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Originally posted by Quetzal:
Hi Bart:
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Isn't evolution suppose to flow the other way. You do not start out with phyla that evolve all creatures according to their phylum, that sounds a bit creationist. Evolution demands it start out with a single self-replicating somehing or other, that speciates over and over into many new species, which evolve into new genesus, which evolve into new groupings known as families, etc., etc., all the way up to new phyla.
Not really. This is a relatively common misunderstanding of linnean classification and "phyla" in particular. A critter is assigned to a phylum based on a shared body plan. All phyla were described within the last couple hundred years - using modern organisms. One of the key fallacies here is that means that all extinct organisms - whether they really share a body plan or not - are shoehorned into one of the 33 identified phyla alive today! Needless to say, this means that some of the really weird pre-Cambrian and Cambrian fossils are listed in one of the modern phyla - whether they share a common body plan or not - leading to serious misconceptions that all phyla magically appeared 580 million years ago. In point of fact, only about 13 actually show up in the fossil record during the Vendian and around the Paleozoic-Cambrian boundary (the so-called "explosion"). Here's a listing:
Era Phyla
Recent 13
Eocene 2
Cretaceous 2
Jurassic 1
Triassic 3
Carboniferous 5
Devonian 4
Silurian 1
Ordovician 1
Cambrian 9
Vendian 4
As you can see, only 13 phyla show up during/prior to the Cambrian. 20 phyla appear later. There IS, therefore, evidence of inter-phyla evolution. Why? Because "phylum" is simply a convenient term, not an intrinsic entity defining a discontinuity or barrier. Even then, stuffing organisms into existing phyla leads to problems: look up Asbestopluma or the Cladorhizidae - classified under phylum Porifera, but sharing none (or almost none) of the Porifera bodyplans. The whole thing is very arbitrary - and substantially more complex than a cursory examination of the issue would lead one to believe.
You are correct that Linnean classification provided the 33 or so Phyla based upon observation of the different basic bauplanes (i.e. body planes) of extant animals.
Unfortunately, you abandon science to pursue the special pleading type arguments of a dogmatic evolutionists who are also rabid anti-creationists.
I see you seek to persuade me with the great works of Glenn R. Morton, a dogmatic evolutionist and anti-creationists. Where does he get his information on Phyla? He says it is from Berkeley University.
Glen writes: "Berkeley has posted an interesting display of when the various phyla appear. It can be found at
First Appearances of Metazoans"
But when we go to that web page, we discover it is not an official document from Berkeley, rather, it is a web page of a student attending Berkeley, Ben Waggoner. Even so, Glenn misrepresents Ben's web page, for Ben writes of his own chart:
"The chart above shows the oldest undoubted fossil occurences of each of the living major groups of animals. Note how many of the animal groups have fossil records that date back to the Cambrian period, over 500 million years ago. Those groups which do not date back to the Cambrian, with the single exception of the Bryozoa, do not possess mineralized skeletons. It is likely that all major animal groups, even those which have not left us fossils, originated in the Cambrian. This sudden appearance of many major groups of animals is often referred to as the "Cambrian Explosion"."
BTW, Glenn readily admits that the experts, the scientists who have obtained, examined, discussed and published in their peer reviewed journals, the scientific data of on Cambrian Phyla, that 32 of 33 Linnean classifications of Phyla of extant metazoans are found in the Cambrian explosion. He amazingly chooses to ignore them and even his primary source, Ben Waggoner, who ultimately agrees with the Paleontologists.
There have been estimates of up to 84 Phyla that appear in the Vendian/Cambrian period. Many have become extinct. Since the Cambrian era, not one new bauplane (i.e. Phyla) has arose.
It is not I who misunderstands. In fact, I understand all too well. YSome evolutionists prefer the special pleadings of a dogmatic evolutionists like Glenn Morton, who happened to be engaged in a crusade against creationists, over accepting the actual scientific findings.
Here is an article posted by PBS on their evolution web site. They are squarely in the evolutionist camp with their strong bias in favor of Evolutionism. They speak of the Cambrian Explosion:
"530 mya: The Cambrian explosion
"The basic body plans of the major animal phyla are established over a relatively short period of roughly 10 million years. All the major animal phyla that exist today -- about three dozen -- evolve from these Cambrian faunas.
"The Cambrian explosion (530-520 mya)
"While scientists now know that animal life existed prior to the Cambrian explosion, the diversity of life that evolves during its 10 million years remains significant. While the soft-bodied Ediacaran animals had no protective coverings, many Cambrian animals evolved skeletons, such as shells or other brittle coatings. Among the more familiar groups to appear include sponges, brachiopods (lamp shells), spiny-skinned echinoderms, early gastropods (snails), cone-shelled cephalopods, and primitive arthropods called trilobites. Several other creatures that are unrelated to any currently living form also appear, but they die off after a short time.
"A combination of environmental factors probably contributes to this evolutionary burst. Oxygen, which is plentiful in both the atmosphere and in the oceans, allows physically larger animals to evolve. Warm, free-flowing ocean currents probably carry these animals to new marine niches, where they adapt to new settings and evolve different characteristics.
"Environmental factors alone, however, cannot explain why major animal phyla have not evolved in the 500 million years or so since the Cambrian explosion. Studies comparing fossilized embryos and a wide range of contemporary specimens suggest that homeobox genes -- genes that control whether certain cells specialize to form muscles, nerves, or glands, for example -- are remarkably similar in all species. The mutations that give rise to these control genes may be advantageous only in the earliest, simplest animals."
Evolution: Change: Deep Time
Postscript.
It is ludicrous that PBS writes loaded sentences to browbeat unwary readers into accepting the materialistic evolutionary worldview. Here is such a typical browbeating statement by PBS: "The mutations that give rise to these control genes...". Neither PBS nor Science know anything about any mutations giving rise to control genes. PBS can only justify such a statement because they "KNOW" evolution is a "FACT". This is teaching (of science) at its' worse.
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