The Fossil Record

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July 13, 2012 Tags: History of Life

Today's entry was written by Keith Miller. Please note the views expressed here are those of the author, not necessarily of The BioLogos Foundation. You can read more about what we believe here.

The Fossil Record

Note: As Ted Davis has shown, support for the view that the earth is very old has been strong and widespread among evangelicals since the 19th century, even before Darwin came on the scene. Moreover, even many who don’t accept evolution agree that an old earth is compatible with a faithful reading of Genesis. But as an organization devoted to the study of God’s revelation in the creation through science, we especially celebrate the many different lines of physical evidence He has given us that all point to a planet that is 4.6 billion years old.

One of the first and still most compelling bodies of evidence for an old earth is the fossil record, and today we feature a re-post of part 3 of Keith Miller’s series on the Cambrian Explosion—the section that details the remarkable process by which the hard and even soft parts of ancient animals “return to the dust” in such a way as to preserve them as a record of the ancient past.

The Fossil Record: Is there enough evidence ?

There are two opposite errors which need to be countered about the fossil record: 1) that it is so incomplete as to be of no value in interpreting patterns and trends in the history of life, and 2) that it is so good that we should expect a relatively complete record of the details of evolutionary transitions within all or most lineages.

What then is the quality of the fossil record? It can be confidently stated that only a very small fraction of the species that once lived on Earth have been preserved in the rock record and subsequently discovered and described by science.

There is an entire field of scientific research referred to as "taphonomy" -- literally, "the study of death." Taphonomic research includes investigating those processes active from the time of death of an organism until its final burial by sediment. These processes include decomposition, scavenging, mechanical destruction, transportation, and chemical dissolution and alteration. The ways in which the remains of organisms are subsequently mechanically and chemically altered after burial are also examined -- including the various processes of fossilization. Burial and "fossilization" of an organism's remains in no way guarantees its ultimate preservation as a fossil. Processes such as dissolution and recrystallization can remove all record of fossils from the rock. What we collect as fossils are thus the "lucky" organisms that have avoided the wide spectrum of destructive pre- and post-depositional processes arrayed against them.

Soft-bodied organisms, and organisms with non-mineralized skeletons have very little chance of preservation under most environmental conditions. Until the Cambrian nearly all organisms were soft-bodied, and even today the majority of species in marine communities are soft-bodied. The discovery of new soft-bodied fossil localities is always met with great enthusiasm. These localities typically turn up new species with unusual morphologies, and new higher taxa can be erected on the basis of a few specimens! Such localities are also erratically and widely spaced geographically and in geologic time.

Even those organisms with preservable hard parts are unlikely to be preserved under "normal" conditions. Studies of the fate of clam shells in shallow coastal waters reveal that shells are rapidly destroyed by scavenging, boring, chemical dissolution and breakage. Occasional burial during major storm events is one process that favors the incorporation of shells into the sedimentary record, and their ultimate preservation as fossils. Getting terrestrial vertebrate material into the fossil record is even more difficult. The terrestrial environment is a very destructive one: with decomposition and scavenging together with physical and chemical destruction by weathering.

The potential for fossil preservation varies dramatically from environment to environment. Preservation is enhanced under conditions that limit destructive physical and biological processes. Thus marine and fresh water environments with low oxygen levels, high salinities, or relatively high rates of sediment deposition favor preservation. Similarly, in some environments biochemical conditions can favor the early mineralization of skeletons and even soft tissues by a variety of compounds (eg. carbonate, silica, pyrite, and phosphate). The likelihood of preservation is thus highly variable. As a result, the fossil record is biased toward sampling the biota of certain types of environments, and against sampling the biota of others.

In addition to these preservational biases, the erosion, deformation and metamorphism of originally fossiliferous sedimentary rock have eliminated significant portions of the fossil record over geologic time. Furthermore, much of the fossil-bearing sedimentary record is hidden in the subsurface, or located in poorly accessible or little studied geographic areas. For these reasons, of those once-living species actually preserved in the fossil record, only a small portion have been discovered and described by science. However, there is also the promise of continued new and important discovery.

The forces arrayed against fossil preservation also guarantee that the earliest fossils known for a given animal group will always date to some time after that group first evolved. The fossil record always provides only minimum ages for the first appearance of organisms.

Because of the biases of the fossil record, the most abundant and geographically widespread species of hardpart-bearing organisms would tend to be best represented. Also, short-lived species that belonged to rapidly evolving lines of descent are less likely to be preserved than long-lived stable species. Because evolutionary change is probably most rapid within small isolated populations, a detailed species-by-species record of such evolutionary transitions is unlikely to be preserved. Furthermore, capturing such evolutionary events in the fossil record requires the fortuitous sampling of the particular geographic locality where the changes occurred.

