Soft Tissue Preservation Mechanism Stabilizes the Case for Earth’s Antiquity
One of the highlights of the year at Reasons to Believe (well, it’s a highlight for some of us, anyway) is the white elephant gift exchange at our staff Christmas party. It is great fun to laugh together as a staff as we take turns unwrapping gifts—some cheesy, some useless, and others highly prized—and then “stealing” from one another those two or three gifts that everyone seems to want.
Over the years, I have learned a few lessons about choosing a white elephant gift to unwrap. Avoid large gifts. If the gift is a dud, large items are more difficult to find a use for than small ones. Also, more often than not, the most beautifully wrapped gifts turn out to be the biggest letdowns of all.
Giving and receiving gifts isn’t just limited to Christmas. People exchange all types of gifts with one another for all sorts of reasons.
Gifting is even part of the scientific enterprise—with the gifts taking on the form of scientific discoveries and advances. Many times, discoveries lead to new beneficial insights and technologies—gifts for humanity. Other times, these breakthroughs are gifts for scientists, signaling a new way to approach a scientific problem or opening up new vistas of investigation.
Soft Tissue Remnants Preserved in Fossils
One such gift was given to the scientific community over a decade ago by Mary Schweitzer, a paleontologist at North Carolina State University. Schweitzer and her team of collaborators recovered flexible, hollow, and transparent blood vessels from the remains of a T. rex specimen after removing the mineral component of the fossil.1 These blood vessels harbored microstructures with a cell-like morphology (form and structure) that she and her collaborators interpreted to be the remnants of red blood cells. This work showed conclusively that soft tissue materials could be preserved in fossil remains.
Though unexpected, the discovery was a landmark achievement for paleontology. Since Schweitzer’s discovery, paleontologists have unearthed the remnants of all sorts of soft tissue materials from fossils representing a wide range of organisms. (For a catalog of some of these finds, see my book Dinosaur Blood and the Age of the Earth.)
With access to soft tissue materials in fossils, paleontologists have a new window into the biology of Earth’s ancient life.
The Scientific Case for a Young Earth
Some Christians also saw Schweitzer’s discovery as a gift. But for them the value of this scientific present wasn’t the insight it provides about past life on Earth. Instead, they viewed this discovery (and others like it) as evidence that the earth must be no more than a few thousand years old. From a young-earth creationist (YEC) perspective, the survival of soft tissue materials in fossils indicates that these remains can’t be millions of years old. As a case in point, at the time Schweitzer reported her findings, John Morris, a young-earth proponent from the Institute for Creation Research, wrote:
Indeed, it is hard to imagine how soft tissue could have lasted even 5,000 years or so since the Flood of Noah’s day when creationists propose the dinosaur was buried. Such a thing could hardly happen today, for soft tissue decays rather quickly under any condition.2
In other words, from a YEC perspective, it is impossible for fossils to contain soft tissue remnants and be millions of years old. Soft tissues shouldn’t survive that long; they should readily degrade in a few thousand years. From a YEC view, soft tissue discoveries challenge the reliability of radiometric dating methods used to determine the fossils’ ages and, consequently, Earth’s antiquity. Furthermore, these breakthrough discoveries provide compelling scientific evidence for a young earth and support the idea that the fossil record results from a recent global (worldwide) flood.
Admittedly, on the surface the argument carries some weight. At first glance, it is hard to envision how soft tissue materials could survive for vast periods of time, given the wide range of mechanisms that drive the degradation of biological materials.
Preservation of Soft Tissues in Fossil Remains
Despite this first impression, over the last decade or so paleontologists have identified a number of mechanisms that can delay the degradation of soft tissues long enough for them to become entombed within a mineral shell. When this entombment happens, the soft tissue materials escape further degradation (for the most part). In other words, it is a race against time. Can mineral entombment take place before the soft tissue materials fully decompose? If so, then soft tissue remnants can survive for hundreds of millions of years. And any chemical or physical process that can delay the degradation will contribute to soft tissue survival by giving the entombment process time to take place.
In Dinosaur Blood and the Age of the Earth, I describe several mechanisms that likely promote soft tissue survival. Since the book’s publication (2016), researchers have deepened their understanding of the processes that make it possible for soft tissues to survive. The recent work of an international team of collaborators headed by researchers from Yale University provides an example of this growing insight.3
These researchers discovered that the deposition environment during the fossilization process plays a significant role in soft tissue preservation, and they have identified the chemical reactions that contribute to this preservation. The team examined 24 specimens of biomineralized vertebrate tissues ranging in age from modern to the Late Jurassic (approximately 163–145 million years ago) time frame. These specimens were taken from both chemically oxidative and reductive environments.
