toolbox needed to
assemble animals as disparate as worms and flies, mice and fish. And
paleontologists are
exploring deeper reaches of the fossil record, searching for organisms that
might have primed
the evolutionary pump. "We're getting data," says Harvard University
paleontologist Andrew
Knoll, "almost faster than we can digest it." "
Susan
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For if there is a sin against life, it consists not so much in despairing
of life as in hoping for another and in eluding the implacable grandeur of
this one.
--Albert Camus
http://www.telepath.com/susanb/
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