Oldest vertebrate fossil found in Australia, scientists say

Farmerman, I have problems with dormant adaptive advantages and evolutionary throws of the dice. That notochord had a reason and my speculation would be quicker reaction time for the individual thus less likely to become "snack food". If it later proves useful for something else that's a plus in a dynamic environment. That's functionalist and reductionism I'll admit.

yes anything that implies a root purpose assumes a pre adaptation to any environmental condition.

Insect wings in the Silurian were just little nubs that appear associated with the structure that was dictated bythe hOx gene compliment and they had a thorax appendage that, initially, served little purpose. By the CArboniferous, these same nubs became cooling appendages and through (i assume) selection for larger and large wings(at least larger wings did not confer any negative function) arthropods with the largest wings , one Saturday afternoon, took off.
im a fan ofDave Raups "chuck the dice and see what comes up' theory, in that the morphological structure isnt considered an adaptive advantage until it succesfully matches an environment.
This is more easily explained by observing the fossils of the extinct beings and the environment that they stratigraphically inhabit.
in my field, Im always doing enviromental reconstructions for determining best locations of strat deposits of lag minerals (Im sort of an expert on titanium and rare earth minerals). i look for world wide equivalency in environments and see that many fossils are totally unsuited for life in that strat environment. so they are index fossils of use to industrial prospectors like me.
your point is well taken because we dont seem to have any precursors to this new australian form. even a simple chordate like todays amphioxus is really quite advanced compared to wormslike Odontogriphus(Walcott) and proto-arthropods like hallucigenia (Walcott). But, like the Pikaia, which was undoubtedly a chordate, thisOz guy appears to have been a mud crawler because the fossil appears to have a relict track behind it. Pikaia was a form that possibly just flapped its way through the benthic sediments and moved (my description) kind of like a flounder. we have no idea on its paleoecology, but im sure that some grad student is doing a motility dissertation on late Precambrian and early cambrian chordates.

im not denying that morphology cant quickly pace environmental changes.However, as per my discussion about winged arthropods, sometimes selective advantages dont get conferred for many zillions of years. so my original answer was more of a cop out based upon ignorance of the in-situ environment from which this "pikaia" like creature was found. im not agreeing that this is even a P gracilens because it may be already a vertebrate (although some spec is saying its just an annelid that was caught in some tectonic shortening) .
i, for one, am just gonna keep watching the Paleo newsletter and Geotimes for any new skinny on these critters.

" . . . Until it successfully matches the environment . . . "--thanks for that, it is a concise statement of what i had understood to be in operation. Lacking scientific knowledge of such matters, but being greatly interested in them, it is frustrating not to know if one understands what is being discussed. I understand that this is not a statement of universal truth, but it describes what i had come to think of as the most likely explanation of the evolutionary process, simply from a forensic viewpoint. It fits nicely with Occam's entia non sunt multiplicanda in that it does not posit complexities requiring a large amount of speculation on the nature of the mechanism.

Set,Or as I say sometimes, "If the toaster aint working, dont take it apart till you see whether it just needs to be plugged in"

Gould often said that "genera jump" mechanisms most often may have been pre-existing morphological features (and already recorded in the genic compliment) that only were manifest as a catastrophic environmental event accidently selects the individual for survival. I personally find that more believable rather than random mutation quickly coming up witha fitness scheme. The fossil record is way too loaded with failures to believe in purely gene driven evolution.

Gould frequently used the "Branching Bush" as his analogy of evolution. And its a fine analogy for combating the idea of progress in evolution, a notion which Gould battled for most of his life. However, it isn't really a very accurate analogy for describing the evolutionary process. It's unfortunate that it fails in some key areas because I've often thought that if we could find a more accurate analogy of the evolutionary process, that more people would appreciate the extraordinary nature of things.

