The Cambrian as an evolutionary exemplar

The kings of creation at this time were scattered beasties the size of a baby's toenail, but still, it was a step upward in size and durability from what had come before.

Proterozoic modular biomineralized metazoan from the Nama Group, Namibia. Wood RA, Grotzinger JP, Dickson JA. Science. 2002 Jun 28;296(5577):2383-6. We describe a Proterozoic, fully biomineralized metazoan from the Omkyk Member (approximately 549 million years before the present) of the northern Nama Group, Namibia. Namapoikia rietoogensis gen. et sp. nov. is up to 1 meter in diameter and bears a complex and robust biomineralized skeleton; it probably represents a cnidarian or poriferan. Namapoikia encrusts perpendicular to the walls of vertical synsedimentary fissures in microbial reefs. This finding implies that large, modular metazoans with biologically controlled mineralization appeared some 15 million years earlier than previously documented. Pubmed

Excellent posting. Why ID creationists are still using Valentine's earlier work and ignore his book is somewhat puzzling to me.

up to 1 meter in diameter

— Pete Dunkelberg

There is something deceitful about most the nonsense written on the Cambrian Explosion, as YECs simply deny geological time and IDiots just ignore it. The explosion took one hell of a long time!

This confirms to me that the most improtant scientific argument to get across is the vast age of the earth and the universe. Evolution should always take second place - I will get my knuckles wrapped for this! When dealing with YECs I seek to convince them that the earth is old - a few million will do. You have then destroyed all the main theolgical planks of YEC and evolution might come later

PS I mapped a few thousand sq miles of late Precambrian in the Richtersveld, just inside South Africa years ago, which was older than the Nama and included the Numees tillite in which I found a stromatolite in associated dolomite, and also a dropstone and varves. I still wonder if I walked over some nice fossils which I didnt see because I wasnt looking. I lived for six months at Numees in a caravan while assessing the viability of the Numees copper mine,

Indeed it did. The scenario for IDers is as follows:

God sits around. Hmmm, he thinks, I'm a bit bored today, what shall I do? I know, lets magically poof Wiwaxia into existence. That was fun, now I think I'll sit around for a few hundred thousand years. Dum de dum (twiddles thumbs), la de da. By eck thinks God (God is a Yorkshireman you see), I haven't done any creating for a while, I think its time to create Lingulella. Phew, I'm tired now; time for another break. Etc etc.

Or you could be a YECist IDer (and I bet there aren't too many of them around. Perish the thought) and argue that the Cambrian explosion is a major problem for evolution. Of course if you were to do this you would be being thoroughly dishonest because you don't think the Cambrian explosion has anything to do with the development of life on earth. Its simply something to do with a flood.

I was looking at Pharyngula and found this ;

Atheist Revolution: Religious belief is a destructive force that causes far more harm than good. Atheist Revolution is a blog dedicated to breaking free from irrational belief and opposing Christian extremism in America.

Now what IS interesting is the beleifs of Adam Sedgwick who first sorted out the Cambrian in the days after Darwin left him on 21st August 1831 somewhere around Bangor. He was an Evangelical Christian and an ordained cleric in the Church of England. He also wasnt very good at fossils but identified quite a few. I have retraced many of the routes he did in North wales in 1831 (as I did all Darwins) and his longest route was 18 miles in the mountains (Carneddau) with over 6000ft of climbing. It took me over 10hours walking flat-out with my dog.

Now was Sedgwick irrational or not?

> God sits around. Hmmm, he thinks, I'm a bit bored today, what shall I do? I know, lets magically poof Wiwaxia into existence. That was fun, now I think I'll sit around for a few hundred thousand years. Dum de dum (twiddles thumbs), la de da. By eck thinks God (God is a Yorkshireman you see), I haven't done any creating for a while, I think its time to create Lingulella. Phew, I'm tired now; time for another break. Etc etc.

And according to Behe, God created insects and then waited millenia before creating plants -- I guess he got annoyed by the hungry clacking of their empty mouthparts.

