Evolution Basics: Assembling Vertebrate Body Plans, Part 1

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October 3, 2013 Tags: Genetics, History of Life

Today's entry was written by Dennis Venema. You can read more about what we believe here.

Evolution Basics: Assembling Vertebrate Body Plans, Part 1

Note: This series of posts is intended as a basic introduction to the science of evolution for non-specialists. You can see the introduction to this series here. In this post we delve deeper into phylogenetic thinking and begin to examine the origins of our own group – the vertebrates.

In our last post, we introduced the distinction between “stem group” and “crown group” organisms, and discussed how the “arthropod body plan” – i.e. the body plan of crown group arthropods – arose through a gradual process. In this post, we’ll explore the origins of vertebrates, the group that would ultimately give rise to mammals such as our own species. Like arthropods, vertebrates make their first appearance in the fossil record in the Cambrian; and, as we have seen for arthropods, the vertebrate “body plan” shows signs of having been assembled over a lengthy period for exactly the same reasons – we see “stem group” organisms with only a subset of the traits characteristic of crown-group organisms. Before we discuss the origin and diversification of the vertebrates, however, let’s expand on a point we touched on briefly in the last post – the expectation that stem group species are not the direct ancestors of crown group species, but nonetheless are informative about the evolutionary lineage leading to the crown group.

Stem groups, direct ancestry, and transitional forms

As a scientist, reading popular news reports about biological discoveries is often a painful experience. Most news stories about fossil discoveries, for instance, are plagued with misconceptions. One very common misconception is that paleontology is the search for the direct ancestors of present-day organisms. While paleontologists are certainly interested in what the ancestors of present-day organisms looked like, paleontology is not well suited for finding direct ancestors. Counter-intuitively, however, this does not prevent scientists from learning a great deal about lineages leading to a present-day crown group. Let’s use human family trees as an analogy to explain why this is the case.

With “Venema” as a last name, it won’t be a surprise that my ancestry is rooted in the Netherlands. If I were to travel to the Netherlands and visit a medieval graveyard, the chances that any particular grave would hold the remains of one of my direct ancestors would be tiny. On the other hand, studying the remains of anyone in the graveyard would be highly informative about my ancestry, because nearly all individuals found there would be (fairly) close relatives of mine. In other words, I would share an ancestor in common with them – though some number of generations back. If I were to call my own immediate family a “crown group,” then these relatives that branch off my direct lineage a few generations back would be analogous to “stem groups” – and studying the characteristics of these “stem group” relatives would be an excellent way for me to learn about my own lineage, even if I knew nothing about it directly, since I would be studying close relatives of my direct ancestors.

So too with fossil species: the probability that any given fossil species is a direct ancestor of a modern-day species is vanishingly small. Fossilization is a highly infrequent event – fossils spaced 10,000 or even 100,000 years apart would be considered to be nearly simultaneous in their timing from a geological perspective – and the chances of such an infrequent event preserving a direct ancestor is highly unlikely. On the other hand, the probability that the fossil record preserves relatives of modern-day species is quite good, though these relatives might be fairly distant ones (certainly much more distant than the relatives I might find in a Dutch cemetery).

Let’s briefly return to the diversification of arthropods to illustrate what we mean. In the phylogeny below, the direct lineage of crown-group arthropods is outlined in blue, and various stem-groups branch off this lineage along the way. Studying these stem-group species allows us to infer what characteristics were present at different time points along the direct crown-group lineage, and the order in which the characteristics were acquired.

Timeline: Lineage of crown-group arthropods

For example, because we see stem-group arthropods with specialized appendages and body segments (but without a hardened exoskeleton) we can infer that these characteristics arose first on the lineage leading to the crown-group. Note well – these stem-group species (X1, X2 and X3 on the diagram above) are not ancestors of crown-group arthropods, but relatives. Put another way, they arenot transitional forms leading to the crown group. They are, however, species that give us information about the actual transitional forms on the direct crown-group lineage. In this way, the stem-group species display transitional characteristics – the stepwise accumulation of traits that we use to define the crown group.

Another point worth mentioning here is that because stem-group species are not ancestors of the crown group, there is no expectation that they will be older than the last common ancestral species that ultimately gives rise to the crown group. For example, the stem-group species in the diagram above (X1, X2 and X3) are all species found in the fossil record alongside crown-group species. At the time point marked by the dashed red line, for example, it would be no surprise to find additional species that were stem-group species with one, two or three crown-group characteristics. Once lineages separate, they are independent of each other.

