Cambrian

[NotReady]

I've recently been taking a hard look at Hugh Ross and so far find much of his stuff interesting. Briefly, he's a Ph.D. in astronomy and is also a Christian (y'all would classify him Fundy), and he's been a very prolific writer on science and the Bible, a speaker at many colleges, and has a radio and T.V. show.

He accepts 14 billion and 4.5 billion years as the ages of the universe and earth, but he rejects evolution, taking the position that God has engaged in special creation at various times during the past.

At this point his position appeals to me, and though I'm also comfortable with the possibility of theistic evolution, I don't see any reason to accept it if it isn't true.

So that brings me to the Cambrian explosion. For those who don't know the timeline is something like this (please don't hit me if I get it wrong, I'm just a ignernt layman):

1. 4.5 Bya - earth pops up.
2. 3.9 Bya - single cell life pops up.
3. 550 Mya - all of todays body plans (phyla?) pop up within a space of about 10 My.

Darwin had some trouble with the Cambrian. 3.5 By of nothing, then poof as if by magic, almost everything. I think he basically said that it contradicts his theory, though he expected (hoped?) the fossil record would eventually explain it and thus prove him right.

So my question is this:

Does the Cambrian explosion prove that the fossil record doesn't support Darwinism?

Plese don't cite the Talk.Origins paper on this. I've read it, read the answer to it, and it isn't enough to color me evolutiony.

[Lestat]

Well, I can't give a qualified answer, but I love the subject and will chime in with (what I think) I know.

I'm not sure the Cambrian explosion is the gap from single cell to today's body plans. I thought it was a gap in the actual fossil record itself. If I'm correct...

It's my understanding that we should actually *expect* such a gap. A single fossil is a small miracle in itself. Many things have to happen just right for a fossil to form. The fact is, we are lucky to even have the fossil records that we do.

If the Cambrian explosion is as you describe, it's not hard to imagine how it may have taken considerably longer for life to move ahead from single cells to the next few steps. There's not much to work with from a simple single cell. As a single evolved to a double, then triple and so on, evolution picked up speed.

I wonder if a barren field of dirt might be a good example. It takes a while for a few grass plants to pop up. Then as one becomes two, etc. the whole field quickly fills in.

Or maybe a pot of boiling water. It takes almost forever to bubble. Then one or two, then the whole pot thing is going crazy with energy.

I'm talking out of my ass here, so wait for Borodog or (can't remember the names of the other few very knowledgable posters on evolution). But it makes sense to me that as things multiply, their entire process gathers more speed and energy. I like thinking about this subject, so forgive me for speculating. It's fun for me and I'm making the disclaimer that I'm far from an expert.

Btw- When he takes the position that God engaged in special creation at various times... Does he state on what basis he is staking this position on? And does it have anything to do with science? Or is it just his personal feeling?

[yukoncpa]

The Cambrian explosion that lasted approximately 10 million years brought an abundance of multicellular life.
It did not bring - any plants, any animal groups that we think of today, such as: mammals, reptiles, birds, insects, and spiders. The fish that appeared in the Cambrian were unlike any fish alive today.

It did bring some early transistional animals such as lobopods ( basically worms with legs )which are intermediate between arthropods and worms.

talk origins

[MidGe]

The Cambrian as an issue for evolutionists is a red herring. The last 60 years of field and other research have significantly deepened and changed our view of the Cambrian era. Most of those discoveries have supported evolution as it is known. Indeed, as time as progressed, we have come to know and understand that speciation in the Cambrian, although high, was not so high or distinguishable so, as to warrant formulation of a different speciation mechanism. In other words all evidence that has come to light about this less well known era has supported Evolution Theory. No evidence has been unearthed to suggest the need for a god like interference, tyranical or otherwise.

[Bill Haywood]

No, the Cambrian does not disprove evolution. Yes, it presents some particular problems of interpretation. And if the Cambrian period was the only place we had fossils from, then proof of evolution would be more problematic.

