Conservation Biology Studies Elicit Doubts about the First Human Population Size



Adam named his wife Eve, because she would become the mother of all the living.

–Genesis 3:20

Prior to joining Reasons to Believe in June of 1999, I spent seven years working in research and development for a Fortune 500 company. Part of my responsibilities included method development. My lab worked on developing analytical methods to measure the active ingredients in our products. But more interesting to me was the work we did designing methods to predict consumer responses to our product prototypes.

Before we could deploy either type of method, it was critical for us to ensure that the techniques we developed would generate reliable, accurate data that could be used to make sound business decisions.

Method Validation

Researchers assess the soundness of scientific methods through a process called method validation. A key part of this process involves applying the method to “known” samples. If the method produces the expected result, it passes the test. For example, the team in my lab would often develop analytical methods to measure the active ingredients in our products. To validate these methods, we would carefully weigh and add specified amounts of the actives to prepared samples and then use our newly developed method to measure the ingredient levels. If we got the right results, it gave us the confidence to apply the method to real world samples.

A Controversy about the Size of the First Human Population

Currently, a set of scientific methods resides at the center of an important controversy among conservative and evangelical Christians about the historicity of Adam and Eve. Specifically, the scientific methods in question are designed to measure the population size of the first humans. Even though the traditional reading of the biblical creation accounts indicates humanity began as a primordial pair—an Adam and Eve—all three sets of methods indicate that the initial human population size consisted of several thousand individuals, not two, raising serious questions about the traditional Christian understanding of humanity’s origin. Some evangelical Christians argue that we must accept these findings and reinterpret the biblical creation accounts, regardless of the theological consequences. Others (myself included) question the validity of these methods. It is important to make sure that these techniques perform as intended before abandoning the traditional biblical view of humanity’s beginnings.

The Importance of Adam and Eve’s Historicity

The finding that humanity began as a population, not a pair, causes quite a bit of consternation for me and many other evangelical and conservative Christians. Adam and Eve’s existence and role as humanity’s founding couple are not merely academic concerns. For the Christian faith, the question of Adam and Eve’s historicity are more significant than any business decision that relied on analytical methods my lab developed. (Data from my lab was used to make some decisions that involved millions of dollars.) The historicity of Adam and Eve impacts key doctrines of the Christian faith, such as inerrancy, the image of God, the fall, original sin, marriage, and the atonement.

Again, given the profound implications of abandoning Adam and Eve’s historicity, it is important to know if these population size methods perform as intended. They are a big part of the reason evolutionary biologists and geneticists reject Adam and Eve’s existence. To put it another way, are these methods valid, yielding accurate, reliable results?

Measuring the Initial Human Population Size

Currently, geneticists use three approaches to estimate the size of the initial human population. 1

  1. The most prominent method finds its basis in mathematical expressions relating the current genetic variability among humans today to mutation rate and initial population size. Using these relationships, geneticists develop mathematical models that allow them to calculate the initial population size for the first humans after measuring genetic variability of contemporary human population groups (and assuming a constant mutation rate).
  2. A more recently developed approach relies on a phenomenon called linkage disequilibrium to measure the initial population size of the first humans.
  3. The final approach (also relatively new on the scene) makes use of a process called incomplete lineage sorting to estimate humanity’ s initial population size.

Are Population Size Methods Valid?

So are these methods valid? When I have asked evolutionary creationists this question, they usually hem and haw, and then reply: These methods are based on sound, well-understood phenomena, and therefore should be considered reliable.

I believe that to be true. The methods do appear to be based on sound principles. But that is not enough—not if we are to draw rigorous scientific conclusions. Scientific methods can only be considered reliable if they have been validated. When I worked in R&D, if I insisted to my bosses that they should accept the results of methods I developed because they were based on sound principles but lacked validation data, I would have been fired.

So given the importance of the historical Adam and Eve, why should we accept anything less for population size measurements?

