More than half a billion years ago most of the major animal groups appeared abruptly in what is known as the Cambrian Explosion. It initiated virtually all the major designs of multicellular life with barely a trace of evolutionary history. In a geological moment, the fossil species went from small worm-like creatures and the like to a tremendous diversity of complex life forms.Evolutionists have had little success explaining this onetime event. Thomas H. Huxley likened it to a barrel that is filled rapidly with apples. Then it takes longer to fill the remaining spaces with pebbles, sand and finally water. Today’s explanations are more technical-sounding but no less reliant on speculation as opposed to direct description. Steven Stanley compared it to the introduction of bacteria croppers which prey on dominant species which previously had suppressed diversity. J. J. Sepkoski compared it to rapid growth of bacterial populations in a virgin petry dish. Were the Precambrian oceans a virgin ecosystem with the raw materials of oxygen and food supplied by ancient bacteria? Steve Jones wondered if the Cambrian explosion reflects some crucial change in DNA—life’s genetic material. "Might a great burst of genetic creativity," asks Jones, "have driven a Cambrian Genesis and given birth to the modern world?"
Now, thanks to new research, we have yet another explanation: calcium. Evolutionists are now saying that a rise in ocean calcium levels may have triggered the assembly of unicellular organisms into multicellular organisms and the rest, as evolutionists say, is history. As one report explained:
the question of what was the trigger for the single cell microorganisms to assemble and organize into multicellular organisms has remained unanswered until now.
What is astonishing is that there is anyone left out there who questions evolution. Can't they see that these guys are doing the heavy lifting? This is just rock solid investigative research, the kind we've come to expect from evolutionists.
It initiated virtually all the designs of multicellular life with barely a trace of evolutionary history
ReplyDeleteSo, in the ID academy, plants are not multicellular life. Methinks someone's been reading a bit too much Margulis.
That may help to explain some of the discussion about T-urf13. But it doesn't bode well for the acceptance of ID by the scientific community.
Cornelius: "Now, thanks to the latest research, we have the answer: calcium. "
ReplyDeleteI do not have access to Pubmed, but from what can be gathered from the abstract it seems that, at best, the conclusions in this paper should be considered only tentative. I certainly don't see that "we have the answer". Consider, for example, these extracts from the abstract:
"However, the molecules responsible for allorecognition probably evolved gradually before the Cambrian period, and some other (external) factor remains to be identified as the missing triggering event."
"The Cambrian explosion might have been triggered by the coincidence in time of primitive animals..."
Or does the actual paper say something more definitive? Either way, is there something so wrong with writing speculative papers? Isn't speculation a key practice of science that in turn could spark other research and investigation? Isn't this speculation in fact found in all branches of science?
After all, one could easily argue that much of the output so far of ID proponents is currently not much more than speculation (particularly given that if there is a designer, that entity is rather covert in its operations and methods).
Wow. The calcium increased the binding forces. This is the explanation for specified complexity?
ReplyDeleteCornelius, I suspect you are getting a little tired of me, but I promise I won't turn into a troll. I've promised myself I will limit the number of threads I comment on so as to not be too much of a pest. Nevertheless, I will comment on this one too since it goes into more detail of a point we were debating on another thread.
ReplyDeleteYour opening paragraph is, as far as it goes, true. But what you fail to mention is that AT THE TIME of the Cambrian Explosion, all major animal groups looked very similar. Every single mammal, bird, reptile, amphibian and fish which exists, or has ever existed since the time of the Cambrian explosion is represented there in a single worm-like species - Pikaia. The vast, phylum-wide differences between all species began as tiny, barely-significant differences. It is time and evolution which have spread them out into huge differences.
I have to say it feels to me like you are misrepresenting the facts. You have not lied, but the way you word the opening paragraph is very misleading. If I did not know about the Cambrian Explosion, I might, reading your OP, be led into thinking that mammals, birds, reptiles, amphibians and fish all appeared in the Cambrian Exlposion AS DIVERSE AS THEY ARE NOW. This is obviously not the case.
http://paleobiology.si.edu/burgess/burgessSpecimens.html
CWest:
ReplyDelete"it seems that, at best, the conclusions in this paper should be considered only tentative."
