Mathematics for the Creationists
Time to get some math involved for the creationists .. or anyone who believes that earth was created 6000 years ago.
Let's just make it 7000 as I'm not sure of the exact number.
In the beginning, there were 2 humans, 1 male and 1 female. Now in 2007 there are 6,6 billion people. How many kids has each woman had to reproduce to get to this number in 7000 years? Let's assume that the fertility and the need and desire to have children is invariable for this 7000 years, so each fertile woman will have the same amount of offspring for simplicity. The number of offspring does not have to be rounded to the next full number, but can and should be presented in a decimal number that is in an understandable format.
As the mortality has been significantly higher until only 50-100 years ago, let's assume that fertility = 90 % (optimistic) and that 40 % of people are dead before the age they can reproduce, and 50 % are dead by the age 20. Each birth brings a risk of death of 10 % for the woman. Let's assume that a woman becomes able to have kids at the age of 15, and continues to be fertile until the age 40. (Historically, this is a very optimistic number as so many people had malnutrition and other reasons that caused them to be way less fertile). Each pregnancy lasts 9 months. Each child is breastfed for 6 months. Breastfeeding is the ONLY available form of birth control so during the breastfeeding time a woman does not get pregnant. Condoms, birth control pills, condoms, or even the 'safe days' or pull out methods are totally unknown.
50 % of people born are male and 50 % male. Let's assume that no children are killed or abandoned other than in the figures above. And that the male will be able to reproduce from the age 15 to 50, and that all the people are monogamous. Let's also assume that 4 % of the people are religiously devoted, so that they are not participating in the reproduction. Sexually differentiating population is 2 % and also will not breed. Let's assume that all the breeding population does it all the time, wants to populate the earth and not practice abstinence, and that it takes in average 3 months to get pregnant (optimistic). Nobody else than religious devotees and the sexual differently oriented will stay single.
Let's also assume that there is this Great Flood as many years ago as it happened in the Bible, and that on that year the available population was the amount of people listed to have been in the ark as described in the Bible. For other disasters, wars, diseases etc we assume that the added mortality is 2 % on average years, and that for every area of 10 million people there was some additional disaster ever 200 years that resulted in a sudden 40 % mortality of the people due to disease/war/natural disaster/famine etc, within 5 years of time (people of all ages die at the same rate).
Let's assume that the basic expected life time for a woman and a man not dying for the above mentioned causes before the optimal age, would be 60 until 200 years ago; 70 since then until 100 years ago, and 80 after that. Population loss due to emigration and immigration is ignored. Average number of stillborn or offspring that dies before it reaches 1 year of age is 10 % (again, optimistic). 1 % of births are twins (triplets and more are unviable until last centery so those can be excluded from calculations).
Do the math.
One possible answer so far here.
Let's just make it 7000 as I'm not sure of the exact number.
In the beginning, there were 2 humans, 1 male and 1 female. Now in 2007 there are 6,6 billion people. How many kids has each woman had to reproduce to get to this number in 7000 years? Let's assume that the fertility and the need and desire to have children is invariable for this 7000 years, so each fertile woman will have the same amount of offspring for simplicity. The number of offspring does not have to be rounded to the next full number, but can and should be presented in a decimal number that is in an understandable format.
As the mortality has been significantly higher until only 50-100 years ago, let's assume that fertility = 90 % (optimistic) and that 40 % of people are dead before the age they can reproduce, and 50 % are dead by the age 20. Each birth brings a risk of death of 10 % for the woman. Let's assume that a woman becomes able to have kids at the age of 15, and continues to be fertile until the age 40. (Historically, this is a very optimistic number as so many people had malnutrition and other reasons that caused them to be way less fertile). Each pregnancy lasts 9 months. Each child is breastfed for 6 months. Breastfeeding is the ONLY available form of birth control so during the breastfeeding time a woman does not get pregnant. Condoms, birth control pills, condoms, or even the 'safe days' or pull out methods are totally unknown.
50 % of people born are male and 50 % male. Let's assume that no children are killed or abandoned other than in the figures above. And that the male will be able to reproduce from the age 15 to 50, and that all the people are monogamous. Let's also assume that 4 % of the people are religiously devoted, so that they are not participating in the reproduction. Sexually differentiating population is 2 % and also will not breed. Let's assume that all the breeding population does it all the time, wants to populate the earth and not practice abstinence, and that it takes in average 3 months to get pregnant (optimistic). Nobody else than religious devotees and the sexual differently oriented will stay single.
Let's also assume that there is this Great Flood as many years ago as it happened in the Bible, and that on that year the available population was the amount of people listed to have been in the ark as described in the Bible. For other disasters, wars, diseases etc we assume that the added mortality is 2 % on average years, and that for every area of 10 million people there was some additional disaster ever 200 years that resulted in a sudden 40 % mortality of the people due to disease/war/natural disaster/famine etc, within 5 years of time (people of all ages die at the same rate).
Let's assume that the basic expected life time for a woman and a man not dying for the above mentioned causes before the optimal age, would be 60 until 200 years ago; 70 since then until 100 years ago, and 80 after that. Population loss due to emigration and immigration is ignored. Average number of stillborn or offspring that dies before it reaches 1 year of age is 10 % (again, optimistic). 1 % of births are twins (triplets and more are unviable until last centery so those can be excluded from calculations).
Do the math.
One possible answer so far here.