To my surprise, when I survey the scientific literature, I can’t find any studies that demonstrate successful validation of any of these three population size methods. For me, this is a monumental concern, particularly given the importance of Adam and Eve’s historicity. The fact that these methods haven’t been validated provides justification for Christians to hold the results of these studies at arm’s length.

In fact, when it comes to the first category of methods, I find something even more troubling: Studies in conservation biology raise serious questions about the validity of these methods. Of course, we can’t directly validate methods designed to measure the numbers of the first humans because we don’t have access to that initial population. But we can gain insight into the validity of these methods by turning to work in conservation biology. When a species is on the verge of extinction, conservationists often know the numbers of species that remain. And because genetic variability is critical for their recovery and survival, conservation biologists monitor genetic diversity of endangered species. In other words, conservation biologists have the means to validate population size methods that rely on genetic diversity.

In my book Who Was Adam? I discuss three separate studies (involving mouflon sheep, Przewalski’s horses, and gray whales) in which the initial populations were known. When the researchers measured the genetic diversity generations after the initial populations were established, the genetic diversity was much greater than expected—again, based on the models relating genetic diversity and population size.2 In other words, this method failed validation in each of these cases. If researchers used the genetic variability to estimate original population sizes, the sizes would have measured larger than they actually were.

In Who Was Adam? I also cite studies that raise doubts about the reliability of linkage disequilibrium methods to accurately measure population sizes.3 Not only is this method not validated, it, too, has failed validation.

Recently, I conducted another survey of the scientific literature to see if I had missed any important studies involving population size and genetic diversity. Again, I was unable to find any studies that demonstrated the validity of any of the three approaches used to measure population size. Instead, I found three more studies indicating that when genetic diversity was measured for animal populations on the verge of extinction it was much greater than expected, based on the predictions derived from the mathematical models.4

The Surprisingly High Genetic Diversity of White-Tailed Deer in Finland

Of specific interest is a study published in 2012 by researchers from Finland. These scientists monitored the genetic diversity (focusing on 14 locations in the genome consisting of microsatellite DNA) of a population of white-tailed deer that were introduced into Finland from North America in 1934.5 The initial population consisted of three females and one male, and since then has grown to between 40,000 to 50,000 individuals. This population has remained isolated from all other deer populations since its introduction.

Though the researchers found that the genetic diversity of this population was lower than for a comparable population in Oklahoma (reflecting the genetic bottleneck that occurred when the original members of the population were relocated), it was still surprisingly high. Because of this unexpectedly high genetic diversity, size estimates for the initial population would be much greater than four individuals. To put it another way, this population size method fails validation—one more time.

Why is this approach to measuring population sizes so beleaguered, when the method is based on sound, well-understood principles? In Who Was Adam? (and elsewhere), I point out that the equations undergirding this method are simplified, idealized mathematical relationships that do not take into account several relevant factors that are difficult to mathematically model, such as population dynamics through time and across geography.

Recently, conservation biologists have identified another factor influencing genetic diversity that confounds the straightforward application of the equations used to calculate initial population size: long generation times. That is, animals with long generation times display greater-than-anticipated genetic diversity, even when the population begins with a limited number of individuals.6

This finding is significant when it comes to discussions about Adam and Eve’s historicity. Human beings have long generation times—longer than white-tailed deer. From a creation model perspective, these long generation times help to explain why humanity displays such relatively large genetic diversity, even though we come from a primordial pair. And it suggests that the initial population size estimates for modern humans are likely exaggerated.

So did humanity originate as a population or a primordial pair?

The claims of some geneticists and evolutionary biologists notwithstanding, it’s hard to maintain that humanity began as a population of thousands of individuals, because the methods used to generate these numbers haven’t been validated—in fact, work in conservation biology makes me wonder if these methods are trustworthy at all. Given their track record, I would never have used these methods when I worked in R&D to make a business decision.