At the era of the Cambrian, are there any estimates as to the average livespan of these creatures? A few years on the long side, or way shorter? It seems to me, with no data whatsoever, so I'd be better off speculating my entire equity on DrKoop.com than saying this, but might the "cambrian explosion" be a reaction to a rapid ecological change? Or response to?

I was thinking in regards to chaos theory where a periodic occilation, but not quite exactly periodic, suddenly shifts, the example being heart arythmia. Thus, a very long stable period of conditions suddenly yields to a change that puts pressure on species present.

And, finally, are there other "explosions" or little bangs, even, in response to similar changes?

YEC: There was no Cambrian.
IDC: God was more active in the Cambrian than at other times including the present.

Re "but might the "cambrian explosion" be a reaction to a rapid ecological change? Or response to?"

Something I read not too long ago (might have been on this blog or TalkOrigins archive) suggested that the "explosion" might have followed from some species developing vision, and thus finding its prey quicker than everybody else. So everybody else suddenly had to either catch (develop defenses of some sort) up or go bye bye. Sounds plausible.

Henry

Andrew Parker's "In the Blink of an Eye" makes that argument. I read it some time ago and wasn't much impressed. I'd give the Amazon URL, but I haven't figured out the latest incarnation of KwickWhatsit tags.

Just type the URL, e.g., http://www.amazon.com
Or you can get fancy (the quotes are necessary): click here for the amazon link
click here for the amazon link

Actually you can be fancier:

click here for the amazon link

Where "ASIN" is the ASIN of the book you want. It even inserts the TOAF referer code.

In the Blink of an Eye

In the Blink of an Eye

So can we have a link to page describing the syntax? :-)

Why ID creationists are still using Valentine's earlier work and ignore his book is somewhat puzzling to me.

Andrew Parker's "In the Blink of an Eye" makes that argument. I read it some time ago and wasn't much impressed.

PvM wrote: "Excellent posting. Why ID creationists are still using Valentine's earlier work and ignore his book is somewhat puzzling to me."

Are you also "puzzled" why they frequently cite Michael Denton's 1985 book "Evolution, a Theory in Crisis," yet almost always ignore his 1998 book "Nature's Destiny"?

Ah. Then the hypothesis (of development of visual sense as driver) isn't widely accepted. Then again, wouldn't have to be vision - seems like anything that improves hunting ability (or evading ability) in one species would put pressure on the others to develop something to counter it. Seems like that could produce the sort of positive feedback loop that seems to be involved.

I wonder if an increase in the oxygen level might have had something to do with it. (Or more generally, increase availability of any important resource.)

Henry

Ah. Then the hypothesis (of development of visual sense as driver) isn't widely accepted. Then again, wouldn't have to be vision - seems like anything that improves hunting ability (or evading ability) in one species would put pressure on the others to develop something to counter it. Seems like that could produce the sort of positive feedback loop that seems to be involved. I wonder if an increase in the oxygen level might have had something to do with it. (Or more generally, increase availability of any important resource.) Henry

Re "but what improves hunting (or evading) ability like vision?"

Well, I don't know that other developments would be like vision specifically, but I can think of a bunch of things that would increase efficiency or effectiveness - armor, claws, teeth, running (or swimming) faster, improvement in other senses (hearing, smelling), poison injection, camouflage (against others that have vision), something to act as bait. Or any combination of those.

Henry

This leads to an interesting question - are there animals who use non-visual camouflage? For example, moths camouflaged against bat's sonar?

I just happened to read passage in Grimaldi and Engel's new book Evolution of the Insects that deals with something like non-visual camouflage.

Tiger moths have sound producing organs whose output may serve to jam bat sonar. But these moths are toxic because of the plant chemical ingested by their larva so the high-frequency sounds they emit may actually be more analogous to the bright colors of poisonous butterflies and stinging wasps, a way of warning off predators.

By the way, the Grimaldi and Engel book is absolutely splendid.