Brin asked in Science & MathematicsBiology · 1 decade ago

What was the Cambrian Explosian and how does it confirm/discredit evolution?

Does anyone have information on the cambrian explosion? I want to know if it has changed anyones view of the theory of evolution. Please cite sources if you have facts to share. thanks.

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    1 decade ago
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  • 1 decade ago

    The Cambrian explosion was actually a diversification of many new body plans into a permissive (low competition) ecology, that lasted 50 million years (a rather slow, drawn-out "explosion"). It is a perfect example of how evolution works. The Earth was dominated by simple single celled species for more than 2 billion years before a series of extreme global cooling and warming cycles 1,100,000,000 to 670,000,000 years ago caused mass extinction and thus created the ecological opportunity for many new forms to evolve. Many of these forms we find in the Cambrian, 550-500 million years ago when the evolution of calcified body parts made fossilization more probable, but earlier transitional forms from as far back as 660 million years ago, shortly after the last "iceball Earth" period reveals that the diversification with multicellular soft forms actually started during that earlier preCambrian time.

    Source(s): for information on preCambrian transitional forms google recent paleontological findings on the Doushantuo formation in China (as many as 80 forms transitional to Cambrian species have recently been uncovered) for information on "iceball Earth" cycles google Paul Hoffman (Harvard U)
  • 1 decade ago

    It is a specific time period in which many fossils have been found for many different species. There is not a lot of fossils found right before this, so the evolutionary "map" (if you will) is very incomplete as to the relations of these species prior to the period. It really isn't a problem with evolution. Basically the time period right before it has a lot of unanswered questions, which means a lot of the Cambrian Explosion also has unanswered questions. But there is nothing about it that would discredit evolution. Creationists use it as circumstantial evidence as to a large number of species being "created" all at once. But there it no actual evidence of this.

    There is also some debate about the speed in which the new species appeared. There appears to be a massive increase in the number of species during this time. And some argue that evolution couldn't work this fast. But lack of a complete fossil record and primitive knowledge as to the environment make this a weak argument.

  • 1 decade ago

    The Cambrian Explosion (IMO a name as bad as the "Big Bang") refers to a dramatic increase in the number of different species that appears in the fossil record about 580 million years ago (the beginning of the Cambrian). It is dramatic in the sense that after several *billion* years of relatively slow, stable evolution of very simple organisms, in the space of "only" 70-80 million years, the rate of production and complexity of new species found in the fossil record "exploded" by an order of magnitude.

    NO serious scientist believes that the Cambrian Explosion does anything at all to discredit evolution.

    Here's why ...

    1 - It is fully consistent with the evidence of evolution both before and after that time period ... it is a change only in the *rate* of that evolution ... the rate at which diversity increased.

    2 - It is universally accepted by scientists to have occurred about 580 million years ago. People who claim that this is evidence of a creation that happened only 6,000 years ago are taking a scientific fact (the change in the fossil record) and twisting it to absurdity.

    3- It is "sudden" in the geologic sense only ... lasting "only" 70 to 80 million years. But it is not "sudden" in any human sense of the word. Even the word "explosion" is purely figurative (the way we might say "there was an explosion of new ideas during the Renaissance").

    4 - It is also "sudden" in the sense that it occurred at a rate faster than the fossilization. In other words, transitional forms came and went faster than the fossil record could record all of them. Any discontinuity in the fossil record is only that ... a discontinuity in the *record* not in the process (evolution).

    5- There are many perfectly plausible explanations for the event ... all of which are perfectly consistent with evolution. These include a mass extinction just before the event, population bottlenecks, expansion of vast new ecological niches, a change in atmospheric conditions, some new developments in sexual reproduction, changes in the hardness of bodies thus producing more fossils, or various combinations of these ... NONE of which contradict evolution. Creationists who claim that scientists "have no explanation" for the Cambrian explosion, are either quite out-of-touch with science, or are flat-out lying.

    { edit }

    skot302002 is a case in point. He apparently did not read my point #4. The Cambrian record is not "devoid" of transitional fossils ... they are there ... it is only that the rate of diversification was actually faster than the ability for fossils to record every single transition. For skot to generalize this to say that this is a problem in "all fossil finds", shows that he has bought into the creationist lack of familiarity with the fossil record ... or the lie-repeated-like-a-mantra that "there are no transitional fossils." Either way ... total nonsense.

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  • The Cambrian Explosion occurred when Cambridge University in England exploded due to a break in a gas line. It has nothing to do whatsoever with evolution, except to prove that stupid maintenance workers don't live long enough to reproduce!

  • 1 decade ago

    Creationists use the term 'Explosion' to sow confusion. When we think explosion, we think fast in the scope of our lifetimes, which means seconds. Biologists know new forms don't appear that quickly. But on a geological scale, we're talking about events which happened over hundreds of thousands or millions of years. This is, in a sense, an explosion, because it is a small amount of time when you consider the age of our planet and the age of the universe.

  • 1 decade ago

    No one addressed one important fact about the Cambrian Period : like all other fossil finds, it is completely devoid of any "transitional" specimens just like every other discovery. There is no more scientific evidence or fossil record that validates evolution than there is creationism. Both are faith based.

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