(As an aside, it is fairly common to see misunderstandings of these concepts in the popular press and in Christian antievolutionary writings. Often, the above phylogeny would be interpreted as species X3 being the direct ancestor of species X2, which is in turn the direct ancestor of species X1, which in turn is the direct ancestor of the modern-day species. At times this (erroneous) expectation is even specifically derided as impossible, since (for example) species X2 appears in the fossil record later than species X1, even though species X2 is “supposed to be the more primitive species.” The misunderstanding arises from (a) the expectation that evolution is a ladder-like progression directly towards present-day species rather than a branching tree of related species and (b) the expectation that the fossil record shows us the preconceived direct progression of transitional forms rather than an infrequent sampling from various parts of the branching tree.)

The origins of vertebrates

With these concepts in place, then, we are, at last, ready to delve into the Cambrian origins of our own group – the vertebrates. As you now understand, seeking to understand the origins of the defining characteristics of vertebrates is to look for stem groups on the vertebrate lineage and examine their characteristics.

Vertebrates are a monophyletic group nested within a larger group known as chordates, which means that understanding vertebrate evolution requires us to examine chordate evolution first. Chordates are defined as organisms that have (1) a hollow dorsal nerve cord, (2) a rod-like, flexible structure called the notochord, (3) a pharynx (with pharyngeal openings, sometimes referred to as “gill slits”) and (4) a tail that extends past the anal opening (a “post-anal tail”). Vertebrates have all of the features of chordates, but add others, such as a (5) brain encased within a skull, and (6) a backbone that replaces the embryonic notochord later in development. As you might expect, there are several Cambrian stem-group species on the vertebrate lineage that allow us to see how the defining vertebrate characteristics were assembled over time – a topic we will explore in our next post.

For further reading

Budd, G.E. (2008). The earliest fossil record of the animals and its significance. Phil. Trans. R. Soc. B 363, doi: 10.1098/rstb.2007.2232
http://rstb.royalsocietypublishing.org/content/363/1496/1425.full

Budd, G.E. and Telford, M.J. (2009). The origin and evolution of arthropods. Nature 457, 812-817 doi:10.1038/nature07890

Swalla, B.J. and Smith, A.B. (2008). Deciphering deuterostome phylogeny: molecular, morphological and palaentological perspectives. Phil. Trans. R. Soc. B 363, doi: 10.1098/rstb.2007.2246
http://rstb.royalsocietypublishing.org/content/363/1496/1557.long

 


Dennis Venema is professor of biology at Trinity Western University in Langley, British Columbia. He holds a B.Sc. (with Honors) from the University of British Columbia (1996), and received his Ph.D. from the University of British Columbia in 2003. His research is focused on the genetics of pattern formation and signaling using the common fruit fly Drosophila melanogaster as a model organism. Dennis is a gifted thinker and writer on matters of science and faith, but also an award-winning biology teacher—he won the 2008 College Biology Teaching Award from the National Association of Biology Teachers. He and his family enjoy numerous outdoor activities that the Canadian Pacific coast region has to offer. Dennis writes regularly for the BioLogos Forum about the biological evidence for evolution.

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Glenn Dell Kasper - #82783

October 3rd 2013

Quote: So too with fossil species: the probability that any given fossil species is a direct ancestor of a modern-day species is vanishingly small. Fossilization is a highly infrequent event – fossils spaced 10,000 or even 100,000 years apart would be considered to be nearly simultaneous in their timing from a geological perspective – and the chances of such an infrequent event preserving a direct ancestor is highly unlikely.

Not so highly unlikely at all ... for example coelacanths have been fossilized for several hundred millions of years (supposedly) and yet we have been catching them alive since the 1940s! Me personally…I believe that the assumption of a very long time is erroneous. After reading your “what we believe” section and reading your argon dating method assumptions…okay namely…that the formation of the rock came through a molten process whereby all the argon was boiled off so that the radiometric age was set at zero because there was no argon in the rock so that the only argon found later was from radioactive decay is erroneous. God could certainly have placed it there, perhaps so that he would not leave too obvious of a footprint.