But you have to look at the totality of evidence, and not fixate on the one place that presents problems. That's the fundamental difference in approach between scientists and nuts. Post Cambrian, the evidence of change in form over time is beyond massive.

Why the explosion? Possibly since life was relatively new, the evolutionary forms were more flexible. (Once you are an elephant, it's really hard to become a spider.) And as life became sufficiently populous, the competitive pressures became fiercer, producing the explosion of innovation. Those are top of the head speculations, but as MidGe states, we are a long way from needing supernatural explanations, and the more Cambrian is studied, the more it makes sense in natural terms.

[NotReady]

[ QUOTE ]

then proof of evolution would be more problematic.


[/ QUOTE ]

My question wasn't about proof of evolution. Darwin virtually said the Cambrian disproved his theory, Darwinism. So are you saying Darwin was wrong about himself? Was he a nut?

[chezlaw]

taken from here Seems like a good intro

[ QUOTE ]
Genes or Skeletons?
Charles Darwin (1859, p. 308) recognised that the sudden appearance of a diverse and highly derived fossil fauna in the Cambrian posed a problem for his theory of natural selection, "and may be truly urged as a valid argument against the views here entertained." Two obvious possibilities are that animal life did, indeed, evolve very abruptly about that time, or, alternatively, had existed long before, but that, for whatever reason, we have failed to find fossil evidence: the "late-" and "early-arrival" models, respectively.

The two patterns – Cambrian Explosion versus a very long (though obscure) metazoan history – are not necessarily incompatible, because they are based upon different criteria. The genetic evidence documents lines of descent and inheritance, irrespective of morphology, whereas the fossil record documents only the external expression of the genes.

Late-Arrival Models
The ‘late arrival’ model embodies a literal interpretation of the fossil record: that the evolution of the main animal groups took place both late in Earth’s history, and as we now know, extremely rapidly.

What kind of mechanisms could have prompted such an accelerated pace of evolution? Various proposals have been advanced over the years, including:
A response to the evolution of Hox genes (Erwin et al. 1997).

A rise in macroscopic predation perhaps leading to an ‘arms-race’ style of evolution (Conway Morris 2000). Note, however, that the specific suggestion by Parker (2003) that such an arms race could have been fuelled by the acquisition of high-resolution vision in one or more groups, seems highly implausible (see the review by Conway Morris for a detailed critique).

Finally, perhaps we can look to the lifting of some external constraint such as insufficient atmospheric oxygen (Runnegar 1982; Brasier 1998, p. 548; Adouette et al. 2000, p. 4455).

Nowhere is the late-arrival model more eloquently discussed than in Stephen Gould’s Wonderful Life (Gould 1989), though nearly everyone would now agree that, in this book, Gould overstated his case by some orders of magnitude.
(Read more.)

Early-Arrival Models
Darwin himself preferred the early-arrival explanation, noting that "before the lowest Silurian [the Cambrian system had not yet been recognised] stratum was deposited, long periods elapsed, as long as, or probably far longer than, the whole interval from the Silurian age to the present day; and that during these vast, yet quite unknown, periods of time, the world swarmed with living creatures" (Darwin 1859, p. 307).