Thanks, I have edited the post.
Ritchie:
ReplyDelete"Cornelius, I suspect you are getting a little tired of me, but I promise I won't turn into a troll. I've promised myself I will limit the number of threads I comment on so as to not be too much of a pest."
Thank you for your thoughtfulness, but I am certainly not tiring of your posts. Please post away, particularly if you feel I am misrepresenting anything. As for your point about the first paragraph, I have modified it a bit as per your concern. Thx,
Cornelius: "Thanks, I have edited the post."
ReplyDeleteThe addition to your post is a quote another commentator from Science Daily on the paper, not something from the paper itself. But what does the actual paper itself say? Although the comment you provided seems to point to an "answer", the abstract of the paper still seems very tentative in its language. Have you read the paper yourself?
CWest:
ReplyDelete"The addition to your post is a quote another commentator from Science Daily on the paper, not something from the paper itself."
No, I also modified the text you were concerned with.
Ritchie
ReplyDeleteIt is my understanding that all major phyla made their appearance in the Cambrain. Tha means that there was great, sudden diversity
Cornelius -
ReplyDelete"Thank you for your thoughtfulness, but I am certainly not tiring of your posts. Please post away, particularly if you feel I am misrepresenting anything."
Thank you for being accommodating. I'll try not to take advantage of it too much...
natschuster -
"It is my understanding that all major phyla made their appearance in the Cambrain. Tha means that there was great, sudden diversity"
Not so. Imagine we turn around and look backwards through history. We look back 85 thousand years. What do we see? We see homo sapien sapiens leaving Africa. A single band of pioneers leaving the only continent on which humans existed at the time - a band which was about to spread and colonise the entire rest of the planet. All variations of human being outside of Africa can be found in that one small intrepid group. This does not mean that group of Africans looked very different from one another - they probably all looked very similar. But as they left and spread out, the differences in the descendants accumulated over time until we get the diversity we get in the non-African human races.
Let's look back a little further, to 65 million years ago. The KT extinction has wiped out much of the life on Earth, including the dinosaurs. A species of small shrew-like mammals has survived. They are about to thrive and multiply, and give rise to all the mammals. Whales, bats, kangeroos, humans, and all the other can trace their ancestry direct back to them. But for now, it is a single species.
Now let's look back further to 375 million years ago to when a species of fish, drags itself up onto land. It's descendants will become all the amphibians, reptiles, birds and mammals that will follow. But for now, it is a single species.
Now let's look back to the time of the Cambrian explosion, to an inch-long worm like species called Pikaia. This is only a single species, but its descendants will become all the fish, amphibians, reptiles, birds and mammals that will ever exist. But for now it is just a single species.
Do you see what this means? It means that when we say 'all today's major phyla appeared suddenly' we are in fact referring to a single species - a species which looked very similar to lots of other creatures around it. The same logic allows us to say 'All non-African humans appeared 'suddenl' 85,000 years ago", or "all mammals appeared 'suddenly' 65 million years ago'.
Ritchie:
ReplyDeleteYou are talking only about vertebrates. There was only one species of vertebrate. But the cambrain explosion included the numerous species of trilobite, brachiopods, sponges, the nautiloids, snails, bivalves, corals, lots of different kinds of worms, the anomalocaris, crinoids, etc, etc. There was tremendous diversty. Forty different phyla are represented,
natschuster -
ReplyDeleteYou are right of course, we have found all sorts of creatures fossilized at the time of the Cambrian Explosion. Creatures whose descendants would diversify into the abundant and diverse creatures we see around us today. But at the time of the Cambrian Explosion these creatures were relatively similar.
Compare the creatures at this link:
http://paleobiology.si.edu/burgess/burgessSpecimens.html
The trilobites, sponges, snails etc. you mention did indeed exist, but not in the tremendous DIVERSITY they exist in now. These fossils we have found are the first FEW ancestors of diverse groups. But they were not diverse themselves.
