Juliawing23 (talk) 19:55, 29 February 2016 (UTC)
Biological Basis of Menopause (Additional Information for Missing Citations)
From Wiki: Removal of the uterus without removal of the ovaries does not directly cause menopause, although pelvic surgery of this type can often precipitate a somewhat earlier menopause, perhaps because of a compromised blood supply to the ovaries.[citation needed]
Symptoms of menopause may be more severe following hysterectomy and could lead to reduced sexual pleasure in some cases. Observational studies indicate growing evidence that surgical menopause may impact negatively on future cardiovascular, psychosexual, cognitive and mental health.However removal of ovaries could possibly reduce incidences of ovarian cancer so the leaving of ovaries in hysterectomy is an individual choice.
[1][2]
From Wiki: Long term effects[edit]Menopause confers:A possible but contentious increased risk of atherosclerosis[20] The risk of acute myocardial infarction and other cardiovascular diseases rises sharply after menopause, but the risk can be reduced by managing risk factors, such as tobacco smoking, hypertension, increased blood lipids and body weight.[21][22] Increased risk of osteopenia and osteoporosis[citation needed]
There are multiple risk factors of osteoporosis including genetic factors, low body mass index. It is triggered by a dramatic increase in cytokines involved in bone remodeling with net increase in bone reabsorption. As adequate calcium intake may be vital for maintaining peak bone mass theses changes may be reversed by estrogen therapy.
[3]
From Wiki:Generally speaking, women raised in the Western world or developed countries in Asia live long enough so that a third of their life is spent in post-menopause. For some women, the menopausal transition represents a major life change, similar to menarche in the magnitude of its social and psychological significance. Although the significance of the changes that surround menarche is fairly well recognized, in countries such as the United States, the social and psychological ramifications of the menopause transition are frequently ignored or underestimated.[citation needed]
[4][5]
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3912906/
Basics of Menopause Progression: Follicular atresia
In-Law Competition
Here is a primary article featuring the database of Finns that Prof. Promislow talked about. http://www.ncbi.nlm.nih.gov/pubmed/22913671
This study argues that an important component of menopause evolution in humans in reproductive conflict between unrelated women, such as mother and daughter in law. The study takes into account the reproductive overlap between generations of women. For example, the reproductive overlap between a mother and daughter was unlikely to have selected against increasing age of fertility in the older generation. That occurs because the daughter is equally related to the older generation's offspring (degree of relatedness R=0.5), however the mother from the older generation will be always be half as related to her daughter's offspring (R=0.25). From an evolutionary standpoint, it does not make sense to out compete someone to whom you have such a close degree of relatedness. On the other hand, mother-in-law and daughter-in-law are not bound by the same principles of relatedness, there fore competition occurs between the two generations of in-laws to pass down their own genes. More specifically, mother-in-laws will be more related to their offspring (R=0.5) than their daughter-in-law's (R=0.25), and daughter-in-laws will be completely unrelated to their mother-in-law's offspring (R=0). Thus the younger daughter-in-laws will be under greater selection to "win" the reproductive conflict between the two generations. This is the user sandbox of Laurenvd22. A user sandbox is a subpage of the user's user page. It serves as a testing spot and page development space for the user and is not an encyclopedia article. Create or edit your own sandbox here.Other sandboxes: Main sandbox | Tutorial sandbox 1, 2, 3, 4, 5 | Template sandbox Writing an article and ready to request its creation? Save your work by pressing the "Save page" button below, and a button will appear here allowing you to submit your draft for review.