Matthew Winegar - #82802

October 7th 2013

Quote: “Not so highly unlikely at all ... for example coelacanths have been fossilized for several hundred millions of years (supposedly) and yet we have been catching them alive since the 1940s!”

I cannot speak to this example (a citation would be nice), but I think Dennis’ point was that most fossils we have are unlikely to be a direct ancestor of species that are alive today, not that there are no examples of direct ancestors being fossilized.

Quote: “God could certainly have placed it there, perhaps so that he would not leave too obvious of a footprint.”

That is speculation, but theologically does not seem plausible to me, as you seem to be indicating that God would create a world with physical characteristics that are deliberately misleading to his creation.  I see it as inconsistent with his character and his Word.



Glenn Dell Kasper - #82803

October 7th 2013

Sure…here ya go. http://www.dinofish.com/

And me I see thousands of feet of solid rock layers all perfectly parallel and not in straight lines. These are rock layers supposedly millions years in forming…there is no way for the lines to perfectly parallel and be millions of years between layers and ...and this is the young earth part… be perfectly parallel and not perfectly curved (barely i.e. conforming to the earth’s curvature) AND be layed down over millions of years. To me it looks like a very catastrophic event…a global flood.

And no it is not misleading…it spells out all how it got like it is in the pages of the bible. The fossil record is nothing more than a hydrologically sorted catestrophic layering of what was on the earth when the global deluge hit the earth.


glsi - #82797

October 5th 2013

Glenn,

Evolutionists are forever claiming that fossilization is such a rare event that it makes it too difficult or impossible to prove their case.  Fossilization may well be a rare event, but the reality is that they are found all the time.  The trouble is, they show stasis and not the gradualism that Darwinism predicted and desperately needs.  It’s unfortunate and truly shameful that this basic information isn’t pointed out to high school biology students in the mainstream textbooks.  It seems they’d rather serve up theory than facts.

I like to go directly to evolutionary biologists for this type of information.  You can find it when you dig through the debates and arguments they have with each other even if they try to hide it from impressionable high schoolers.  Here is Dr. Lynn Margulis (former spouse of Dr. Carl Sagan) from the University of Massachusetts Amherst:

“What you’d like to see is a good case for gradual change from one species to another in the field, in the laboratory, or in the fossil record—and preferably all three.  Darwin’s big mystery was why there was no record at all before a speific point (dated to 542 million years ago by modern researchers), and then all of a sudden in the fossil record you get nearly all the major types of animals.  The paleontologists Niles Eldredge and Stephen Jay Gould studied lakes in East Africa and on Caribbean islands looking for Darwin’s gradual change from one species of trilobite or snail to another.  What they found was lots of back-and-forth variation in the population and then—whoops—a whole new species. There is no gradualism in the fossil record.”


Glenn Dell Kasper - #82804

October 7th 2013

And not to mention the spontaneous generation of life itself. If God created the first one celled organism and then evolved the rest then why does the bible not say that? You mean God can create a universe as complex as it is and yet he somehow cannot tell us how he did it? And the bible is very clear death came through sin therefore evolution (a death necessary process) cannot be unless the bible is not true.


Jon Garvey - #82806

October 8th 2013

The problem of the alleged paucity of the fossil record can surely be addressed by the same kind of statistical tools used in field biology.

Donald Prothero, some years ago, quoted a figure of 250K categorised fossil species, and estimated that to be only 5% of the actual number of species. But that, of course, depends on the assumption of gradual evolution, which given maybe up to 5m living species, would suggest a hugely greater number of extinct species than those actually found. 5% would be a rather over-conservative estimate in that case.

On the other hand, if the  same pattern consistently observed in the rocks - that of stasis and relatively rapid speciation - represents reality, the 250K preserved as fossils would be a much more significant fraction of all that have lived. The data should drive the theory, rather than vice versa - but is the fossil record so unreliable that data have to be constructed from the theory (or simply put in the tray marked “future findings” as Charles Darwin did)?

But in field biology you can estimate total populations from samples, and the same ought to be true in palaeontology. If fossils are vanishingly rare, but evolution slow and gradual, then one ought to find small sample sizes but of very many species. So duplicates would be rare, and constant change the pattern found. Whereas if mutagenesis works by stasis/sudden transition one ought to find comparatively large samples of fewer species.

In other words, it is misleading to look only at the number of species - one needs to account for the number of specimens of each species.

