What does “without any obvious precursors “ mean to you?
Do you think I meant “no life existed before the Cambrian”?
I didn’t say that at all! What a strawman.
Stromatolites are not obvious precursors of the Cambrian fauna.
If I recall, you presented the same strawman in the past!
It doesn't seem you actually know what you are arguing for. If you agree that life existed before the Cambrian, then what's the big problem? Are you assuming that all existing animal phyla we see today were "created" by your god during this period? That wouldn't be accurate either.
"Let us begin by talking briefly about the pre-Cambrian. Creationists who deal with the “sudden appearance” argument like to leave students with the impression that the Cambrian explosion actually provides fossil evidence for the Creation as described in the books of
Genesis. They will therefore conveniently neglect to present the clear fossil evidence that life extends back to at least 3.5 billion years before the present. To address this misconception, teachers should show students some of the many images of pre-Cambrian microfossils that are available on the web. The University of California Museum of Paleontology—
http://www.ucmp.berkeley.edu—is a good place to start. Other good sites include:
www.pnas.org/content/97/13/6947.figures-only and
Request Rejected. Teachers should make it clear that these pre-Cambrian microfossils account for the majority of the history of life (about 80% of it in fact). If inclined to be philosophical, teachers might also raise a question here about why it took such a long time (i.e., just under three billion years) to evolve the earliest animals. Why were nearly three billion years required before single-celled creatures could give rise to the first animals?
The second point to make about the pre-Cambrian fossil record is that there are already a number of animal fossils present in rocks of late pre-Cambrian age—now often designated as the Ediacaran period. Although the precise phyletic affinities of these fossils are not fully resolved, there are clearly sponges, radial animals, and some bilateral forms present. Furthermore, there is additional evidence from molecular clock studies and paleobiogeography that many of the taxa that first appear as distinct fossils in the Cambrian have roots that extend well back (tens of millions of years back) into the pre-Cambrian (Knoll and Carroll
1999; Lieberman
2003). This should also be a central point that teachers make.
In other words, the Cambrian explosion does not document the “sudden appearance” of all animal phyla. A significant number of animal phyla are already present prior to the explosion. It is simply that we remain unsure of their exact classification precisely because they are so different from living animals. To illustrate this, a page within the Berkeley museum site provides a series of excellent pictures and descriptions of these pre-Cambrian animal fossils (
Vendian Animals).
Recent action taken by the Texas State Board of Education has opened the door to the inclusion of creationist arguments into public school science curriculum in that state and—because of the critical role of Texas in textbook adoptions—perhaps in many other states as well. One of the arguments...
evolution-outreach.biomedcentral.com
"Most scientists are persuaded that something significant happened at the dawn of the Cambrian era and view the Cambrian Explosion as an area of exciting and productive research. For example, scientists are now gaining a better understanding of what existed before the Cambrian Explosion as a result of new fossil discoveries. Recent discoveries are filling in the fossil record for the Precambrian fauna with soft-bodied organisms like those in the Ediacaran Assemblages found around the world.7 Late Precambrian fossil discoveries also now include representatives of sponges, cnidarians (the group that includes modern jellyfish, corals and anemones), mollusks and various wormlike groups.
Some of the new fossil discoveries, in fact, appear to be more primitive precursors of the later Cambrian body plans.
The discovery of such precursors shows that the Cambrian organisms did not appear from thin air.8 Further discoveries will no doubt reveal more clearly the relationship of Precambrian organisms with the creatures found in the Burgess Shale and Chengjiang deposits.9
The Cambrian Explosion does present a number of important questions, but it doesn't challenge the fundamental correctness of the central thesis of evolution.
biologos.org
pubmed.ncbi.nlm.nih.gov
www.forbes.com
