Speculation and even heated debate have attended the study
of earth's history. The Cambrian/Pre-Cambrian event is no exception.
fossils are rare and seldom well preserved.
The boundary between Pre-Cambrian and Cambrian strata
is often, but not always, clearly defined. In the rare instances where
it is not clearly defined, one investigator's opinion may differ from
another's regarding its exact position.
It seems reasonable to make the following generalisations:-
- The event of which the Pre-Cambrian/Cambrian Unconformity bears record
was world-changing and occurred between five and six hundred million
- The most complex fossils currently assigned to the Pre-Cambrian include
internally semi-symmetrical structures no larger than a pencil dot,
and enigmatic slug and jellyfish-like remains.
- There is no proof of Pre-Cambrian life more complex than that of plants.
Organisms such as those illustrated here have not been shown to be anything
more than 'organised seaweed'.
- Truly complex -- that is, animal-grade-life -- first leaves a record
in the Cambrian. Every division of complex life, including the vertebrates,
is represented in Cambrian strata. In the case of the vertebrates, these
earliest representatives were embryonic and almost unrecognisable as
vertebrates. In other divisions of life, such as the sea insects and
various sea shells, the Cambrian representatives were, in some cases,
- Not long before the termination of the Pre-Cambrian there was a significant
increase in the complexity of some living organisms.
The engine behind the breaking forth of complex, animal-grade life during
the earliest Cambrian is investigated elsewhere on this
site. This leaves another intriguing question. Why did the (simple,
plant-grade) life of the Pre-Cambrian begin to increase in complexity
before the main Pre-Cambrian/Cambrian Event?
If a major planetary event, such as that suggested for the explosion
of complex life, was a factor in the information signalling requisite
to the creation and revelation of complex species, could a lesser planetary
event have played a part in the advance of plant-grade life immediately
prior to the main Event?
It is here suggested that capture, by the earth, of various ice-bodies
contributed to increased quantum electro-magnetic signalling at that time.
These ice-bodies may also have served as cushions in the moon introduction
event and as a standing source of supply for the earth's atmosphere as
the newly created organisms drew on its supply of essential elements such
Duke University (2008, December 4). Rolling 'Sea Grape'
Rocks The Fossil Record. ScienceDaily. Retrieved January 3, 2009, from
University of Leicester (2008, February 22). Ancient
Puzzle Solved In Fossils From Canadian Rockies, Dating To Cambrian Explosion.
ScienceDaily. Retrieved January 3, 2009, from http://www.sciencedaily.com/releases/2008/02/080219095801.htm
University of Texas at Austin (2008, November 21).
Discovery Of Giant Roaming Deep Sea Protist Provides New Perspective
On Animal Evolution. ScienceDaily. Retrieved January 3, 2009, from http://www.sciencedaily.com/releases/2008/11/081120130531.htm
Bottjer, D.J. 2005, 'The Early Evolution of Animals',
Scientific American, Aug. 2005, Vol. 293, No. 2, pp. 30-35.
Reader, J. 1986, The Rise of Life, William Collins
& Sons, London. Illustrations by John Gurche.