Some months ago I used the British Natural History Museum’s website figure of “several million fossils for each major museum” to estimate that there are perhaps 200m classified fossils in museum collections. Subsequently I read an estimate in the publisher’s blurb for Feathered Dinosaurs - The Origin of Birds of 1 billion specimens. In either case it’s a vast  number - it represents an average of between 800 and 4000 specimens for each fossil species described by science.

Tracking that to individual species shows that the sample pattern often tends to compensate for any vagaries of preservation: for example, the dozen Archaeopteryx specimens all come from one formation, which could therefore be a freak of preservation. But Iguanodon is known from large numbers of species across Eurasia and North Africa, all now believed to be from one, or maybe two, species. The thirty T. Rex specimens found so far were scattered across western N America. Hyracotherium, known from just one species at the “root” of the equine family tree, has been found as “hundreds” of specimens across the northern hemisphere - far, far more than the total number of genera and species ascribed to the whole evolutionary tree of the horse.

To me that puts Darwinian gradualism on a very unsteady palaeontological footing, just as it was in Darwin’s time, and underlines the lament of Niles Eldridge that “evolution always seems to happen somewhere else.”


glsi - #82814

October 8th 2013

Very interesting.  Thanks for taking the time to write that up.


Dennis Venema - #82838

October 10th 2013

Jon, a few comments:

The fossil record is not going to provide transitions between species, except in rare circumstances where fossilization is very likely. It’s simply too infrequent in most cases. Consider the wolf—> dog transition we discussed in this series a while back - there is no fossil record to speak of that documents this transition. A future paleontologist would find wolves, and in slightly higher strata perhaps a dachshund - with nothing to bridge them unless they were very, very fortunate indeed.

In order to have a reasonable chance of fossilization, the species in question needs to have a large population over a long period of time - so, the fossil record is biased towards such species.

At a higher level, however, there are “transitional forms” - i.e. stem group species with intermediate characteristics - all over the place. Fish to tetrapods, tetrapods to birds and mammals, and so on. You can see some of this evidence in the next post in this series (as well as in upcoming posts). So, over longer periods of time, the fossil record does show us transitions.

Also, don’t forget that the fossil record is only one line of evidence here - comparative genomics has shown us a lot that the fossil record never could, and the evidence there is also for gradual change (and that a small amount of genetic change can effect large changes in morphology).


glsi - #82840

October 10th 2013

More from Dr. Margulis, University of Massachusetts Amherst:

“But neo-Darwinists say that new species emerge when mutations occur and modify an organism.  I was taught over and over again that the accumulation of random mutations led to evolutionary change—led to new species.  I believed it until I looked for evidence.”

Dr. Margulis passed away recently at a fairly mature age and spent her entire life looking for this type of evidence.  So I guess the conclusion I can draw is that the evidence that Dennis is claiming to possess must be quite ambiguous and very much in the eye of the beholder.  


Jon Garvey - #82845

October 11th 2013

Dennis

You either missed, or didn’t answer my point, which was not about the number of species represented by fossils, but the number of individuals of those species.

What if palaeontologists find several hundred wolves and several hundred daschunds, all scattered across different continents and geological formations, with no intermediate fossils whatsoever? Many would conclude that the rocks are telling a real story, not just reflecting a poor record, ie that most species do not evolve along a phyletically gradual continuum, but that speciation is relatively fast, relatively localised, and therefore likely to involve factors other than those seen in routine microevolutionary situations.

Evolutionary stasis is a serious enough issue to have troubled as celebrated a scientist as Gould, as well as Mayr and Darwin before him and many others down the line, expecially palaentologists who would, one expects, know more about the vagaries of fossilisation than anyone.

High level transitions tell us nothing, per se, about whether those are gradual, saltational or somewhere in between. The evidence that small genetic changes can produce large morphological changes makes stasis even more remarkable a phenomenon. In those cases (the majority in the fossil record) large genetic changes occurring through drift or selection (sometimes across changing environments and climatic epochs lasting millions of years) do not cause large morphological change.

Isn’t it a basic principle that if the same mechanisms produce different effects at different times - stasis or speciation/high level transitions - then the difference is due to other factors?


