Menopause (716 hits)
Category: Science & EnvironmentalRating: 1 on 2 reviews (Rate this item) (V)
Submitted by Martes pennanti <fisher.at.go.com> (View user info) at 2002-10-29 15:07:22 EST
I've noticed that there has been an increase of vocal women on this site now. I took an evolutionary analysis class in college about 2-3 years ago; in that class we argued the evolutionary explanation of menopause one day. What was funny about the whole episode was that it was an upper level applied\base biology course with 5 guys in it and no female students. That weekend I had actually researched the topic. Not on the Internet, but in academic journals and textbooks. So, women, this is what I came up with. Hope you enjoy it.
Two hypotheses exist that I know of. One suggests that menopause is a non-adaptive artifact of our modern lifestyle. Thus, it is called the artifact hypothesis. It suggests that life spans were so short early in our history there was no need for women to have children past 50 because they never lived that long. With recent advances in medicine and increases in life spans, our biological evolution was not fast enough to catch up with our cultural evolution. The other hypothesis suggests that menopause is a life history adaptation associated with the contribution grandmothers makes to feed their grandchildren. This hypothesis is called the grandmother hypothesis. This is the hypothesis that I prefer to support and will explain here.
The reason I prefer to side with the grandmother hypothesis is because human children are dependent on their mothers for food for several years after weaning. This is often observed in contemporary hunter-gatherer cultures, especially when most of the food harvested provide high yields for adults but are difficult for children to process. As a result, a women's ability to produce additional children will be limited by her need to provision her older, still dependent children. In addition to this are several trends that occur as women get older: The probability that she will live long enough to be able to nurture another baby from birth to independence declines, the risks associated with childbirth and pregnancy increase, and her own daughters will themselves start to have children. The grandmother hypothesis suggests that older women may reach a point at which they can get more additional copies of their genes into future generations by ceasing to reproduce themselves, and instead helping to provision their weaned grandchildren so that their daughters can have more babies. In other words, grandmothers face a trade-off between investment in children and investment in grandchildren.
I hope this is understandable. I attempted a short explanation so that I wouldn't put people to sleep.
User Reviews
Submitted by fisher at 2002-10-30 01:21:06 EST (#)
Ranking: 0
Well, I think I can come up with one to debate with you. I'm a bit shocked that you dug up those old posts that I wrote. I'll think up an interesting topic to debate you with and submit it.
Submitted by PeopleAreStrange (user info) at 2002-10-29 17:21:31 EST (#)
Ranking: 1
I guess you could count me as one of those vocal women. Unfortunately the title of your topic scared me so much it took me a while to even click in and read it. I'll explain why - I'm young, I don't want to think about the menopause. Thinking about have children one day is scary enough, let alone getting to the time I'm no longer biologically able to.
Also I'm no scientist so my opinions on this will not be educated in any way. I think I understand both of the hypotheses you have presented 1. Women didn't use to be able to have children past the age of 50 because x hundred years ago humans died soon after that age.
2. Women stop being able to have children past 50 because they will be grandmothers and will be needed to support their genes via their daughters children.
My opinion is that women get the menopause because of what you mentioned
"the risks associated with childbirth and pregnancy increase,"
Women don't have periods for the first 11 (slightly more or less) years of their life. This is because their body is not biologically able to support childbirth (pre-pubescent, womb too small etc). I think women stop having periods when they get to around 50 because their body is getting ready to die.
So #1 theory suits me. If this theory is correct women will start having the menopause later in life because female humans are living to a longer age on average, so eventually our bodies will catch up with this.
I can't believe I've just discussed this! Have you not got any really interesting scientific topics to debate? I've read your post about wolves, that was cool, anything else like that?