One problem with the analogy of the Branching Bush is that twigs require their branches for survival. In the biological world, children usually outlive their parents, and within mere generations, the line that gave rise to the individual vanishes. If we try to apply this to the analogy of the bush, then the trunk of the tree must also vanish along with the branches, and all we are left with is a cloud of disembodied twigs expanding like a shock wave, away from a source long gone.

When we look at the biology around us at any given time, what we see are the echoes of the echoes, each one the source of a new explosion, and a brand new shock wave. The shock waves change with each echo and they fill every crack and crevice as the environment shifts around them. Some cracks close, while others are created, but the echoes fill them all.

The living echoes of the original genetic explosion which occurred here so many eons ago, are a reflection of the walls that they encountered along the way, and as such, it's important to remember that evolution itself is not a cause, it is a result.

Best Regards,

the branching bush is a "pop" analogy to discuss and explain how life radiated and evolved. It never meant that dinosaurs and their descendants were meant to live together. It more relates to the genetic 'permanent' record of the descendants from the parents. true the descendants survive and all we see are fossils of their parent lines, BUT the genome lives on unbroken and just added to. If there were no 'branches" the records of the genetic line from pikaia to man would have to be reinvented each time somebody went extinct.
This was the argument that ican always forwarded back on abuzz to try toconvince by sheer mass of mathematical improbabilities that there wasnt enough time to evolve a'man from a mouse"((even though they sit on different branches) and this, therefore , required some Intelligent leaning of the biome.
gould was never the author of the branching bush cponcept,(page 46 and 47 of his Wonderful Life give a nice rebuttal to the cone of diversity idea, all based upon the findings by Walcott at the burgess shale)

Your wish is my desire ... this time.

Better late than never, I hope!

Why do you wish I were here?

What is your favored theory regarding evolution's persistence in the face of great adversity? More specifically, why does evolution continue to try to evolve more intelligent life despite such life's lack of adequate capability to survive environmental disasters? Cockroaches have repeatedly done better? Why doesn't evolution stick with what works?

Why doesn't evolution stick with what works?. You have reified evolution. It is nothing more than a process. The response of living things to conditions as they are found at the present. What ever string is there is played out until something else comes along that is more adaptive and replaces it. If intelligence were maladaptive, it would be gone in an instant, to be replaced, perhaps, by cockroaches..

Knowing your past theories on the origins of species, I just called to ask you how you interpret this new finding?

PS, i have to agree with acquiunk on reification of evolution. youve never gone there before. im a bit surprisewd , unless youre just making a funny.

Please express in your own words a description of "this new finding".



Well, I was trying to make a funny.

The evolution process is allegedly influenced solely by undirected chance plus natural selection. The probability of such kind of evolution of the human genome within 10 billion years, starting with the human genome's common ancestor with the current mouse genome, is less than a moogolth [i.e., 10^(-1,000,000), 1 divided by 1 followed by a million zeros). Some say no problem, if there exist or existed an infinite number of universes, or if our universe has existed for infinite time. So I ask what evidence do you have that there exists/existed an infinite number of universes or our universe has existed for infinite years? I bet it's the same amount of evidence that I have that an infinite God exists: zero.

So, I attribute to the process of evolution some additional influence (e.g., physical and/or chemical) perhaps inherent in genomes themselves, or perhaps inherent in organic molecules.

Hi Ican,



This argument implies that the human genome (as is exists today) is the intended *target* of the process. But since the human genome was not a target, the calculation is incorrect.

To correct the calculation you must incorporate the fact that for the same period of time, and the same amount of variation, evolution would produce any of an infinite range of possibilities (which it does). Note that at this point in time, the planet is crawling with billions of different combinations of genomes (all of which have survived by virtue of the fact that they are here now).

no Ican, im not going to explain this finding when you only have but to read the article and go from there.

i can see that, from your attraction to gambling odds, you are still overly impressed with the impossibility of the evolutionary process.

i will only leave you with 2 points.