Dennis Venema - #82860

October 11th 2013

Hi Jon,

My point is that what would seem like a large transition from a fossil perspective (wolf to dachshund) is in fact a gradual transition (as we know, since humans watched most of the transition take place). There is a clear, gradual link between wolves and dogs, and at no point is is necessary to evoke anything beyond small, incremental genetic changes. If in the future dachshunds form a large population and thus enter the fossil record, they would appear, geologically, as a new “species” closely related to wolves. Finding “transitional forms” between wolves and dogs would take intense effort, and might be accomplished (say, by finding other dogs related to dachshunds but not direct ancestors of dachshunds).

If a small population branches off and changes (as in the case of the lineage branching off from wolves and leading to dogs), we won’t see that change until the new species has a large enough population to have a reasonable chance of entering the fossil record.

So, what appears geologically as a “sudden” appearance is in fact gradual at the organismal level.


glsi - #82869

October 11th 2013

Dennis,

The facts according to Mayr are pretty stark:

“What one actually found was nothing but discontinuities: All species are separated from each other by bridgeless gaps; intermediates between species are not observed . . . The problem was even more serious at the level of the higher categories.” (Mayr, E., Animal Species and Evolution, 1982, p. 524.)

And yet you’re saying above that transitional forms at a higher level are “all over the place”.   Quite a discrepancy here.  It seems very obvious  that there are myriad gaps and that the reason(s) for the gaps are a matter of speculation and opinion.   


Dennis Venema - #82881

October 12th 2013

glsi,

I don’t have a copy of Mayr, 1982 handy, so I can’t check the wider context of the quote, or the content omitted by the elipsis. Do you have the book?

I suspect the quote is referring not to the state of paleontology in 1982, but looking back in history (note the use of the past tense, etc). Back in Darwin’s time, for example, this would have been the state of the science.

Even if the quote was Mayr’s impression of the evidence in 1982 (which I’m doubtful of), that was over 30 years ago. We’ve found a lot of stem-group species since then - mammal-like reptiles, reptile-like mammals, several feathered dinosaurs, stem-group tetrapods, stem-group whales, stem-group hominids, and so on.


glsi - #82884

October 12th 2013

Dennis,

No, I don’t have the book.  You can google the quote and original context as easily as I can and you’ll find it is what it is.  It is truly wonderous that today anyone with an internet connection can find information like this without having their own extensive library or be privledged enough to be an academic with access to specialized data banks.  I know this equaling of the field is frustrating to some academics who would prefer to control the information themselves and dole it out as they see fit according to their own agendas.  I realize that’s not the case here at BioLogos.

Anyway, here’s something much more recent from Mayr which is hardly different from what he’s saying in 1982:

” Given the fact of evolution, one would expect the fossils to document a gradual steady change from ancestral forms to the descendants.But this is not what the paleontologist finds. Instead, he or she finds gaps in just about every phyletic series. New types often appear quite suddenly, and their immediate ancestors are absent in the earlier geological strata. The discovery of unbroken series of species changing gradually into descending species is very rare. Indeed the fossil record is one of discontinuities, seemingly documenting jumps(saltations) from one type of organism to a different type. This raises a puzzling question: Why does the fossil record fail to reflect the gradual change one would expect from evolution? “(Ernst Mayr-Professor Emeritus, Museum of Comparative Zoology at Harvard University, What Evolution Is, 2001, p.14.)

And then Mayr goes on to describe, much as you do, the rarity of fossilization.  Nothing unusual there. What’s important here are the bald-faced facts of the fossil record, not what type of spin he would like to add to it.

 

 



Sean Dillon - #83173

October 24th 2013

The passage in “The Growth of Biological Thought” was, as Dennis anticipated, a description of outdated historical objections to Darwinian evolution. At the end of the same passage, Mayr states:

“As a result the traditional objections were raised again and again, up to recent times, most forcefully by Schindewolf (1936), Goldschmidt (1940), and some French zoologists (Boesiger, 1980). It was not until the period of the new systematics that Rensch, Mayr, and others demonstrated the populational origin of the discontinuities (Mayr, 1942; 1963) and that the geneticists supplied the evidence on the variation needed to permit natural selection to be effective.”

In short, this is an outdated objection, drawn from some quote mine, which gives a deeply misleading impression of Mayr’s views on the subject.

I managed to bring the page up once on Google Books, but then the preview elided it… not sure why. 