  1. For a recent and accessible discussion of these methods see Dennis R. Venema and Scot McKnight, Adam and the Genome: Reading Scripture after Genetic Science (Grand Rapids, MI: Brazos Press, 2017), 45–48.
  2. Fazale Rana with Hugh Ross, Who Was Adam? A Creation Model Approach to the Origin of Humanity (Covina, CA: RTB Press, 2015), 349–353.
  3. Ibid.
  4. Catherine Lippé, Pierre Dumont, and Louis Bernatchez, “High Genetic Diversity and No Inbreeding in the Endangered Copper Redhorse, Moxostoma hubbsi (Catostomidae, Pisces): The Positive Sides of a Long Generation Time,” Molecular Ecology 15 (June 2006): 1769–1780, doi:10.1111/j.1365-294X.2006.02902.x; Frank Hailer et al., “Bottlenecked But Long-Lived: High Genetic Diversity Retained in White-Tailed Eagles upon Recovery from Population Decline,” Biology Letters 2 (June 2006): 316–319, doi:10.1098/rsbl.2006.0453; Jaana Kekkonen, Mikael Wikström, and Jon E. Brommer, “Heterozygosity in an Isolated Population of a Large Mammal Founded by Four Individuals Is Predicted by an Individual-Based Genetic Model,” PLoS ONE 7 (September 2012): e43482, doi:10.1371/journal.pone.0043482.
  5. Kekkonen, Wikström, and Brommer, “Heterozygosity in an Isolated Population.”
  6. Lippé, Dumont, and Bernatchez, “High Genetic Diversity and No Inbreeding”; Hailer et al., “Bottlenecked but Long-Lived.”
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Does Radiocarbon Dating Prove a Young Earth? A Response to Vernon R. Cupps



In my experience, one of the most persuasive scientific claims for a young Earth is the detection of carbon-14 in geological samples such as coal and fossilized dinosaur remains.1According to young-earth creationists (YECs), if the coal samples and fossils are truly millions of years old (as the scientific community claims), then there shouldn’t be any trace of carbon-14 in these samples. Why? It’s because the half-life of carbon-14 is about 5,700 years, meaning that all the detectable carbon-14 should have disappeared from the samples long before they reach even 100,000 years of age.

In Dinosaur Blood and the Age of the Earth, I respond to this young-earth argument, suggesting three mechanisms that can account for carbon-14 in fossil remains (and by extension, in geological materials) from an old-earth perspective.

When YECs detect carbon-14, they find it at low levels, corresponding to age dates older than 30,000 years (not 3,000 to 6,000 years old, as their model predicts, by the way). These low levels make it reasonable to think that some of the carbon-14 signal comes from contamination of the sample by, say, microorganisms picked up from the environment.

These low levels also make it conceivable that some of the detected carbon-14 is due to a ubiquitous carbon-14 background. Cosmic rays are continuously producing radiocarbon from nitrogen-14. Because of this nonstop production, carbon-14 is everywhere and will show up at extremely low levels in any measurement that is made, even if it isn’t present in the actual sample.

It is also possible that some of the carbon-14 in the fossil and coal samples arises from the in situ conversion of nitrogen-14 to carbon-14 driven by the decay of radioactive elements in the environment. Because fossils and coal derive from once-living organisms, there will be plenty of nitrogen-14 contained in these specimens. For example, environmental uranium and thorium would readily infuse into the interiors of fossils, and as these elements decay, the high energy they release will convert nitrogen-14 to carbon-14.

Employing a “back-of-the-envelope” flux analysis, Vernon Cupps—a YEC affiliated with the Institute of Creation Research—has challenged my assessment, concluding that neither (1) the production of carbon-14 from cosmic radiation nor (2) the decay of radioactive isotopes in the environment is sufficient to account for the carbon-14 detected in fossil and geological samples.2

Though I think his analysis may be unrealistically simplistic, let’s assume Cupps’s calculations are correct. He still misses my point. In Dinosaur Blood and the Age of the Earth, I argue that all three possible sources simultaneously contribute to the detectable carbon-14. In other words, while no single source may fully account for the detectable carbon-14, when combined, all three can. Cupps’s analysis neglects the contribution of the ubiquitous background carbon-14 and possible sources of contamination from the environment.

