Never did I imagine when starting this series on Evolution that I would conclude it with a ninth blog! This has been a challenging series that likely reflects my background as a geologist/geochemist rather than a biologist! I’ll begin with a summary of each lesson:
Lesson 1 – General overview; introduction and discussion of micro- vs. macro-evolution.
Lesson 2 –Introduces and discusses the “proofs” (or the “pros”) of evolution that were presented to us (geology students) at Texas A&M during the 1970’s. Also included is a list of current “cons” (50 years later). The first proof, “microevolution” is discussed. It addresses mutation rates (extremely slow for complex animals) vs. the fossil record which suggests faster “bursts” of change. “Homologies” (similar structures in different animals that serve different purposes) are also discussed.
Lesson 3 – The next “proof”—embryonic similarity—is discussed. The similarity of embryos among various animal types was initially proposed as evidence of evolution during the early 1870’s. It too was presented at A&M. Several of the early drawings were eventually discovered to be frauds.
Lesson 4 – This lesson discusses the “origin” of life itself and, “How did it all begin?” It addresses the enormous challenge of abiotic assemblage of a single protein and concludes with Stanley Miller’s experiment to demonstrate that the individual components of a protein (amino acids) form naturally.
Lesson 5 – Another aspect of the “origins” issue—cellular structure and irreducible complexity are discussed. A DVD was presented of an early conference between several biochemists that proposed a different mechanism for the “origins” dilemma—”Intelligent Design.”
Lesson 6 – This lesson introduces geologic basins, sediment, and the earliest fossilized evidence of life. Bacteria (possibly Cyanobacteria, or “blue-green algae”) seem to have occurred almost instantaneously after the early earth and its oceans stabilized. Graphite (carbon) residues in the earliest rocks bear the carbon isotope ratio evident of living organisms.
Lesson 7 – The progressive change in life forms proposed by Darwin was difficult to discern over the next 3.5 By. Single-cell Cyanobacteria and algae were evident until about 0.65 Bya. The Vendian Period began at that point, with the first evidence of multicellular creatures. Known as the Ediacaran fauna, their dissimilarity to modern life forms as well as their mass extinction about 0.540 Bya (or 540 million years ago—Mya) are discussed.
Lesson 8 – This lesson introduces the Cambrian Explosion of life that occurred ~540 Mya. Several phyla of complex animals (with bilateral symmetry), many with traits that are present in species today, suddenly appear in the fossil record in what may be less than 500,000 years. The Bible (Genesis 1:20-23) states that God simply spoke (“bara”) all the sea creatures into existence.
Hopefully, this brief review of the previous blogs ties together several components of this complex topic. I suspect that evolutionary biologists would take exception to several points and claim that the biological evidence and trends were grossly oversimplified – and I’m sure they were. I’m not a biologist.
The next two sections summarize my stand on macroevolution. First, why the technical data that I’m familiar with seems to speak against the process; and, secondly, my subsequent dilemma as a Christian.
Macroevolution: My Conviction From the Data
The perplexing twists and turns of evolutionary theory cover a broad range. Charles Darwin expressed several concerns regarding his theory. The lack of advanced fossils that pre-dated the Cambrian troubled him, as did the relatively short time interval, as understood in the late 1800’s, for life to evolve. Today, we recognize a relatively complete sequence of progressively advanced life forms that eventually lead to modern man. But does progression reflect the slow, evolutionary change that Darwin envisioned?
Two data points dominate my opinion on a macroevolutionary origin. These include the lengthy mutation rates reported for the evolutionary change of complex animals, and in contrast, the sudden appearance over a very brief time interval of multiple phyla of complex animals during the Cambrian explosion. I’ll review and summarize each:
Mutation Rates. In Part 2 of this Evolution series (Blog #26), I shared a technical article that summarized the mutation rates for various organisms. Specifically, I addressed how the frequent introduction and transmittal of new COVID-19 variants reflect the rapid mutation rate of a virus—about 10-2.5 or about one mutation every 330 replications. In contrast, the mutation rate of a mouse is about 10-10.5 or about eight orders of magnitude slower. I also shared another study that identified genetic differences between organisms. About a 15% difference exists in the genes between a chimpanzee and a human. Biologists estimate that even a very generous mutation rate of 10-9 would still require over 10 million years for only a 1% change in the genome (the complete DNA package) of the organism.