Sean Dillon - #83174

October 24th 2013

As for the more recent quote, it is a similar situation. Mayr sets up the problem and then (outside the context of this mined quote) proceeds to give the solution. He points out that (despite the rarity of fossilization) several major lineages—dinos to birds, therapsids to mammals, land mammals to whales, apes to humans, ancient to modern horses—are now stairstepped in very small incriments by robust series of transitional fossils… exactly as the Theory of Evolution predicts.

Quote, in the instance of therapsids to mammals: “Some of these fossils appear to be so intermediate between retiles and mammals that it is almost arbitrary whether to call them reptiles or mammals.”


glsi - #83246

October 26th 2013

Hi Sean,

I’m sure you must realize Ernst Mayr is widely recognized as one of the 20th century’s leading evolutionary biologists.  As such his opinions about neo-Darwinism are quite well known, but I’m glad you’ve been able to pull some in case there are any readers who are unaware.  This is why it’s so wonderfully effective to use his factual descriptions of the fossil record as I’ve been able to do.  Thanks for contributing here.


Jon Garvey - #82885

October 13th 2013

I guess it would just be nice to discuss the actual refutation of those in biology who are looking beyond Neo-darwinian mechanisms, rather than simply blanking their critiques and new insights as if they were the obscurations of Creationists or IDers. Ernst Mayr, I agree, is of a previous generation, but what about Denis Noble, Stuart Newman, Eva Jablonka and Marion Lamb, Gerd Muller, Massimo Pigliucci, Jim Shapiro… (to name but a few of many)?

These all come from different disciplines, mostly affirm mutation and natural selection as part of the process, but usually criticise excessive concentration on the individual gene, and begin to explore the interrelating roles of epigenetics and other neo-Lamarckian phenomena actually observed to occur; developmental biology, HGT, symbiosis and other sources of saltational change (also observed in the field); physiology, targeted mutation, niche-construction and other active participation of the organism in its own evolution… all these and more are exciting and challenging areas. And in the context of the present discussion almost all of them open the strong possibility that the fossil record reflects mechanisms radically different from adaptive gradualism, rather than the mere incompleteness Darwin first proposed 150 years ago.

Opposition to these guys, as typified by Jerry Coyne’s “they just don’t understand evolution” approach, seems usually more ideological than scientific. These are all established scientists in their fields, and it would seem worthwhile, in 2013, giving them due attention if covering evolution “as she is spoke” now..

For those interested, one article on the challenge to Neodarwinianism picked at random from many possible: http://www.somosbacteriasyvirus.com/soft1.pdf


hanan-d - #82890

October 13th 2013

Jon,

Let me ask you a question out of ignorance. What does the fight over neoDarwinianism give you? All those people you mention are still Darwinians in the sense that they believe in natural selection. So eliminating neoDarwininism gives you what? That random mutations don’t exist and don’t contribute to natural selection, therefore giving the possibility that God did not roll the dice? That in fact, we were planned from the beginning?

 

thanks.


Jon Garvey - #82894

October 14th 2013

To be honest, hanan-d, my beef with the Modern Synthesis is very much less important to me than my beef over bad theology. The biologist in me just doesn’t buy it as adequate in 2013.

Theologically, if there’s an adequate set of efficient causes in the material realm for all we see in “nature”, obviating the need for special miraculous intervention, that’s what I’d expect to find - it would be the material and formal means by which God, as the final cause, created all things. As a classical theist - a Calvinist, in effect - I don’t make a big distinction between the natural and the supernatural: they are both varieties of God’s working, not separate power-domains. “Natural causes” are no threat to divine action, because they are divine action.

It’s long seemed to me that the N-D synthesis is such a blunt instrument that it almost requires miraculous tinkering - it’s like expecting God to use a broom to paint a miniature. Hence TEs here going on about God being happy to call anything intelligent that evolution threw up “man”.

So in providing a more subtle and flexible “palette” the new science just looks more capable of doing both the heavy lifting and the fine work - without, that is, downgrading God’s creation to a Deist conception of lighting the blue touch paper and standing well clear.

All that depends on an adequate doctrine of providence, which in my view much American evangelicalism has lost through rejecting (or forgetting) the heritage of those who did hold such a doctrine - the best pre-Christian Jewish philosophy (and much Jewish and even Muslim thought from the common era too), the Church Fathers, the Scholastics, the Reformers, the first (19th century) generation of Theistic Evolutionists… between Charles Finney and the Higher Critics most of that has been buried.