Besides, when we refer to an 'explosion', we do not mean life appeared suddenly on Earth - we are referring to an explosion in the fossil record. There had been life on Earth for billions of years already, but all of a sudden it starts to fossilize in significant numbers (possibly something to do with the development of hard armour, since soft parts don't tend to fossilize. This is at least one popular mode of thought).
There were fewer species in the Cambrain, but all the phyla that exist today were in the Cambrian. That means there was a wide variety of body plans.
ReplyDeleteNo, that's the point. There wasn't.
ReplyDeleteI'll give you an example - Pikaia, the tiny creature who was an early pre-cursor to all vertibrate animals was a small, worm-like creature. Then consider Canadia, whose an early cousin or ancestor of earthworms and leeches who was itself small and worm-like. Much like Pikaia. The representative of worms and leeches looked fundamentally practically identical to the representative of any modern vertibrate you can mention - giraffe, penguin, cat, duck, snake, elephant, shark or human.
When you rewind history 550 million years, what are today huge, phylum-level differences were absolutely trifling insignificant differences.
Not EVERYTHING was small and worm-like of course. Check out the link I posted in my previous comment. But many of these creature do follow very similar basic segmented body plans, give or take armour or growths such as feelers. I'm not saying all these creatures are practically identical, but they are not anywhere near as vast as the differences between phyla in modern creatures, so it is a mistake to think of it in those terms.
The amples on the link posted are only representative of a fraction of the entire Cambrian fauna. There were nautiloids and crinoids and brachipods, bivalves and snails and cnidarians. And the specimins on the link do show a great deal of variation. Some scientists want to put anomalocaris in its own phylum because it is so different than anything else.
ReplyDeleteNow this link:
http://paleobiology.si.edu/burgess/cambrianWorld.html
shows that there were lots of creature with a wide variety of body plans. Not just bilateral.
See, the pikaia might have looked superficially wormlike, but it had the crosshatched muscles and a notochord. A worm's internal anatomy is very different. Same thing with the various arthopods. Exoskelotins, jointed legs, etc. are very different than chordates.
ReplyDelete"And the specimins on the link do show a great deal of variation."
ReplyDeletePerhaps we are disagreeing here because the assertions are so subjective. There were indeed many other creatures in the Cambrian sea, and while we may think of them as varied in and of themselves They do not show nearly as much variation as we see in nature today.
I'm trying to get to the core of our disagreement. Do you perhaps imagine that all of a sudden, vast numbers of species suddenly appeared in the fossil record from nowhere which evolution cannot account for? Because this is not the case.
An explaination is certainly needed for the abrupt appearance of specimins in the fossil record (notice this does not necessarily reflect their abrupt appearance in the seas), but this is not something evolution cannot account for.
For one thing, some great scientists (most notably the late Stephen Jay Gould) advocate that evolution can sometimes work through punctuated equilibrium - occassional rapid bursts of evoltuion. Others say the change from calls and simple organisms to the creatures we see in the fossil record at the Cambrian Explosion was more gradual, but that creatures simply did not fossilize well before the Cambrian Explosion (it tend to be only a creature's 'hard parts' which fossilize - bones, teeth and armour. So perhaps the lack of fossils older than the Cambrian Explosion in fact signifies a lack of 'hard parts' in the creatures alive at the time).
Two competing theories, which both assume the truth of evolution. Doubtless there are others (the article above suggests the levels of calcium may have played a role). But if either is right, then the Cambrian Explosion is simply not a problem for evolution.
But both of these theories are almost apologetics. They are trying to explain the reason why evolution which is species to species change, is largly absent from the fossil record.
ReplyDelete... in this one very specific place in the rock strata.
ReplyDeleteEverywhere else the fossil record supports evolution by natural selection.
And the fact that the fossil record does indeed verify the predictions of evolution over the last 550 million years surely has to count for something?
"Calcium"...that's the explanation for the Cambrian Explosion. Please do not insult my or any one else's intelligence please. *sighs*
ReplyDelete