Duration of Cambrian Explosion. Part 8 of this Evolution series (Blog #32) addressed the duration of the “Explosion Interval” (the time between the disappearance of the Ediacaran fauna and the appearance of new, complex animals of the Cambrian period). The original estimate of the time interval has progressively decreased with the discovery of new localities that expose the Cambrian/Pre-Cambrian boundary. The interval has decreased from 18 My in the mid-1980’s to less than 410,000 years in very recent discoveries in Namibia (Africa; 2019). Less than 410,000 years passed between the disappearance (extinction) of relatively simple organisms from the Vendian Ediacaran assemblage to the appearance of complex, bilaterally symmetric organisms in the earliest Cambrian strata.
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Hopefully, my doubts regarding macroevolution are discernible from the preceding subsections. At least 10 million years are reportedly required for a 1% change in the DNA genome of a small mammal, and yet, no more than 410,000 years appear to have passed before the introduction of numerous phyla of complex organisms during the Cambrian Explosion.
How did they arise/evolve so quickly, if indeed they did? What do evolutionary biologists say?
Today’s biologists believe that “Evolutionary Radiation” was responsible for the rapid bursts of new animals and phyla. It assumes that a precursor, or ancestral organism is available when an environmental niche (or some other advantage) develops that favors the organism. It allows the organism to rapidly speciate and fill the niche.1 In the case of the Cambrian Explosion, biologists speculate that one or more, perhaps several ancestors were present. These were soft-bodied (i.e., did not produce a fossilized remnant). These ancestors then radiated into the Early Cambrian setting, and thereafter, developed shells or exoskeletons that could fossilize and be found today. Here’s an example from a recent publication:2
The earliest trilobite fossils are about 530 million years old, but the class was already quite diverse and cosmopolitan, suggesting they had been around for quite some time. The fossil record of trilobites began with the appearance of trilobites with mineral exoskeletons – not from the time of their origin.
As I’ve stated several times during this series, “I’m not a biologist.” But from my perspective, this example perfectly portrays the transcendent views that persist throughout the biological sciences:
- Macroevolution is a fact,
- There is no debate about “if” it occurred,
- And yet, the confirmatory, fossil evidence of the ancestral organisms has yet to be discovered.
Or, in other words, “We know evolution occurred, and they (the fossilized remnants to prove it) are out there—we just haven’t found them yet!”
Darwin was the first to legitimately propose this explanation of undiscovered fossils in 1872, stating that only a small fraction of the earth is known with accuracy. We (the Texas A&M geology students) were hammered with it in the mid-1970s. And here it is again, in 2023, only 150 years later. We know the earth well at this point.
Are they (the ancestral fossils) out there? Perhaps. . . or not. It’s hard to prove a negative.
Macroevolution: My Struggle Based Upon Christian Supporters
But perhaps this inability to resolve the conflict also reflects my dilemma with the topic.
Everything I see as a geologist/geochemist suggests immediate extinctions and explosive appearances of more advanced organisms. This beautifully agrees with Psalm 104:24-30, “He makes them (earth’s animals) return to dust, He creates them anew, and restores the face of the earth (JRC paraphrase). Also, the Cambrian Explosion seems to be a beautiful example of God “speaking into existence (barah)” all the “swarming sea creatures” on Day 5 (Genesis 1:20-23). Furthermore, the 410,000-year Explosion interval as measured in the Namibia strata seems impossible to reconcile with our understanding of the current mutation rates of advanced organisms.
And yet, here I sit in a perplexing dilemma. . . Why?
It’s because of my Christian brothers and sisters who are biologists (some with advanced degrees) and who remain strong advocates of evolution.
I’ve fought many battles and endured too many debates with my Young Earth brethren. I’ve insisted that they evaluate and incorporate the Truth expressed in God’s creation with Truth expressed in Scripture. The progression of life (from simple to complex) is obvious in the fossil record. So, how can I ignore my brethren and sister biologists when they glorify God through this marvelous progression of life that they acknowledge as evolution? What do they see that so encourages them to integrate this progression into a 3.5-billion-year continuous event, and not be dissuaded by what others consider “extinctions and explosive appearances?”
Or, perhaps more importantly, what am I missing?
And finally, if you believe that those Christians who support evolution are doing so in a “simple-minded” manner with no legitimate scientific or Scriptural basis, consider the “BioLogos” website (the name itself portrays legitimacy). It’s webpage simply states, “God’s Word, God’s World.” Do some research on its founder, Francis Collins, and his credentials. Just visit the following link. I dare you!
Perhaps you will then appreciate my dilemma:
1Wikipedia: Evolution Radiation; https://en.wikipedia.org/wiki/Evolutionary_radiation
2Wikipedia: Cambrian Explosion; https://en.wikipedia.org/wiki/Cambrian_explosion