Today’s New Reason To Believe

Posted by Fazale ‘Fuz’ Rana, Ph.D.

New Understanding of Precambrian Fossil Tracks Makes Biology’s Big Bang More Explosive

I have three teenage daughters. They are good kids, but—as all teenagers are apt to do—they occasionally try to get by with things they shouldn’t. Usually when my wife or I suspect that something is amiss, my daughters will try to talk their way out of it by coming up with a story to defuse our suspicions. Still, it’s usually pretty easy to figure out that things are not on the up and up when all the facts don’t match their explanation.

This is also the case when it comes to the theory of biological evolution. Evolutionary biologists have constructed reasonably plausible scenarios to account for life’s origin and history through strictly mechanistic natural processes. But the facts don’t always match their explanations. The chief example of this is the Cambrian explosion. (For some articles on the problems that this dramatic event in life history creates for the evolutionary paradigm, go here, here, here, and here.)

Known in Darwin’s time, the Cambrian explosion refers to the dramatic appearance of complex animal life in the fossil record about 540 million years ago. Within a short period of time—perhaps less than 5 million years—anywhere from 50 to 80 percent of all animal phyla to ever exist on Earth appeared. The animals that came into existence during the Cambrian explosion were marine creatures. Instead of relatively simple organisms originating at the base of the Cambrian and then evolving toward increased intricacy, complex animals appear suddenly. The traditional evolutionary explanation argues that life should transition from simple to complex in a gradual, branching, tree-like fashion. On the other hand, such explosive appearances are exactly what should be expected if a Creator is responsible for orchestrating life’s history.

Like guilty teenagers confronted with evidence that exposes their explanation, evolutionary biologists try to change their story. This has surely been the case with regard to the Cambrian explosion, as scientists have tried to come up with alternative scenarios to explain away the devastating implications of the Cambrian event for the evolutionary model.

New work published in the journal Current Biology, however, eliminates one of the best counterexplanations that evolutionary biologists have mustered for the Cambrian explosion, making it even less likely that the facts surrounding “biology’s big bang” can be explained away.

The Cambrian Explosion and Darwin

When Darwin wrote On the Origin of Species, he was careful to acknowledge problems with his theory. One of those problems centered on the Cambrian explosion. Darwin wrote:

There is another and allied difficulty, which is much more serious. I allude to the manner in which species belonging to several of the main divisions of the animal kingdom suddenly appear in the lowest known fossiliferous rocks… To the question why we do not find rich fossiliferous deposits belonging to these assumed earliest periods prior to the Cambrian system, I can give no satisfactory answer.

Darwin was referring to the fact that geologists of his time recognized that no fossils of complex animal forms existed in rock formations older than 545 million years. Yet, rocks from the Cambrian time frame (545-485 million years ago) are replete with such remains.

He sidestepped this problem by arguing that the fossil record was incomplete and poorly studied. He expected that as paleontologists collected and analyzed fossils over time, the missing transitional forms and gradual evolutionary transformations would be uncovered. Over the last 150 years, paleontologists have indeed uncovered a treasure trove of fossils that document a rich history of life on Earth.

A Brief Description of Life’s History

The fossil record indicates that prior to about 570 million years ago life on Earth appears to have been dominated by single-celled organisms. At that point an event known as the Avalon Explosion took place. During this origins event, an enigmatic fauna of complex marine creatures known as the Ediacarans appeared. The Ediacaran fauna consisted of about 270 species that have been recovered as fossils in about thirty localities around the world. The organisms disappeared shortly before the Cambrian explosion. New research indicates that Ediacaran fauna emerged explosively, in the same manner as that of the Cambrian event.* During the Avalon explosion the full range of anatomical characteristics displayed by the Ediacarans was already expressed around 570 million years ago. In other words, no evolutionary buildup of biodiversity.

While some of the Ediacaran organisms persist into the Cambrian and a few may have connections to organisms that appear in the Cambrian explosion, most do not. For the most part, the Ediacaran fauna disappears right before the Cambrian explosion.

After the Ediacaran organisms became extinct, the Cambrian explosion took place and represents the first appearance of animal life as we know it today. The last century-and-a-half of research into the fossil record has failed to uncover the missing fossils that Darwin lamented.