Using the model of a branching tree of life, the expectation is for the preservation of isolated branches on an originally very bushy evolutionary tree. A few of these branches (lines of descent) would be fairly complete, while most are reconstructed with only very fragmentary evidence. As a result, the large-scale patterns of evolutionary history can generally be better discerned than the population-by-population or species-by-species transitions. Evolutionary trends over longer periods of time and across greater anatomical transitions can be followed by reconstructing the sequences in which anatomical features were acquired within an evolving branch of the tree of life.


Keith Miller is research assistant professor of geology at Kansas State University in the United States. He is editor of Perspectives on an Evolving Creation (Eerdmans, 2003), an anthology of essays by prominent evangelical Christian scientists who accept theistic evolution. He is also a member of the executive committee of the American Scientific Affiliation, an association of Christians in the sciences, and a board member of Kansas Citizens for Science, a not-for-profit educational organization that promotes a better understanding of science.


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George Bernard Murphy - #71082

July 13th 2012

“Using the model of a branching tree of life, the expectation is for the preservation of isolated branches on an originally very bushy evolutionary tree.”

 

But the famous “evolutionary tree” illustration falls apart when you consider that every cell in the human body is a product of ENDOSYMBIOSIS. 

THERE IS DNA IN THER NUCLEUS FROM ONE ORGANISM…...

AND DNA IN THE CYTOPLASM FROM ANOTHER ORGANISM. 

They may be from DIFFERENT BRANCHES OF THE TREE.

The theory is that when our atmosphere became oxidizing the anaerobes were killed.

 But one little anaerobe got smart, ..[ all of my relatives are smart]... and it crawled inside another organism that had a cell membrane which protected it from oxidants. And these two organisms have lived together like that for about 2.25 billion years,..[ which is how long it has been since “THE GREAT OXYGEN EVENT”,..... SOMETIMES CALLED “THE GREAT OXYGEN CATASTROPHE”

And that is why,... boys and girls,..... you can trace the descent of your MOTHER, THROUGH THE MITOCHONDRIAL DNA OF YOUR CYTOPLASM,........... AND THE ANCESTRY OF YOUR FATHER THROUGH THE DNA OF THE NUCLEUS.

OXYGEN IS AN ESSENTIAL PART OF THIS STORY.


wesseldawn - #71110

July 15th 2012

If Eve “came directly from Adam’s (asexual creature) body (it gave birth to her) then mitochondrial Eve is a product of mitochondrial Adam!

 

Oxygen is the “breath of life” in Genesis 2:7 that created ‘living, breathing creatures’. Without it, nothing could be alive.


Francis - #71085

July 13th 2012

Keith Miller,

“Using the model of a branching tree of life ... ”

I didn’t think the “tree of life” was supposed to be used anymore. To confirm what I thought I heard, I just did a Google search for “inadequacy of tree of life+evolution”.  The top two results were from Biology Direct. Here are some words from one of the articles:

Three major transitions in early evolution are considered without recourse to a tree of life ...   Microbial genome evolution is not a treelike process because of lateral gene transfer and the endosymbiotic origins of organelles.” http://www.biology-direct.com/content/6/1/36/

 

The “tree of life” became firewood some time ago.

Unless you want to model a forest. Not two trees or even half a dozen. But a forest.

In fact, the Tree of Life is a metaphore [sic] for what is actual [sic] a forest of trees. Still, major mysteries are likely to persist, …” http://www.fossilmuseum.net/Paleobiology/CambrianExplosion.htm

 


George Bernard Murphy - #71087

July 13th 2012

Keith I think the TRee of life is baloney. along with LUCA, the last universal common ancestor.

 If you go to Day 3 of the creation schedule you see language suggesting God dumped a load of DNA on the globe when it was anoxic, and did not rotate.

 At about that same time the magma circulation which gave us plate tectonics began.

 If you dump any mass of DNA someplace where it can survive it will self-assemble into life forms.

[That is where those Darwinian icons, Mutation n Natural selection come into play.]

But the original DNA code did not assemble itselves and LUCA is a myth.

But by now “Darwinism” is a religious Myth too and you oppose it at your peril.

THE HIGH PRIESTS OF DARWINISM HAVE TERRIBLE WRATH.

 THEY WANT THEIR RELIGION TO EXPLAIN “ORIGINS”. AND IT DOESN’T.


Terry Taerum - #71171

July 17th 2012

All of these attempts to morph scientific discoveries into a 7-day story of creation illustrates how undeniable the evidence is that organisms evolve into other organisms - whether by epigenetic variations or by genetic mutation. There is simply not enough words in the story of creation for any interpretation of it to be considered a theory, in and of itself. A theory requires information conveyed in words. measures, formulas, and most important, an established framework based on experimental investigations of natural processes.

Evolution relies on the observed results of more than 3 billion years of natural experimentation, the results of which we can observe each and every day. The outcome of the 7-day creation experiment is the Sabbath, a token of a merciful God who demands rest from work. Doesn’t everyone wish their boss would demand rest?