Today we might regard Darwin’s views as wonderfully prescient, for numerous Precambrian fossils have now indeed been collected, and modern techniques – impossible in Darwin’s day – such as ‘molecular clock’ studies, strongly indicate metazoan evolutionary events having occurred deep within the Precambrian.
There can be little doubt, on the basis of trace evidence alone, that bilaterian metazoans existed in the Vendian, and possibly early in the Vendian. Although some traces are simple, rather featureless, winding trails, "others display transverse rugae and contain pellets that can be interpreted as of fecal origin. The bilaterian nature of these traces is not in dispute. Furthermore, such traces must have been made by worms, some of which had lengths measured in centimetres, with through guts, which were capable of displacing sediment during some form of peristaltic locomotion, implying a system of body wall muscles antagonized by a hydrostatic skeleton. Such worms are more complex than flatworms, which cannot create such trails and do not leave fecal strings" (Valentine 1995, p. 90).
"The lack of any evidence of horizontal burrowing in rocks older than about 575 Mya and of vertical burrowing in rocks older than 543 Mya is a strong argument that there existed no animals about 1 cm or longer that were capable of disturbing sedimentary layers before this time. When they do appear, these bilaterian traces indicate the presence of animals that had AP [anterior-posterior] differentiation, but there is no evidence of limbs" (Erwin & Davidson 2002, p. 3023, but note these authors were apparently unaware of Arenicolites).
Sets of paired hypichnial ridges strongly hint at an arthropod s.l. presence. [Where and when? Reference?]
An entirely independent line of study is reported in Lieberman 2003. Here, the results of a phylogenetic biogeographic analysis of Early Cambrian olenellid trilobites are calibrated by a tectonic event, the breakup of Pannotia at 600 to 550 Ma, providing evidence that "trilobites likely had evolved and begun to diversify minimally by between 550 to 600 Ma" (Lieberman 2003, p. 231).

In preserving evidence of bilaterians, the Vendian record provides constraints on the protostome-deuterostome (P-D) divergence. If Kimberella is indeed a mollusc, as suggested by Fedonkin & Waggoner 1997, or certain trace fossils recorded from the Ediacara Hills and Zimnie Gory are correctly interpreted as radula scratches, we have evidence for derived protostomes at 555 Ma. Similarly, if Arkarua adami (from the Pound Subgroup, South Australia; Gehling 1987) is correctly interpreted as an echinoderm, we have evidence for a derived deuterostome of similar age. In either case, it follows that the protostome-deuterostome split must have occurred well before 555 Ma, which is consistent with most ‘molecular clock’ studies.
The latter, however, mostly favour a P-D split far deeper in the Precambrian: some as early as 1,200 Ma (table 1). If correct, then the Cambrian explosion is clearly an artefact.


[/ QUOTE ]

chez

[niffe9]

Darwin said nothing of the sort that this evidence disproved his theory. He said that the evidence did not fit the set of principles of evolution.
Even if the cambrian explosion is shown to clearly be contradictory to the theory of evolution (which is not true, as someone has stated before, because in the last 20 years efforts in that specific field have supported evolution), evolution is still far and away the best explanation for how humans got here. Molecular genetics and geographical distribution are two areas that overwhelmingly support evolution by themselves. Just because evolution has flaws does not mean in any way that creationism is correct.
Once again, it is good that we are critical of theories and the evidence that supports it. This is science. However, to say that evolution is not the best explanation for how humans came to be is a HUGE claim.

[Phil153]

[ QUOTE ]
Charles Darwin (1859, p. 308) recognised that the sudden appearance of a diverse and highly derived fossil fauna in the Cambrian posed a problem for his theory of natural selection, "and may be truly urged as a valid argument against the views here entertained."

[/ QUOTE ]
This is the reason why science will always be >>>>>> closed minded people like NotReady

[NotReady]

[ QUOTE ]

Darwin said nothing of the sort that this evidence disproved his theory. He said that the evidence did not fit the set of principles of evolution.


[/ QUOTE ]

You don't see a contradiction in these two statements?

1. The evidence doesn't fit my theory.
2. My theory isn't disproved.

[ QUOTE ]

Just because evolution has flaws does not mean in any way that creationism is correct.


[/ QUOTE ]

I didn't say anything about evolution. I asked about Darwinism and the fossil record. And creationism and evolution are not mutually exclusive.

[ QUOTE ]

However, to say that evolution is not the best explanation for how humans came to be is a HUGE claim


[/ QUOTE ]

It may or may not be an explanation. But if Darwinism isn't supported by the fossil record I don't see how evolution can be anything but a partial explanation.