3 ms·

One of the reasons we live so long is that the evolutionary pressure is not negative after reproduction; To begin with it takes 15+ years to raise human offspr

by cortic 4y ago

One of the reasons we live so long is that the evolutionary pressure is not negative after reproduction; To begin with it takes 15+ years to raise human offspring to a stage where they might be able to fend for themselves. 20+ years to give them advantage in the environment. Grandparents relieving this burden for each generation greatly increases their reproductive success, far beyond procreation. This is of course similar to other animals, but the benefits are amplified by at least two major factors in humans. First the usefulness of inherited complex knowledge. And second, because of fetal underdevelopment due to birthing hip limitations in evolved bipedal locomotion.

throw827474737 4y ago
Hm not true, a lot of other factors like medicine more relevant, would even say that modern human society has taken out almost all evolutionary pressure except for really bad conditions?!
- klipt 4y ago
  Not at all, in fact modern society has added many new evolutionary pressures. E.g. by inventing birth control, society gave an evolutionary advantage to people who refuse to use birth control for religious reasons, or people whose biology is incompatible with birth control, e.g. a woman for whom the pill just doesn't work, is likely to have more children.
  - leaflets2 4y ago
    And gave a disadvantage to brighter women who study at university and do research, and postpone making kids
  - throw827474737 4y ago
    Yes but come on, that is so different that it shouldn't be even termed "evolutionary pressure" (in the usual original sense of survival of the fittest)?!
    - klipt 4y ago
      Why? Fitness is and always has been relative to the environment in which one lives. It just happens that our environment is now largely man-made.
Aperocky 4y ago
Evolution is not a precise tool, just because there are pressure doesn't mean it will manifest or even have a chance to manifest. No guarantee that a genetic behavior that kills parent individual after raising their young will not affect other things before that. Especially 'raising the young' is an indeterminate period that are hard to biologically determine. Contrast that with species that don't have to raise their young, most of them (insects, salmon, etc) die right after reproduction. Inherited complex knowledge and human society did not form until a few thousand years ago, that is about 150 generations where we can say we are 'relatively' civilized and maybe 10 where we are industrialized. That is an awful short time for evolution to do anything. Coupled that with the complete change of selective pressure in modern society (most individuals are no longer under selective pressure, but personal and cultural choice affect child-bearing way more), it's hard to say where human evolution will lead.
- b112 4y ago
  Inherited complex knowledge and human society did not form until a few thousand years ago I think you are vastly underestimating millions of years to the contrary. Tribal living had complex knowledge. Just how to make a bow, a spear, preserve food, build shelter, cloth themselves, hunt, harvest crops, treat many illnesses with local plants, coupled with the fact that it all had to be learned in great detail, first hand, for there was only oral history. Even things such as "where are the animals" and "where are the apples" is complex, when drought, inclement weather, might cause local shortage, and traveling as the grandparent remembers "when I was young" for some alternate food means everything. There are plants which taste like crap, but will keep you alive, but that sort of knowledge is lost unless you have Google (grandparents) around. Have you looked at how corn meal is prepared in native cultures? I can't even imagine how many centuries, or thousands of years of trial and error that took, to make it edible. https://en.m.wikipedia.org/wiki/Nixtamalization https://en.m.wikipedia.org/wiki/Nixtamalization What about our wormy Guinea friend? https://www.britannica.com/science/guinea-worm-disease https://www.britannica.com/science/guinea-worm-disease If you yank this worm out, it typically rups in half. The remainder rots inside your flesh, usually killing you without modern medical care Who retains that knowledge, for when an outbreak hits the tribe? Who lives long enough, to notice over time (decades of adult life) what might cause the parasite. Without paper, without Google, without written language, everything learned must be transferred to the next generation of grandparents. By having free time, by talking. And grandparents can do many tasks which active hunters and gatherers cannot, for they have no time! Repairing and maintaining weapons, fixing clothing, transport vessles, preparing food (which can take hours and hours), and so on.

by cortic 4y ago

throw827474737 4y ago

Hm not true, a lot of other factors like medicine more relevant, would even say that modern human society has taken out almost all evolutionary pressure except for really bad conditions?!

klipt 4y ago
Not at all, in fact modern society has added many new evolutionary pressures. E.g. by inventing birth control, society gave an evolutionary advantage to people who refuse to use birth control for religious reasons, or people whose biology is incompatible with birth control, e.g. a woman for whom the pill just doesn't work, is likely to have more children.
- leaflets2 4y ago
  And gave a disadvantage to brighter women who study at university and do research, and postpone making kids
- throw827474737 4y ago
  Yes but come on, that is so different that it shouldn't be even termed "evolutionary pressure" (in the usual original sense of survival of the fittest)?!
  - klipt 4y ago
    Why? Fitness is and always has been relative to the environment in which one lives. It just happens that our environment is now largely man-made.

Aperocky 4y ago

Evolution is not a precise tool, just because there are pressure doesn't mean it will manifest or even have a chance to manifest. No guarantee that a genetic behavior that kills parent individual after raising their young will not affect other things before that. Especially 'raising the young' is an indeterminate period that are hard to biologically determine. Contrast that with species that don't have to raise their young, most of them (insects, salmon, etc) die right after reproduction. Inherited complex knowledge and human society did not form until a few thousand years ago, that is about 150 generations where we can say we are 'relatively' civilized and maybe 10 where we are industrialized. That is an awful short time for evolution to do anything. Coupled that with the complete change of selective pressure in modern society (most individuals are no longer under selective pressure, but personal and cultural choice affect child-bearing way more), it's hard to say where human evolution will lead.

b112 4y ago
Inherited complex knowledge and human society did not form until a few thousand years ago I think you are vastly underestimating millions of years to the contrary. Tribal living had complex knowledge. Just how to make a bow, a spear, preserve food, build shelter, cloth themselves, hunt, harvest crops, treat many illnesses with local plants, coupled with the fact that it all had to be learned in great detail, first hand, for there was only oral history. Even things such as "where are the animals" and "where are the apples" is complex, when drought, inclement weather, might cause local shortage, and traveling as the grandparent remembers "when I was young" for some alternate food means everything. There are plants which taste like crap, but will keep you alive, but that sort of knowledge is lost unless you have Google (grandparents) around. Have you looked at how corn meal is prepared in native cultures? I can't even imagine how many centuries, or thousands of years of trial and error that took, to make it edible. https://en.m.wikipedia.org/wiki/Nixtamalization https://en.m.wikipedia.org/wiki/Nixtamalization What about our wormy Guinea friend? https://www.britannica.com/science/guinea-worm-disease https://www.britannica.com/science/guinea-worm-disease If you yank this worm out, it typically rups in half. The remainder rots inside your flesh, usually killing you without modern medical care Who retains that knowledge, for when an outbreak hits the tribe? Who lives long enough, to notice over time (decades of adult life) what might cause the parasite. Without paper, without Google, without written language, everything learned must be transferred to the next generation of grandparents. By having free time, by talking. And grandparents can do many tasks which active hunters and gatherers cannot, for they have no time! Repairing and maintaining weapons, fixing clothing, transport vessles, preparing food (which can take hours and hours), and so on.