Ironically, the low levels of carbon-14 detected in fossils and geological specimens by YECs actually argue against a young Earth, not an old Earth.

How can that be?

If fossil and geological specimens are between 3,000 and 6,000 years old, then somewhere between 50 and 75 percent of the original carbon-14 should remain in the sample. This amount of material should generate a strong carbon-14 signal. The fact that these specimens all age-date to 30,000 to 45,000 years old means that less than 2 percent of the original carbon-14 remains in these samples—if the results of this measurement are taken at face value. It becomes difficult to explain this result if these samples are less than 6,000 years old. On the other hand, the weak carbon-14 signal measured by YECs does make sense if carbon-14 does not reflect the material originally in the sample, but instead stems from a combination of (1) contamination from the environment, (2) ubiquitous background radiocarbon, and/or (3) irradiation of the samples by isotopes such as uranium or thorium in the environment.

To put it plainly, it is difficult to reconcile the carbon-14 measurements made by YECs with fossil and geological samples that are 3,000 to 6,000 years old, Cupps’s analysis notwithstanding.

On the other hand, an old-earth perspective has the explanatory power to account for the low levels of carbon-14 associated with fossils and other geological samples.



  1. Vernon R. Cupps, “Radiocarbon Dating Can’t Prove an Old Earth,” Acts & Facts, April 2017,
  2. Ibid.
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Can Science Detect the Creator’s Fingerprints in Nature?



Which of these does not know that the hand of the Lord has done this?

Job 12:9

In early March (2017), I took part in a forum at Samford University (Birmingham, AL), entitled Genesis and Evolution. At this two-day event, the panelists presented and discussed scientific and biblical perspectives on Young-Earth, Old-Earth, and Evolutionary versions of creationism.

The organizers charged me with the responsibility of describing Old-Earth Creationism (OEC) from a scientific vantage point, while also providing the rational for my views.

As part of my presentation, the organizers asked me to discuss the assumptions that undergird my views. One of the foundational tenets of OEC is an important idea taught in Scripture: God has revealed Himself to us through the record of nature. According to passages such as Job 12: 7-9, part of that revelation includes the ‘fingerprints’ He has left on His creation.

If Scripture is true, then scientific investigation should uncover evidence for design throughout the natural realm. Science should find God’s fingerprints. And, indeed, it has. As a biochemist, I am deeply impressed with the elegance, sophistication, and ingenuity of the cell’s molecular systems. In my view, these features reflect the work of a mind—a Divine Mind. But, the evidence for intelligent design in the biochemical realm is much more extensive. For example, the eerie similarity between the structure and function of biochemical systems, and the objects and devices produced by human designers further evinces the Creator’s handiwork. In my book The Cell’s Design, I show how the remarkable similarities serve to revitalize William Paley’s Watchmaker Argument for God’s existence.

To describe the hallmark features of human designs, Paley used the term contrivance. Human designs are contrivances. And so, are biological systems. If human contrivances require the work of human designers, then, it follows that biological systems—which, too, are contrivances—require a Divine designer. In The Cell’s Design, I introduce the concept of an intelligent design pattern. Following Paley, I identify several features that characterize human designs. Collectively, these characteristics form a pattern that can then be matched to the features of biological and biochemical systems. The greater the match between the intelligent design pattern and biological/biochemical systems, the greater the certainty that designs found in living systems are the work of a mind.

In response to my presentation at the Genesis and Evolution event, cell biologist Ken Millerfrom Brown University—a well-known critic of intelligent design—argued that creationism and intelligent design cannot be part of the construct of science, because science lacks the capability of detecting the supernatural. In his book, The Triumph of Evolution and the Failure of Creationism, paleontologist Niles Eldredge makes this very point:

“We humans can directly experience the material world only through our senses, and there is no way we can directly experience the supernatural. Thus, in the enterprise that is science, it isn’t an ontological claim that a God does not exist, but rather an epistemological recognition that even if such a God did exist, there would be no way to experience that God given the impressive, but still limited, means afforded by science. And that is true by definition.”1

But, as I pointed out during my presentation and elsewhere there are scientific disciplines predicated on science’s capacity to detect the activity of intelligent agency. One is SETI: The Search for Extraterrestrial Intelligence. Astronomers involved in this research program seek ways to distinguish between electromagnetic radiation emanating from astronomical objects from those hypothetically generated by intelligent agents that are part of alien civilizations. To put it another way, SETI is an intelligent design research program.

