Human population growth indicates a young earth (Talk.Origins)
From CreationWiki, the encyclopedia of creation science
Claim CB620:
A reasonable assumption of population growth rate (0.5 percent) fits with a population that began with two people about 4000 years ago, not with a human history of millions of years.
Source:
 Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master Books, pp. 167169.
CreationWiki response:
(Talk.Origins quotes in blue)
1. This claim assumes that the population growth rate was always constant, which is a false assumption. Wars and plagues would have caused populations to drop from time to time.
As worded this claim is a straw man, since it is a total misrepresentation of what Dr Morris actually said. The 0.5 percent was not an assumed value but a calculated value. It is the average population growth rate needed to get what was then the world’s population in 4000 years. He shows it to be a reasonable average since it is ¼ the modern average growth rate. Morris makes quite clear that this is only an average and that in reality the rate would some times be higher and some times it would be lower. The fact that this growth rate is ¼ the observed current value shows that factors like wars and plagues are dealt with. Morris is simply showing that the current world population is consistent with the Biblical account.
In particular, population sizes before agriculture would have been severely limited and would have had an average population growth of zero for any number of years.
This proves another part of what Dr Morris actually said, that being that the world population fits naturally with in a Young Earth creation Time frame but that add additional factors are to get it to fit with an Evolution time frame.
2. There is no particular reason to choose a population growth rate of 0.5 percent for the calculation. The population growth from 1000 to 1800 has been closer to 0.1227 percent per year. At that rate, the population would have grown to its present size from the eight Flood survivors in 16,660 years.
Dr Morris did not choose an average growth rate of 0.5 percent, but calculated it. Talk Origins above response is a joke on two accounts.
 Morris’ growth rate of 0.5 percent is an average, not a constant .
 Talk Origins is using a period of time that includes the devastation of Black Plague, which made the growth rate unnaturally low.
By the way if their growth rate lasted just 200,000 years the population would be 6.48 X10^{106}, which is impossibly high. That why they need a near zero growth rate.
3. The population growth rate proposed by the claim would imply unreasonable populations early in history. We will be more generous in our calculations and start with eight people in 2350 B.C.E. (a traditional date for the Flood). Then, assuming a growth rate of 0.5 percent per year, the population after N years is given by P(N) = 8 × (1.005)^{N} The Pyramids of Giza were constructed before 2490 B.C.E., even before the proposed Flood date. Even if we assume they were built 100 years after the flood, then the world population for their construction was 13 people. In 1446 B.C.E., when Moses was said to be leading 600,000 men (plus women and children) on the Exodus, this model of population growth gives 726 people in the world. In 481 B.C.E., Xerxes gathered an army of 2,641,000 (according to Herodotus) when the world population, according to the model, was 89,425. Even allowing for exaggerated numbers, the population model makes no sense 
This one is an even bigger joke since Morris never said the growth rate was constant, but that it is an average. Immediately following the flood the population growth rates would be higher do to factors such as the longer lives that persisted for a time after the Flood and minimum competition for food and water.
By the way the date Talk Origins gives for the Pyramids of Giza assumes the Standard Egyptian Chronology, how ever there are reasons to conclude that the Standard Chronology is wrong.
