Wall-dog wrote:
The Cambrian pictures are a parlor game. BeGood has already agreed with Dr. Wells that animals within a given phyla have more in common with each other than they do with animals in other phyla.
Again you don't understand the meaning of Phylum. The reason that all chordata belong in the same phylum is because they posess a notochord, and later spinal chord. The image I provided is a representative of this group.
Wall-dog wrote:Showing a picture of two vastly different creatures to show that they look very little like later creatures does not explain how those creatures came about. You go from single-cell organisms and sponges to all phyla in a span of no more than 10 million years.
No worms, sponges and jellyfish existed pre-cambrian.
Wall-dog wrote:Some Chinese scientists (where many of the fossils are coming from) are saying it was only 5 million years.
Have you looked at the evidence?
Wall-dog wrote:Look at what BeGood has already posted. He shows an incredibly complicated creature complete with intestine, esophagus, epidermal, cuticle, and a cerebral ganglia (primitive brain).
All present in worms.
Wall-dog wrote:He could also have put up pictures of creatures with eyes and skeletons but for obvious reasons he wants to use the simplist-looking organisms he can find.
Now your being misleading There are no organisms which posses skeletons in this period.
Wall-dog wrote:Remember that these creatures shows up in the blink of an eye with no ancestors.
You know this for sure?
Wall-dog wrote:Evolution has no explanation for them. All BeGood can do is say 'hey - they don't look like crocododiles so they must have evolved!' In truth, the phyla the crocodile is in has far more in common with the crocodile than it has in common with any of the other phyla from the period.
I think it's clear that the primitave chordata has far more in common with a worm dthan it does with a crocodile.
Wall-dog wrote:So my 'BAM there's a crocodile!' analogy stands exactly as before. It's exagerated for emphasis but the premise is absolutely true. So we go from single cell organisms to advanced and incredibly complex life in 5 to 10 million years. You want more pictures? What I'd like BeGood to post is how fast evolution has to get before he's willing to give it a speeding ticket.
See your sticking to that mental picture without even examining the evidence.
Wall-dog wrote:Here is the thing. For the theory of evolution to hold the model has to work using unguided principals. Once you throw that out suddenly all of the other breaks in the fossil record are up for grabs too. And every fossil is an island. There are no chains - only islands. Evolution looses it's empirical backbone on the Cambrian explosion. While we know it occurs at some level we can no longer assume that it occurs any further than we can actually account for because we also know that it does NOT occur at all levels!
Again you misunderstand the classification scheme, the levels appear because through time diversification occurs at the only level possible, populations.
Here's an analogy, two twins begin in the same spot at age twelve. They decide to walk in opposite directions one east and one west, after about one week their set of experiences has diverged, we will call this species level diversification. After a month their shared experiences are even greater, lets call this genus level difersification. After 30 years they have a great deal of disparate experiences, this we'll classify as order level diversification. After 60 years they have completely different experiences, this is phylum level.
Now to fill it in lets say that at each point in time in the above example each twin split in two. The two branches of twins, one heading east and one heading west represent two phyla.
Wall-dog wrote:To pull out a succinct part of that long Wells quote:
According to Darwin's theory of evolution, all animals are descended from a common ancestor in the distant past. Supposedly, a single primitive species gradually diverged into two species, then those diverged over millions of generations to the point where we now see the major differences in body plans among worms, clams, crabs, starfish and vertebrates. Yet when we look at the fossil record we see that most of these major differences were present at the earliest appearance of animal life. Darwin himself knew this, and in The Origin of Species he called it a “serious” problem for his theory.
But what are the major diferences we are talking about?
Here are the phyla present in the cambrian.
Porifera - sponges
Annelida - segmented worms
Cnidara - nematocysts (stinging harpoon like cells)
Mollusca - mantle
Echinodermata
Arthopoda - exoskeleton
Nematoda - The first Nematode fossil is found in the Cenzoic
PlatyHelminths - Absent in the fossil record
Bryozoa
The first list has representitives in the Vendian Period
The second list contains some phylum which have not been found before the ordavicion.
In all there are 30 modern phylums some 9 of which appear in the Cambrian for sure and several more which probably originate in the cambrian. And along with this there are several perhaps 5 or more extinct phylums originating in the Cambrian.
Wall-dog wrote:The geologically abrupt and simultaneous appearance of most of the major groups of animals is now known as the “Cambrian explosion,” after the name of the geological period in which they first appear. Darwin thought that the Cambrian explosion might simply be an illusion caused by flaws in the fossil record, but a hundred and forty years of additional fossil collecting have dispelled this notion. Paleontologists James Valentine and Douglas Erwin wrote in 1987 that the Cambrian explosion “is real; it is too big to be masked by flaws in the fossil record.” And in 1991, Valentine and his colleagues wrote that the Cambrian explosion “was even more abrupt and extensive than previously envisioned.” (In Raff & Raff, eds., Development as an Evolutionary Process, Liss, 1987, pp. 84-85; and Evolutionary Biology 25, 1991, pp. 279-281)
I wonder how out of date this is?
Wall-dog wrote:What BeGood either fails to understand or (more probably) just isn't willing to admit is that this statement, which he made, proves the point:
But for the record I did not want to imply that all the forms were similar, only that the words first appearance of a particular phylum produce a far different mental picture than the actual evidence.
You misunderstand me, I am not saying all cambrian forms are similar, but you are overstating the differences greatly. All I am asking is for you to look at the evidence yourself.
Well lets take a look at the evidence and look at what the latest ideas are.
Annelida are a group of animals, the segmented worms, which appeared in the vendian precambrian.
It is beleived that the first arthopods, and brachiopods came from this lineage.
Arthopods - later to be insects, spiders, crabs etc..
And there are precambrian arthopods.
This one appears very similar to trilobites in the cambrian.
Here is a transition form between a segmented worm and an arthopod.
Which one is it?
Now for Brachiopods.
From here Moluscs are thought to have come from brachiopods.
We could spend all day on this so I will reserve more if there are further inquiries.
Wall-dog wrote:The 'mental picture' isn't relevant. What is relevant is that evolution cannot account for those organisms. Folding proteins and the notion that a single cell found a new piece of ocean and said "Hey! This isn't populated yet. BAM I'm a really advanced organism now!" well - that just doesn't work. I mean when you really think about it, it just doesn't work.
Primative sponges are basically a colony of single cells working together. No-one said Bam! That is again your mental image of it.
Wall-dog wrote:Who cares what those incredibly complex creatures looked like? They sure didn't look like anything that came before them.
New discoveries have confirmed the link between arthopods and annelids are you sure we won't find more?
Wall-dog wrote:And since evolution DEFINITELY cannot explain the phylum, why should we believe without empirical proof that it occurred at other levels?
A manipulation of ideas. There really are no levels. Its an abstract concept.
In any case do these organisms bear any resembelance to modern forms?
They don't do they.
Lets take away the idea of evolution all together.
All you have left is a collection of wormy bug like things. On what basis can you claim that there is an explosion? Only in the context of evolution and classification is there an explosion of forms.