My 130th Great Grandpa
Engarde Glen! Even though we are both considered creationists, you believe in an old earth-life model, 3-4 billion years old, and that God used evolution to bring about life on this planet (theistic evolution). Balderdash! I am going to take the position of the young earth-life model (even though I remain open) that started with Adam and Eve and challenge you to a duel. I will show that the human population started with one Common Ancestory who was Adam and Eve about 6-7 thousand years ago. Homo Sapiens did not evolve from other primates over the period of 300,000 years. Homo Erectus, Neanderthals, Denisovans, etc. are just our cousins. I could start with a number of topics, but let me start by throwing you a softball. Let’s start with demography, or the study of the human population.
Were Adam and Eve the parents of the human family? Is it possible from demographic analysis to show that one couple could populate 9 billion people, like the bible says it did; especially with the flood resetting the start of human population? Is 4,500 years enough time to produce the current human population? This article will explore this topic and show that not only is it possible, but scientifically more probable than some old earth-life evolutionary beliefs.
The Science and Religion
Ancient Human population estimates that are greater than 3,000 BC, come from archaeology and are very speculative at best. Some traditional scientists believe that the human population was a flat line of around a million people for about 300,000 years up to when farming and the domestication of animals started, around 8,000 BC. From here it took off more exponentially according to natural growth predictions.
Recently, this traditional view has been heavily questioned as more data is analyzed. One such area is demographic analysis of the human population. All things in nature grow exponentially. More and more scientists are asking, “does farming really answer why the human population putters around at a million people for 300 millenia and then suddenly takes off? Why should human population growth be an exception to the rest of nature?”
Natural growth is typically characterized by the following general form of an exponential equation:
n = eλt
where n is the population number,
e is the Euler number, or base for natural logarithms,
λ is the growth rate, and
t is the time.
Bacteria growth, bunny rabbit growth, and human population growth all behave according to this basic stochastic exponential function. The real trick is in knowing the growth rate. For the human population, wars, plagues, environmental conditions, social-economical conditions, and religious beliefs – to name a few, all affect the growth rate. In spite of these, the population growth for most living things is exponential; not flat lined for long periods.
For our purposes we can derive a special form of the equation that includes the number of children and parental lifespans. I’ll spare the math in this article, but you can dig deeper by consulting several sources 1.
Pn = 2 (c(n-x + 1)) (cx - 1) / (c-1)
where Pn is the total population,
c is ½ the number of children born (or fertile females),
n is the number of generations, and,
x is the span of generations that parents live.
Based on this formula we can perform some demographic analysis of the human population of the earth. So, let's try it out. Let’s take a biblical view and see if human life starting 6,000 years ago and has a rational fit. For the variables let’s assume that there are approximately 3 generations every century, or n = 180 (3 * 6,000 / 100). Assume that each generation produces 2.255 kids per family, which is a reasonable average taking into account non-fertility and other calamities, and that the parents live for 2 generations, or about 66 years (c = 1.128, x=2). Cranking through the equation gives a population of a little over 9 billion people, which is about the current earth population today. For a large number of generations, the lifespan, x, has little effect. However the number of kids (2c) is very sensitive. The table below shows Pn with different values for c.
As “c” approaches “1”, there is no population growth. As “c” approaches 1.128, the population grows to over 9 billion in 180 generations.
Note that this formula has several shortcomings and is an approximation at best. It assumes that every “c” reproduces, which of course isn’t the case. Some females die before child bearing. Others choose not to have children or are unable.
This brings up the concept of population replacement birth rate, which in demographic analysis accounts for the actual death rate, and is accounted for in the equation by both variables “x” and “c”. The birth rate can roughly be thought of as 2c in our equation. The replacement rate today averages 2.3 live births per woman for developing regions and 2.1 for most industrialized countries. Contrast this with the average number of US children being born per family in 1800, which was “7” (c=3.5). This ordinarily would give a huge spike in population growth, however, it is important to point out that previous to the 19th century more children were born, but many didn’t live old enough to reproduce.
While archaeology is the only way to estimate ancient populations, more recent estimates include written records and demographic analysis. The earliest known written population records come from Sumerian city-states such as Uruk, Ur, and Lagash (3,000-2,500 BC). Under the Ur III dynasty (c. 2,100 BC), there are especially detailed administrative tablets listing laborers, families, and economic outputs. These are the earliest surviving written demographic-style records. Ancient Egypt conducted periodic counts for taxation and labor drafts, known as the “cattle count”, as early as the Old Kingdom (c. 2,600 BC). In China early household counts likely occurred under the Shang dynasty (c. 1600–1046 BC), but the first fully preserved large-scale census came later in 2 AD. This is the earliest surviving nationwide census with population totals.
Left, cuneiform clay tablet population record (c. 3,000-2,500 BC). Middle, ancient Egyptian cattle count (c. 2,600 BC). Right, ancient Chinese household counts (c. 1,600–1,046 BC).
The Hebrew Bible lists generations of families (c. 4,000-0 BC), and censuses in the Book of Numbers and during King David’s reign (c. 1,200–500 BC). These were primarily for military conscription and tribal organization. While theological in presentation, they reflect early demographic enumeration practices. The Roman Republic and later the Roman Empire conducted regular censuses beginning around 500 BC.
Modern demographic analysis began with John Graunt's (1,629–74) rudimentary Life Table. All of these records serve to give data points for human population demographic analysis.
So now let’s combine archaeological data, written records, and demographic analysis to come up with a few data points, and plot these into a chart. Again we will use the bible as our timeline.
Taking into account all of these variables (number of generations, life span, death rate, wars, disease, etc.) the population growth for humans can nicely fit a 6,000 year span as shown in the chart below.
The Summary
By plugging in the best known data, conservative demographic analysis supports a relatively short human population timeline. This is even taking into account a flood that basically resets it to almost 4,500 years. Best accounts give 114 generations from the flood (n=114) to now, and to reach 9 billion people you would need an approximate average birth rate of 2.275 (C=1.138, X=2). This is very reasonable. In fact, demographic analysis does not support a 10,000 year timeline (n=300, X=2, C=1.075); let alone one that is 300,000 years. The birth rates would be too small to support scientific archaeology and historical records.
Many assumptions of evolution are being questioned with today's scientific data and methods. The evolution and age of humans is one. Demography points toward a much shorter growth timeline than predicted by old traditional evolution. 300,000 years is not natural! Stay tuned for more discussions on what “is” and “isn’t” true about evolution.
Henry M. Morris, The Biblical Basis for Modern Science, Part 4, Chapter 15. Baker Books, Grand Rapids, Michigan, 1984
Colin McEvedy and Richard Jones, 1978, Atlas of World Population History, Facts on File, New York, ISBN 0-7139-1031-3.
Hyde, 202010, Colin McEvedy and Richard Jones, 1978, Atlas of World Population History, Facts on File, New York, ISBN 0-7139-1031-3.
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