The really toxic combination to faith is the combination of a theology that downgrades God’s intimate interaction with every event (to be replaced by a grandfatherly dice-roller), and a scientific approach that stresses contingency as a matter of principle.

What you get is a laissez-faire, gambling God who may as well not be there. So for many who buy the approach, God will become increasingly marginal - as he was for Darwin.

But it ain’t necessarily so, believe me.


Glenn Dell Kasper - #82886

October 13th 2013

Yeah glsi!

If fossization is such a rare event and if evolution is true…then finding the same species in different geographic regions in the “supposed” same strata should be a most rare event…which makes the current known fossil record more indicative of a global deluge.


Paul Lucas - #82935

October 16th 2013

Glenn: “your argon dating method assumptions…okay namely…that the formation of the rock came through a molten process whereby all the argon was boiled off so that the radiometric age was set at zero because there was no argon in the rock so that the only argon found later was from radioactive decay is erroneous. God could certainly have placed it there, perhaps so that he would not leave too obvious of a footprint.”

First, Glenn, let me talk about the difference between an “assumption” and an “inference”.  An assumption has no evidence, while an inference is an extrapolation based upon evidence/observations.    Saying volcanic rock was formed from molten rock is an inference.  The granules provide one evidence of this.  However, let’s remember we see volcanic rock forming today from molten rock.  Volcanic rock identical in form and chemical composition to that found in deposits.

Now, let me address the comment that God could have put argon into the rock so that He would make it look old.  You say “not leave too obvious a footprint”.  That is very tactful, but it comes down to God making the earth look old when it is young.  Forget tact, that is a lie.  A baldfaced lie.  As Christians, we cannot accept that argument that God somehow made the earth look old but it is not.  Especially since it is so easy to have the earth look young.  We as Christians cannot tolerate God as a liar.  You still have God, but now He is not a god we can worship.  After all, we cannot worship the Prince of Lies, can we?  We rely upon God telling us the truth—always.  Why? Because we have to trust God when He speaks of essential things that we can’t verify:  eternal life, that He really will forgive our sins, etc.  Those are essential to our belief in God, and they rely on absolute trust.  Once God lies, we can’t trust Him anymore.  On anything.

So, the argument that God put the argon back in and now the rock looks old is one that rationalizes what we see in God’s Creation, but the price of that argument is way too high.  The price is abandoning Christianity.  This is what Rev. Charles Kingsley wrote to the man who first proposed that God only made the world look young:

“I cannot ...believe that God has written on the rocks one enormous and superfluous lie for all mankind. To this painful dilemma you have brought me, and will, I fear, bring hundreds. It will not make me throw away my Bible. I trust and hope. I know in whom I have believed, and can trust Him to bring my faith safe through this puzzle, as He has through others; but for the young I do fear. I would not for a thousand pounds put your book into my children’s hands.”

Like Kingsley, not for any amount of money would I show your post to my children.


Sagegrouse - #82998

October 18th 2013

Creationists and Old Earth Evolutionists often defend their respective turf because both believe that ultimate reality is being attacked.  The Creationist believes that if the plain meaning of Genesis is overthrown, nothing in the Bible is reliable.  It is easy for Old Earthers to forget this, since they are accustomed to non-literal biblical interpretation.

The Old Earther believes that nothing in the world is reliable if the earth is young, for the natural evidence is so compelling for an ancient earth.  It is easy for the Creationist to forget this, since they are often unaware how untenable the Creationist explanations for the data are.

So the defense of reality is pitted against the defense of reality.  But the Bible often interprets itself in a non-literal fashion, even when a literal interpretation was expected.  On the other hand, physical facts are never figurative and have authority from God to falsify any religious claim.  As Jesus said, “If I do not do the works of my Father, do not believe me.”

It seems then that we have to take the physical facts as they stand.  If they compel a figurative reading of a Bible passage, God has not overthrown the Bible, he has only taught us to take that passage figuratively.


Glenn Dell Kasper - #82999

October 19th 2013

Your Gos is too small for you. Your assumption that the earth was once all molten is why it looks old. Perhaps God did not create it that way.

Me I offer an explanation…a guess as to why…perhaps he did it the way he did (with Argon in the rocks) just so you would have to believe in him. That is my guess as to why.

Some artists don’t sign their paintings some do…God may have placed argon in the rock because that is just the way he did it and “signed his painting” with his bible.


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