Research by scientists from the Harvard-Smithsonian Center for Astrophysics powerfully illustrates this point.2 These investigators propose that fast radio burst (FRBs) emanate from alien technology, specifically planet-sized transmitters powering interstellar probes.

Astronomers discovered FRBs in 2007. Since then, around two dozen exceedingly bright, millisecond bursts of radio emissions have been detected. Astronomers think that FRBs originate in distant galaxies, billions of light years away.

The Harvard-Smithsonian scientists calculate that the transmitters could generate enough energy from sunlight to move probes through space, if the light was directed to onto structures twice the size of Earth. Given the energies involved, the transmitters would have to be cooled. Again, the researchers estimate that a water-cooled device twice Earth’s size could keep the transmitter from melting.

The researchers recognize that construction of the transmitters lays beyond our technology, but is possible given the laws of physics. They speculate aliens built these transmitter to power light sails to move space craft, weighing a million tons and carrying living creatures across interstellar space.

These astronomers maintain that the transmitter would have to continually focus its beam on the light sails. FRBs originate when the transmitter and light sails briefly point in Earth’s direction due to the relative motion of the transmitter and light sail.

So, are FRBs evidence for alien technology? Avi Loeb, one of the Harvard-Smithsonian scientists, admits that their proposal is speculative, but justifies it because, “we haven’t identified a possible natural source with any confidence.”3 But, Loeb argues, “Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge.”4

So, contrary to the protests of scientists, such as Miller and Eldredge, science does have the tool kit to detect the handiwork of intelligent agents and even discern the capabilities and motives of the intelligent designer(s). So, why not let intelligent design proponents and creationists put their ideas out there and let the data be the judge?

It is interesting that the Harvard-Smithsonian astronomers think they can recognize the work of intelligent designers who possess capabilities beyond what we can understand—and, maybe, even imagine. They also think that they can discern the purpose behind the alien technology—space exploration. So why can’t science recognize the work of a Creator whose capabilities exist beyond what we can imagine?

So, considering the proposal by the Harvard-Smithsonian investigators, it is disingenuous for Miller, Eldredge, and other scientists, to reject, out of hand, the claim the scientific evidence for God’s fingerprints in biochemical systems. I contend that the intelligent design pattern that I describe in The Cell’s Design can be used to rigorously—and, even, quantitatively—characterize the Creator’s activity in biological systems. Moreover, as I have discussed previously, science has the tools to identify the designer.

As the apostle Paul wrote, evidence for the Creator is “clearly seen from what has been made.” (Romans 1:20) If only the scientific community would be willing to look.


Fast Radio Bursts: E. T. Is Not Calling Home by Hugh Ross (article)

Fast Radio Bursts Update by Hugh Ross (article)

A Biochemical Watch Found in a Cellular Heath by Fazale Rana (article)

Can Science Identify the Intelligent Designer? by Fazale Rana (article)

The Cell’s Design By Fazale Rana (book)


  1. Niles Eldredge, The Triumph of Evolution and the Failure of Creationism (New York: Holt and Company, 200) p. 13.
  2. Harvard-Smithsonian Center for Astrophysics, “Could Fast Radio Burst Be Powering Alien Probes?” ScienceDaily (March 9, 2017),
  3. Harvard-Smithsonian Center for Astrophysics, “Could Fast Radio Burst Be Powering Alien Probes?” ScienceDaily (March 9, 2017),
  4. Harvard-Smithsonian Center for Astrophysics, “Could Fast Radio Burst Be Powering Alien Probes?” ScienceDaily (March 9, 2017),
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