https://www.sapiens.org/evolution/human-...evolution/
EXCERPTS: Something curious happened in human population history over the last 1 million years. First, our numbers fell to as low as 18,500, and our ancestors were more endangered than chimpanzees and gorillas. Then we bounced back to extraordinary levels, far surpassing the other great apes.
Today [...] many species are critically endangered. Meanwhile, the human population has surged to 7.7 billion. And the irony is: Our astonishing ability to multiply now threatens the long-term sustainability of many species, including ours. What happened? [...] Saving women time and energy is central to increasing the population. And humans have developed numerous technological and social ways of accomplishing this that differ from our great ape relatives.
[...] Somewhere along the evolutionary road, humans started to favor new ways of having and raising their young. Mothers began weaning their infants earlier. ... Breastfeeding is calorically expensive. It takes a mother about 600 extra calories a day to produce milk. So, the sooner she stops nursing, the sooner she can biologically support another pregnancy.
[...] Our ancient ancestors also fed, sheltered, and cared for youngsters who were weaned but still growing. This gave them a better chance at surviving than nonhuman great ape young, which fend for themselves after they’re weaned.
[...] Having lots of kids is great for the success of the species. But there’s a hitch. Mothers don’t have enough hours in the day to care for their babies full time while providing for their older offspring. That’s especially true because the unique aspects of the human diet give mothers a lot of tasks to juggle.
There are simply not enough hours in the day for any one person to accomplish all this. So, our ancestors came up with a solution. That solution was cooperation—but not the kind of task-sharing many species engage in. Hunter-gatherers developed a distinct feature called intergenerational cooperation: Parents help kids, and children help parents.
This is not a trait we share with the other great apes [...] among humans, intergenerational cooperation means it really does take a village to raise a child. ... Fathers and grandparents certainly play important roles in supporting their families. But it’s not enough. ... My research suggests a much more obvious source of help has been overlooked: kids. Other than mothers, children provide most of the child care in many cultures. And 7- to 10-year-olds do the bulk of the babysitting.
Children are also responsible for processing much of the food and running the household. [...] Children in agricultural communities are also hard workers. ... between the ages of 7 and 14 [kids] devote two to five hours a day to domestic and field work. Teens between the ages of 15 and 18 labor about 6.5 hours a day—as much as their parents. [...] Thanks to this multigenerational help, a woman can spend time doing what only she can do: have more children. So, children increase the population, but their labor is also a built-in engine to fuel their community’s fertility and speed up reproduction.
With intergenerational cooperation and a diversity of dietary strategies, our ancestors multiplied and weathered population bottlenecks. Just after 1800, the human population hit 1 billion. [...] There is no question ... that humans have been incredibly successful. The question is: How long can we maintain that success and still be sustainable? The answer, like our secret to growth in the past, stands on the shoulders of cooperation... (MORE - details)
EXCERPTS: Something curious happened in human population history over the last 1 million years. First, our numbers fell to as low as 18,500, and our ancestors were more endangered than chimpanzees and gorillas. Then we bounced back to extraordinary levels, far surpassing the other great apes.
Today [...] many species are critically endangered. Meanwhile, the human population has surged to 7.7 billion. And the irony is: Our astonishing ability to multiply now threatens the long-term sustainability of many species, including ours. What happened? [...] Saving women time and energy is central to increasing the population. And humans have developed numerous technological and social ways of accomplishing this that differ from our great ape relatives.
[...] Somewhere along the evolutionary road, humans started to favor new ways of having and raising their young. Mothers began weaning their infants earlier. ... Breastfeeding is calorically expensive. It takes a mother about 600 extra calories a day to produce milk. So, the sooner she stops nursing, the sooner she can biologically support another pregnancy.
[...] Our ancient ancestors also fed, sheltered, and cared for youngsters who were weaned but still growing. This gave them a better chance at surviving than nonhuman great ape young, which fend for themselves after they’re weaned.
[...] Having lots of kids is great for the success of the species. But there’s a hitch. Mothers don’t have enough hours in the day to care for their babies full time while providing for their older offspring. That’s especially true because the unique aspects of the human diet give mothers a lot of tasks to juggle.
There are simply not enough hours in the day for any one person to accomplish all this. So, our ancestors came up with a solution. That solution was cooperation—but not the kind of task-sharing many species engage in. Hunter-gatherers developed a distinct feature called intergenerational cooperation: Parents help kids, and children help parents.
This is not a trait we share with the other great apes [...] among humans, intergenerational cooperation means it really does take a village to raise a child. ... Fathers and grandparents certainly play important roles in supporting their families. But it’s not enough. ... My research suggests a much more obvious source of help has been overlooked: kids. Other than mothers, children provide most of the child care in many cultures. And 7- to 10-year-olds do the bulk of the babysitting.
Children are also responsible for processing much of the food and running the household. [...] Children in agricultural communities are also hard workers. ... between the ages of 7 and 14 [kids] devote two to five hours a day to domestic and field work. Teens between the ages of 15 and 18 labor about 6.5 hours a day—as much as their parents. [...] Thanks to this multigenerational help, a woman can spend time doing what only she can do: have more children. So, children increase the population, but their labor is also a built-in engine to fuel their community’s fertility and speed up reproduction.
With intergenerational cooperation and a diversity of dietary strategies, our ancestors multiplied and weathered population bottlenecks. Just after 1800, the human population hit 1 billion. [...] There is no question ... that humans have been incredibly successful. The question is: How long can we maintain that success and still be sustainable? The answer, like our secret to growth in the past, stands on the shoulders of cooperation... (MORE - details)