Re: [asa] Millions of years population growth

Some excellent replies here, but here's a much more in-depth rebuttal from
talkorigins.org:
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*Young-earth "proof" #25:* The current population of Earth (5.5 billion)
could easily be generated from 8 people in less than 4000 years. If the
earth were really billions of years old, the human population would have
gone through the roof!

*25.* Yes, and by the same reasoning 8 germs could populate every cubic inch
of available living space on Earth to the tune of 1 million strong in less
than a week! That is, if we allow for a generous die-off rate such that the
fourth generation has about 40 germs instead of 128, and if we assume that
the population divides every hour, each and every cubic inch of living space
on the earth (from 100 feet below ground to a mile above) would have 1
million germs after 158 generations. I guess, by creationist reckoning, the
earth must be a week old! If it were a few thousand years old, the germ
population would have gone through the roof!

Yes, given unlimited living space, an inexhaustible supply of food, a good
deal of luck in the early stages, and a high motivation to travel while
having more kids than is practical, eight people

could probably populate the earth in a few thousand years. Eight germs could
do it in less than a week. Eight bunny rabbits would fall somewhere in
between. Eight cats would give us yet another figure. What do any of these
figures have to do with the age of the earth? Nothing! What do these figures
have to do with actual growth rates? Absolutely nothing!

The human exponential growth rate of the last few hundred years is possible
only because of technology. When our ability to stay one jump ahead of
starvation and disease fails, when our resources are finally squandered,
then you'll see a dramatic change in that growth rate! It will no longer be
exponential; it will be disastrous!

When man lived in scattered tribal groups, which is what he did for 99% of
his history, the net human population growth was zero most of the time, just
as it is for animals today. Animal populations, especially small animals
such as rabbits or mice, often undergo cycles of boom and bust but their net
growth is zero. No permanent increase in population can be sustained unless
it is supported by a permanent change in the environment. Such a change
might include the loss of a predator due to the colonization of new
territory, a permanent increase in the food supply due to climatic change or
a change in dietary habits, or a variety of other factors. In the case of
man, hunting technology, the development of agriculture, and the use of
fossil fuels have played major roles. After a favorable change in the
environment, a population of animals (or people) may record a permanent jump
before leveling off at a zero net growth again. Thus, the growth rate,
before technology intervened in a major way, necessarily involved a series
of plateaus where the population was in approximate equilibrium with the
environment. No doubt, many tribal groups died out. Anthropologists can cite
several examples of early human or near-human species, side branches on our
evolutionary tree, which left no descendants. There was no assurance that
early man would even survive. When favorable changes did occur, large jumps
between plateau levels would likely have been exponential. Indeed, the human
exponential growth rate of the last 300 years or so can be thought of as one
long jump to a new plateau, which has been raised artificially high by
technology. Those who imagine that eight people gave rise to everyone living
today according to a simple exponential growth curve have demonstrated an
inability to think things through. Let's look at the equation involved in
these growth rate calculations.

P(n) = P(1 + r)n

*P(n)*, called the function *P* of *n*, is the population generated after *n
* years. (With the proper adjustment of *r*, n could be months or
generations, etc. For our purposes, years will do nicely and *r* will be
adjusted accordingly.) *P* (the multiplied factor on the right-hand side of
the equation) is the initial population which, in our case, is eight. The
growth rate is *r* which would be close to zero for humanity per year. A
negative value would indicate a population decline. Henry Morris used a
value for *r* of 0.0033 [0.33%] in a similar calculation which started with
Adam and Eve. However, since the flood supposedly reduced the population to
eight people 1656 years after creation, a figure Dr. Hovind gives based on
patriarchal ages, we should start our exponential curve at the latter date.
If we assume, for the sake of this argument, that the earth is 6000 years
old, then we start our calculation with 8 people 4344 years ago. We must
wind up with the present population of 5.5 billion people.

It turns out that if *r = 0.0047* then after 4344 years we would wind up
with about 5.6 billion people (1995), which is close enough. After
substituting the values for *P* and *r* into the above equation we are at
liberty to try out different values for *n* to obtain the population at
different times. At the time the Israelites entered Canaan, for instance, we
get a world population of 2024! By the time you divide that up between
Egypt, Canaan, the rest of the world, and Israel, that leaves maybe 6 or 7
people for the Israeli army! If we go back to the time that the Hykos were
expelled from Egypt, in 1560 BC, we get a world population of 325 people!

We can't calculate the population at the time the Great Pyramid of Cheops
was built, around 2500 BC, because it was supposedly washed away by Noah's
flood!! Being an antediluvian structure, many people might have been
available to work on it. Odd, that the Great Pyramid of Cheops shows no
water marks. Stranger still, that the Egyptians should be unaware of Noah's
flood! I would think that Noah's flood, coming a mere century or thereabouts
after the Great Pyramid of Cheops was built, would have found a prominent
place in the Egyptian annals.

As you can see, an exponential growth curve leads to absurdity when we
assume that 8 people generated today's population. Creationists, of course,
could jack the *r* value way up at the start, jack it way down in the
middle, and jack it up again for modern times, but the *ad hoc* nature of
such an argument becomes a little *too* obvious. Regarding the foolishness
of this whole enterprise, Dr. Alan Hayward had this to say:

Nobody who has ever studied the population explosion would make such an
unwise extrapolation. It is well known that growth rates have increased
enormously in recent centuries. Population expert Paul Ehrlich gives world
average yearly growth rates of 0.9 per cent between 1850 and 1930, 0.3 per
cent between 1650 and 1850, and a mere 0.07 per cent in the thousand years
prior to 1650. And in the fourteenth century the population increase must
have been very small indeed, and it may even have been turned into a big *
decrease*, because of the Black Death. Ehrlich's figures are not just
guesses; they are based on historical records. These facts show how
misguided it is to extrapolate present population trends into the remote
past.

(Hayward, 1985<http://www.talkorigins.org/faqs/hovind/howgood-refs.html#Hayward1985>,
p.136)

*The Times Atlas of World History*
(1978<http://www.talkorigins.org/faqs/hovind/howgood-refs.html#Times1978>)
estimated that the world population increased 16 times between 8000 BC and
4000 BC. That yields a growth rate (*r* = *0.069*%) which is almost
identical to the figure quoted above by Hayward for ancient times.

Try plugging in some real data! It does make a difference. If we assume a
growth rate of 0.07% before 1650 (a rate already a bit high because of
agriculture), a growth rate of 0.3% between 1650 and 1850, a growth rate of
0.9% between 1850 and 1930, and a growth rate of 2.0% between 1930 and 1994
you will find that Noah and his crew are the ancestors of a whopping 1740
people today!

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Pretty good. The people at talkorigins do a great job at rebuttals. Their
"index to creationist claims" (http://talkorigins.org/indexcc/) is one that
should be on the favorites of anyone interested in origins.

-David Buller

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Received on Thu Apr 26 20:53:51 2007