A Possible Loop-Hole

While some paleontologists agree that the Cambrian explosion is a real, but enigmatic event—at least enigmatic from an evolutionary vantage point—others argue along Darwin’s famous line. They maintain that the Cambrian explosion is an artifact of an incomplete fossil record. In other words, there is a vast evolutionary history that is invisible because the first, simplest multicellular life-forms weren’t preserved in the fossil record.

To support this appeal to the fossil record’s incompleteness, evolutionary biologists point to trace fossils found in rocks as old as 2.1 billion years in age.

These fossils have been interpreted as tracks produced by complex multicellular animals that were the evolutionary precursors to the organisms that emerged in the Cambrian explosion. These trace fossils are typically characterized as a sinuous groove cut into the ground with a central ridge. The groove is bounded by two lateral ridges. Presumably, these traces were produced by an animal capable of movement that possessed bilateral symmetry

A Surprising New Insight about Trace Fossils

This interpretation, though reasonable, doesn’t appear to be correct based on recent work done by a team of oceanographers and biologists. These scientists were diving near the Little San Salvador Island of the Bahamas and noticed tracks on the ocean floor that were identical to the trace fossils ascribed to the movements of ancient complex animal life thought to have lived well before the Cambrian explosion.

To their surprise, the tracks looked as if they were produced by a large single-celled creature called Gromia sphaerica. The researchers surmised that the tracks resulted from the rolling movement of this organism.

Implications

This find means that the trace fossils in ancient rock formations older than 540 million years were likely not created by complex, multicellular animals, but instead by single-celled organisms like G. sphaerica. This discovery eliminates one of the most compelling counter-explanations that evolutionary biologists give for the validity of the Cambrian explosion. In spite of evolutionary biologists’ story, it looks like the best way to account for the facts associated with the origin of animal life is through the work of a Creator.

*For a discussion of the latest insights into the Avalon explosion see the booklet 10 Breakthroughs of 2008

Previously Posted on May 22nd, 2008 by Fazale ‘Fuz’ Rana, Ph.D.

A sampling of new research uncovers more function for junk DNA, undermines one of the best arguments for biological evolution

My wife enjoys shopping at large club stores. I, however, don’t care for them much. Still, from time to time I’ll join Amy on her shopping excursions, usually enticed by the prospects of free food samples. Nothing’s better than walking up and down store aisles greedily ingesting morsels of tasty food on a late Saturday morning, right before lunch.

Club stores offer free bites of food to let the customers know about all the wonderful products that are available. I’m going to follow suit in this article by offering up a sampling of recent discoveries that ascribe function to junk DNA with the hope that you will have an idea of the remarkable advances happening in molecular biology—advances that are eroding support for one of evolution’s best arguments.

Junk DNA and the Case for Biological Evolution
Evolutionary biologists consider the existence of junk DNA as one of the most potent pieces of evidence for biological evolution. According to this view, junk DNA results when biochemical processes and chemical and physical events transform a functional DNA segment into a useless molecular artifact. Such pieces of DNA remain part of an organism’s genome solely because of its attachment to functional DNA. In this way, junk DNA persists from generation to generation.

Evolutionists also highlight the fact that in many instances identical (or nearly identical) segments of junk DNA appear in a wide range of related organisms. Frequently, the identical junk DNA segments reside in corresponding locations in these genomes. Evolutionists take this to indicate that these organisms shared a common ancestor, suggesting that the junk DNA segment arose prior to the time that the organisms diverged from their shared evolutionary ancestor.

The challenge represented by junk DNA takes on a similar logical form to the problem of evil:

• God is all-good.
• God is all-powerful.
• God is all-knowing.
• Junk DNA exists.

For skeptics and atheists, the last statement is incompatible with the first three. Evolutionists ask, “Why would a Creator purposely introduce nonfunctional, junk DNA at the exact location in the genomes of different, but seemingly related, organisms?”

Responding to the Junk DNA Challenge
Proponents of intelligent design and creationism respond to this valid objection by highlighting the many recent findings that attribute function to junk DNA. Here is a sample of findings that have been reported during the last few months—just to give you a taste.

SINE DNA

This class of junk DNA belongs to a category of sequences known as transposable elements—pieces of DNA that jump around the genome, or transpose. In the process of moving around the genome, some transposable elements make additional copies of themselves, and therefore increase in number when they transpose. SINES belong to a subclass of transposable elements, called retrotransposons. Molecular biologists believe that these DNA elements duplicate and move around the genome through an RNA intermediate and the activity of reverse transcriptase.