1 Once a morphological feature occurs , if it confers an advantage, it never has to be "reinvented" because it will proliferate . So if you count up all the unique features that separate a man from one of these ancient vertebrates, the list of new features gets briefer and briefer as time progresses.

2if you attribute this to an internal harwire of biotic molecules, then Ive always left you because youve never explained how a molecule can know when a meteorite will strike, or when the continent will split apart and you wind up with 2 totally7 different morphologies of the same genus on two separate continents. Which one doeas the pre wired molecule prefer/ Now if we split the continents , say six or eight ways, and isolate similar genera on 8 different homelands, which way is the preferred way fro that organic molecule to go? according to you, there is a WAY, that is the rIGHT WAY.

You dont have to fall into brane theory to follow evolution as a response to environmental change. 4 Dimensions suffice.. so, in my opinion, your entire second paragraph is just an attempt to try to sound erudite and it has nothing to do with anything .

Most all sciences start with observation, then interpretation. Youve made the leap by starting with a pet theory that you want so hard to believe , yet you totally dismiss ALL the observational evidence.

Hi rosborne,

First, I bet that neither of us has any observations/inferences that will show whether or not the human genome was a target.

Second, only if it is true that the evolution process consists solely of undirected chance mutations plus natural selection of resulting genomes, can it be fairly said there was/is no target. I bet that you do not have any observations/inferences that will show whether or not this is true. I bet I do!

Third, consider a lottery in which no given number is known to be a target. Suppose that nonetheless, that week after week the winning number is consistently found in a particular narrow range of all the possible numbers. Wouldn't you start to suspect an additional influence even though the lottery was supposed to not have a target? I would!

Fourth, the general trend in evolution is the evolution of increasingly intelligent critters that from time to time get wiped out, but continue to get re-evolved in new forms subsequently, none the less. I bet that evolution is biased (mathematically speaking, of course). We do not observe/infer from current evidence that there are now or ever have been infinite forms. In fact, it is alleged by almost all evolutionary scientists that the number of species hit a peak at about the time human critters evolved, and since then that number has been declining. Hmmmm?

When two animals -- one less intelligent and one moreso -- are competing, the more intelligent one is going to win out in times of adversity, all else being equal. Intelligence is a useful adaptation, like teeth. But just because there might be a perceived evolutionary push toward beings with teeth doesn't mean that the process is being prodded along by a toothsome creator.

I read the article. I understand that a fossil of a criter with a backbone was discovered. I understand that the fossil is alleged to be about 560 million years old. I understand that this criter, because of its age, is alleged to probably be the common ancester to all criters with backbones. I also understand from other sources, that criters with backbones were less likely to survive environmental disasters. Yet they repeatedly reappeared eventually in different forms subsequent to such disasters.

I do not undertand why you infer from this discovery that evolution does not have a propensity to develop backboned, increasingly intelligent life (a hypothetical target) despite the fact that such living organisms lack the ability to survive those environmental disasters as well as the backboneless less intelligent life.

I hypothesize that humans are in that class of living organisms that is the target. I infer you disagree. Why?

Yes, I agree: "all else being equal". But environmental disasters frequently made all else unequal. So the dumber life survived such disasters. Why?

Hi Ican,

The theory of Evolution says that the human genome is not a target. There are no targets. Since you are talking about variation and natural selection, I assume the standard theory of Evolution is what you are talking about.

If you want to propose some other explanation for things, then perhaps your calculations might relate, but within the standard model of evolution, they do not.



This is highly debatable (and specious), even without going into the rest of your paragraph. Intelligence certainly hasn't been the main driving force in insect evolution, despite the fact that they've been around longer than most fauna, and display huge variety in their genome.

Most experts can't even agree on a trend toward Complexity, much less intelligence.

Best Regards,

What other sources? Please provide web links. I would be interested in reading why creatures with a notochord would be less likely to survive the cambrian environment than other creatures.

Thanks,