One should not mix the religious with the scientific because they clearly serve different purpose.


KevinR - #71213

July 20th 2012

“A theory requires information conveyed in words. measures, formulas, and most important, an established framework based on experimental investigations of natural processes.”

Then please, show us the measures, formulas and the established framework and above all the investigations of natural processes of evolutionary theory. I’d be especially interested in the “natural processes” by which

a). Life came to be from nothing other than natural processes….and

b). How one creature transforms into another. Please do show us these very esssential evolutionary processes.

”..observed results of more than 3 billion years of natural experimentation,”

Firstly, just which results are you talking about? The fact that there are many fossils in the ground - just dead bodies? Or are you going to show us exactly how one creature transformed into another, step by step by step by step by step by step….?

Also, just how do you know it was 3 billion years? Did someone present you with a witnessed record of such tranfomation of creatures that you can claim to know it’s been 3 billion years? Was there anyone there to observe how the creatures transform from one into another over all that time? NO. Just coming up with  a “tree of life” and invented cladistics, does not make the presumed evolution a fact. It’s more a case of assuming evolution and then trying to fit the evidence to fit the paradigm.

“One should not mix the religious with the scientific because they clearly serve different purpose” 

Who says? By what authority can you make this statement?

If one were to read the bible one could certainly take the historic statements and put them to the test. For instance take the statement in Gen 1. that on the forth day God created the sun, the moon and the stars. That has all kinds of testable ramifications, even though it wasn’t necessarily a so-called “scientific” statement but rather one of historic fact. For instance, it implies that the solar system should display unmistakeable signs of being young - some thousands of years old, definitely not billions of years old as claimed by the evolutionists. This is testable and in fact the current real, physically observed  evidence in very much in favour of a young solar system. In fact the evidence brings out the utmost surprise in the atheist/evolutionist observers who expect the evidence to be in favour of their presumed billions of years. I can name statement after statement of such astonishment. I’ll start by mentioning the latest findings on Mercury:

An existing magnetic field that should not have been there after billions of years. They were expecting to find that mercury did NOT have a magnetic field.

A very abundant sulfurous content - contrary to evolutionary expectation that is should not be found there because sulphur should have been blown away by the solar wind.

Volcanic activity on Mercury - should have stopped long ago if it were billions of years old.

HUGE remnant magnetism in the rocks - totally unexpected to the point that they need to search hard to find a suitable explanatory “scenario” for it’s existence.

Even more devastating - mercury’s magnetic field is decaying rapidly instead of staying steady if the so-called dynamo theory was true. Plus the chances of it’s field being at the lowest point of reversal is just so much clutching at straws - and the observers KNOW it.

Another instance is the observation that even the most furtherest galaxies observed are all FULLY MATURE, containing billions of stars - and definitely not in the expected youthful state of evoluionary formation.

One can go on and on.


Francis - #71175

July 17th 2012

Terry Taerum,

“All of these attempts to morph scientific discoveries into a 7-day story of creation illustrates how undeniable the evidence is that organisms evolve into other organisms …”

I don’t understand how the second half of that sentence is supposed to follow from the first half.

And I definitely don’t understand the second half – “… how undeniable the evidence is that organisms evolve into other organisms …”.

Undeniable? What on earth are you talking about?


Darwin Guy Dan - #71182

July 18th 2012

In response to Miller, Francis wrote: “The ‘Tree of Life” became firewood.”  George wrote: “I think the tree of life is baloney, along with LUCA, the last universal common ancestor.”

I, DarwinGuy a.k.a. NaturalHistoryGuy, write  “Not a Tree; Not Even a Bush”:

I agree. I agree. It’s good to see you all also see. There is no Tree.  When push comes to shove, the history of life is also not a bush, not even a bush with a dove.

But do you also further see? Do you see that theosophical intuitive acts aren’t the facts? Rather observations, direct and indirect , are the acts that give us facts.

And so it is, as the Sun rises in the morning, the Sun is positioned approximately in the east. Do you see?  The Sun is over there beyond that little hilly. Anything else would be just silly.

And at noon, the Sun is above. But don’t look directly at that. No, rather look at, oh say, some dove.

And toward the evening, golly gee—- the Sun is in the west where it ought to be. There is no need to be conflicted. It’s just as I had predicted!

Facts are facts. Theories are theories. Ah gee, Ptolemy and Galileo agree!   I put in an order for a Nobel Prize.  I’ll let you know when it arrives.

Now get out your chart. Writing down all the facts for the record would make an excellent start.

A FEW NOTABLES: Lynn Margulis, author of THE SYMBIOTIC PLANET (1999); Carl R. Woese, origins of life researcher; Stuart Newman, inventor of the concept of DPMs, dynamic pattering modules. Also consider HOX genes as discussed by various authors.

Dan


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