SINES range in size from 100 to 300 base pairs (genetic letters). In primates, the most common SINES are the so-called Alu sequences. In fact, there are about 1.1 million Alu copies in the human genome (roughly 12% of the human genome). Alu sequences contain a segment that the cell’s machinery can use to produce an RNA message. In this way, SINES can duplicate and move around the genome as reverse transcriptase back-converts SINE RNA into DNA.

Previous work has identified a functional role for SINE DNA in gene regulation and stress response. (For discussions about SINE DNA function see my books Who Was Adam? and The Cell’s Design.)

New work has now uncovered a role for a newly discovered subclass of SINE DNA in regulating gene expression during brain development in mammals.

Introns

This class of junk DNA consists of DNA sequences that interrupt the coding region of a gene. The DNA sequences that make up genes in eukaryotes consist of stretches of nucleotides that specify the amino acid sequence of a protein (called exons) interrupted by nucleotide sequences that don’t code for anything (called introns). After the gene is copied into a messenger RNA molecule, the intron sequences are excised and the exons spliced together by a protein-RNA complex known as a spliceosome. Because introns interrupt coding sequences of DNA and are excised by the cell’s machinery, many scientists view these elements as junk DNA.

A recent study, however, indicates that introns do serve a function. It appears that some of these sequences help direct messenger RNA to specific locations in the cell.

Once assembled and processed, messenger RNA migrates from the nucleus of the cell into the cytoplasm. At ribosomes, messenger RNA directs the synthesis of proteins. Once produced, the proteins diffuse away from the ribosomes and begin their work for the cell.

Up until now biochemists thought that before exiting the nucleus, where the splicing and other processing reactions take place, all the introns were removed from the RNA message. But new work indicates this is not the case. Researchers discovered a messenger RNA molecule in the cytoplasm of neurons with an intronic sequence.

This messenger RNA molecule harbors a copy of the information needed to produce a protein component of a channel complex that permits the flux of calcium ions across the membranes of the dendrites. This process is essential for nerve transmission. It appears as if this intron helps direct the messenger RNA to the appropriate location in the dendrites where it then directs the production of the proteins that will eventually form the calcium ion channel.

This newly discovered regulatory mechanism may well be a general strategy that helps dictate gene expression in neurons and maybe other cell types as well.

These two advances give a sampling of flavors for the numerous discoveries that have been published in the last few months assigning function to so-called junk DNA. I could continue, but I don’t want to overdo it. After all, consuming too many samples can ruin Saturday’s lunch out.

Next week, I’ll resume the sampling by describing another newly recognized function for a class of junk DNA known as pseudogenes. I hope you’re hungry for more.

Previously Posted on November 12, 2007 by Hugh Ross, Ph.D

One of the cornerstone doctrines of the Christian faith is that humans alone among all life-forms on Earth are sinners. According to the Bible, all humans and only humans are born with the propensity to commit evil acts. That being the case, it should not be difficult for scientists to develop tests to confirm or deny this essential teaching of the Christian faith.

A team of evolutionary biologists at the Max Planck Institute for Evolutionary Anthropology recently performed such a test.¹ The team put chimpanzees in cages where the chimps could withhold food from other chimpanzees by pulling on a rope. The researchers found that the chimpanzees would not withhold food from their compatriots out of pure spite. They would only do so, in a statistically significant manner, in response to a chimp that stole its food.

Interestingly, if a human stole its food and gave it another chimp, there was no significant response toward the chimp that received the food. Also, the team made no attempt to test whether or not chimpanzees would engage in “altruistic punishment” (punishing fellow chimpanzees who stole food from other chimpanzees with whom they had no social contact), though they hinted that they would do so in a future study.

The research team concluded that spiteful behavior appears to be unique to the human species. Only humans will engage in malicious behavior toward their compatriots for no other reason than the fact that they want to hurt someone. The team also commented on humanity’s flip side, namely, that only humans will engage in “pure altruism” (self-sacrificial acts performed to reward or rescue another human being with whom no social context has ever existed or could ever possibly exist). The team thus confirmed the Bible’s repeated commentaries on the state of humanity: uniquely evil among all life on Earth but also uniquely righteous.

1. Keith Jensen, Josep Call, and Michael Tomasello, “Chimpanzees Are Vengeful But Not Spiteful,” Proceedings of the National Academy of Sciences, USA 104 (August 7, 2007): 13046-50.