After demineralizing the samples, the researchers discovered that all modern specimens yielded soft tissues. However, demineralization only yielded soft tissues for fossils formed under oxidative conditions. Fossils formed under reductive conditions failed to yield any soft tissue material, whatsoever. The soft tissues from the oxidative settings (which included extracellular matrices, cell remnants, blood vessel remnants, and nerve materials) were stained brown. Researchers noted that the brown color of the soft tissue materials increased in intensity as a function of the fossil’s age, with older specimens displaying greater browning than younger specimens.
The team was able to reproduce this brown color in soft tissues taken from modern-day specimens by heating the samples and exposing them to air. This process converted the soft tissues from translucent white to brown in appearance.
Using Raman spectroscopy, the researchers detected spectral signatures for proteins and N-heterocycle pyridine rings in the soft tissue materials. They believe that the N-heterocycle pyridine rings arise from the formation of advanced glycoxidation end-products (AGEs) and advanced lipoxidation end-products (ALEs). AGEs and ALEs are the by-products of the reactions that take place between proteins and sugars (AGEs) and proteins and lipids or fats (ALEs). (As an aside, AGEs and ALEs form when foods are cooked, and they occur at high levels when food is burnt, giving overly cooked foods their brownish color.) The researchers noted that spectral features for N-heterocycle pyridine rings become more prominent for soft tissues isolated from older fossil specimens, with the spectral features for the proteins becoming less pronounced.
AGEs and ALEs are heavily cross-linked compounds. This chemical property makes them extremely difficult to break down once they form. In other words, the formation of AGEs and ALEs in soft tissue remnants delays their decomposition long enough for mineral entombment to take place.
Iron from the environment or released from red blood cells promotes the formation of AGEs and ALEs. So do alkaline conditions.
In addition to stabilizing soft tissues from degradation because of the cross-links, AGEs and ALEs protect adjacent proteins from breakdown because of their hydrophobic (water repellent) nature. Water promotes soft tissue breakdown through a chemical process called hydrolysis. But because AGEs and ALEs are hydrophobic, they inhibit the hydrolytic reactions that would otherwise break down proteins that escape glycoxidation and lipoxidation reactions.
Finally, AGEs and ALEs are also resistant to microbial attack, further adding to the stability of the soft tissue materials. In other words, soft tissue materials recovered from fossil specimens are not the original, intact material, because they have undergone extensive chemical alteration. As it turns out, this alteration stabilized the soft tissue remnants long enough for mineral entombment to occur.
In short, this research team has made significant strides toward understanding the process by which soft tissue materials become preserved in fossil remains. The recovery of soft tissue materials from the ancient fossil remains makes perfect sense within an old-earth framework. These insights also undermine what many people believe to be one of the most compelling scientific arguments for a young earth.
Why Does It Matter?
In my experience, many skeptics and seekers alike reject Christian truth claims because of the misperception that Genesis 1 teaches that the earth is only 6,000 years old. This misperception becomes reinforced by vocal (and well-meaning) YECs who not only claim the only valid interpretation of Genesis 1 is the calendar-day view, but also maintain that ample scientific evidence—such as the recovery of soft tissue remnants in fossils—exists for a young earth.
Yet, as the latest work headed by scientists from Yale University demonstrates, soft tissue remnants associated with fossils find a ready explanation from an old-earth standpoint. It has been a gift to science that advances understanding of a sophisticated process.
Unfortunately, for YECs the fossil-associated soft tissues have turned out to be little more than a bad white elephant gift.
- Dinosaur Blood and the Age of the Earth by Fazale Rana (book)
- “What Dinosaur Soft Tissue Says about the Earth’s Age” by Fazale Rana (article)
- “Does Dinosaur Tissue Challenge Evolutionary Timescales? A Response to Kevin Anderson, Part 1” by Fazale Rana (article)
- “Does Dinosaur Tissue Challenge Evolutionary Timescales? A Response to Kevin Anderson, Part 2” by Fazale Rana (article)
- “Does the Recovery of Oils from a Fossilized Bird Evince a Young Earth?” by Fazale Rana (article)
- “Is Fossil-Associated Cholesterol a Biomarker for a Young Earth?” by Fazale Rana (article)
- “Can Keratin in Feathers Survive for Millions of Years?” by Fazale Rana (article)
- “Science News Flash: An Old-Earth Perspective on Dinosaur Feathers Preserved in Amber” by Fazale Rana (article)
- “Does Radiocarbon Dating Prove a Young Earth? A Response to Vernon R. Cupps” by Fazale Rana (article)
- Mary H. Schweitzer et al., “Soft-Tissue Vessels and Cellular Preservation in Tyrannosaurus rex,” Science 307 (March 25, 2005): 1952–55, doi:10.1126/science.1108397.
- John D. Morris, “Dinosaur Soft Parts,” Acts & Facts (June 1, 2005), icr.org/article/2032/.
- Jasmina Wiemann et al., “Fossilization Transforms Vertebrate Hard Tissue Proteins into N-Heterocyclic Polymers,” Nature Communications 9 (November 9, 2018): 4741, doi:10.1038/s41467-018-07013-3.