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There is an extremely important difference between "every woman has fewer children than her mother" and "on average a woman has fewer children than her mother".
by bo1024 4y ago
There is an extremely important difference between "every woman has fewer children than her mother" and "on average a woman has fewer children than her mother".
You can see that in the first scenario the human race dies out in about 12 generations as the maximum possible number of children any woman can have decreases by 1 each generation.
The second scenario is easily compatible with sustained long-term population growth. For example each woman initially has four kids, two of whom are childless and two of whom have four kids, etc. This doubles the population each generation but on average a woman has half as many children as her mother (two fewer).
- dmurray 4y agoIt doubled in the first generation (one woman and presumably one man produced four kids) In the following generation, the population didn't increase. Four people and their four partners collectively produced eight kids.
- bo1024 4y agoAh, great catch. I keep forgetting about sexual reproduction. To correct the point while keeping the math easy, make it 8 kids each, half of whom have 8 kids and half none, etc. Then each couple contributes on average to two couples in the next generation, etc.
- smegsicle 4y ago> I keep forgetting about sexual reproduction a problem all too common in these fields