Evolutionary Mechanism/Driving Forces of the Evolution of Menopause (source list for the content i'll be writing-KD)
A new study argues that in-law competition drove the evolution of menopause. But is the story too good to be true? http://blogs.scientificamerican.com/primate-diaries/a-grimm-tale-of-reproductive-conflict/ Reproductive conflict and the separation of reproductive generations in humans http://www.pnas.org/content/105/14/5332.abstract? Ecology drives intragenomic conflict over menopause http://onlinelibrary.wiley.com/doi/10.1111/ele.12208/pdf
Draft #1 of addition to Evolution Section
Evolutionary Mechanisms/Driving forces for the Evolution of Menopause
Women go through menopause about half way through their lifespan. Because humans, killer whales, and pilot whales are the only species confirmed to go through menopause there are a number of hypotheses about why this occurs. [6]Demarrek19871 (talk) 23:31, 28 February 2016 (UTC)
Reproductive Conflict Hypothesis Reproductive senescence coincides with the age at which reproductive competition from younger females would begin. While post-reproductive survival can be selected for to help a woman's own children reproduce, it is argued here that kin-selected fitness gains do not outweigh the potential gains of continued reproduction. Kin-selected benefits explain post-reproductive survival but not early reproductive senescence [7]. The reproductive conflict hypothesis suggests that menopause is the outcome of reproductive competition in generations within social units and is complimentary to the Grandmother Hypothesis.Demarrek19871 (talk) 23:31, 28 February 2016 (UTC)
In-Law Competition Another related theory is the In-law Hypothesis. When women and their mother in-law had children within two years of each other had reduced infant survivor-ship by 50% [8]. However, there was no decline in survivor-ship when women and their own mothers had children at the same time. The decline in infant survivor-ship is hypothesized to have driven the evolution of menopause. It would have been adaptive for women to stop ovulation before their daughter's in-law began to have children and therefore the small reproductive overlap is the result of previous stabilizing selection pressures [9]. One potential issue with the in-law hypothesis is that the study was conducted using data from a relatively non-migratory population, as compared to our by majority hunter-gatherer ancestors.Demarrek19871 (talk) 23:34, 28 February 2016 (UTC)
Change in Mating Behavior Hypothesis
This non-adaptive hypothesis suggests that at some point in time, there was shift in preference for younger females or that younger females were out competing older females for mates. If there was a population that was long-lived and able to produce throughout their lifetimes, then gender specific mutations that diminished fertility late in life would be selected against. However, this proposed change in mating behavior would result in only young females reproducing thereby reducing the natural selection on older females [10]. With relaxed natural selection on older females, the mutations reducing fertility would become neutral, allowing them to accumulate and female fertility would thus decline with age. This hypothesis suggests that this accumulation of now neutral mutations would gradually result in the evolution of menopause. When using computer models to explore the hypothesis, it was also found to be true if only young males mate, resulting in male menopause [11].
Demarrek19871 (talk) 23:31, 28 February 2016 (UTC)
Female lifespan increase
One hypothesis to explain menopause is that humans didn’t live as long as we do now with modern medicine and that, in our natural environment (i.e. the African savanna 100,000 years ago), women never would have lived long enough to reach menopause. It is a known fact that modern indigenous people (many of whom live in environments similar to that of our distant African ancestors) have an average lifespan between 35-40. But the high infant mortality in these populations is skewing that statistic to make it seem that adults are dying younger than they are. Most modern hunter-gatherers, if they make it through childhood, will reach a ripe old age. So that can’t be the reason for menopause. ↑ Hickey, M.; Ambekar, M.; Hammond, I. (2010-04-01). "Should the ovaries be removed or retained at the time of hysterectomy for benign disease?". Human Reproduction Update 16 (2): 131–141. doi:10.1093/humupd/dmp037. ISSN 1460-2369. PMID 19793841. ↑ Nichols, Hazel B.; Visvanathan, Kala; Newcomb, Polly A.; Hampton, John M.; Egan, Kathleen M.; Titus-Ernstoff, Linda; Trentham-Dietz, Amy (2011-05-15). "Bilateral oophorectomy in relation to risk of postmenopausal breast cancer: confounding by nonmalignant indications for surgery?". American Journal of Epidemiology 173 (10): 1111–1120. doi:10.1093/aje/kwq510. ISSN 1476-6256. PMC 3105288. PMID 21430192. ↑ Saied, Mary Naim Ayad (2001). "Osteoporosis and Menopause". Masters Thesis. ↑ Utian, W. H.; Boggs, P. P. (1999-01-01). "The North American Menopause Society 1998 Menopause Survey. Part I: Postmenopausal women's perceptions about menopause and midlife". Menopause (New York, N.Y.) 6 (2): 122–128. ISSN 1072-3714. PMID 10374218. ↑ Ettinger, B.; Woods, N. F.; Barrett-Connor, E.; Pressman, A. (2000-06-01). "The North American Menopause Society 1998 menopause survey: Part II. Counseling about hormone replacement therapy: association with socioeconomic status and access to medical care". Menopause (New York, N.Y.) 7 (3): 143–148. ISSN 1072-3714. PMID 10810958. ↑ Sanderson, Katharine. "In-law infighting boosted evolution of menopause". Nature. Nature Publishing Group. Retrieved 28 February 2016. ↑ Cant, Micheal; Johnstone, Rufus. "Reproductive conflict and the separation of reproductive generations in humans". Proceedings of the National Academy of Sciences of the United States of America. Highwire Press. Retrieved 28 February 2016. ↑ Johnson, Eric. "A Grimm Tale of Reproductive Conflict". Scientific American. Nature America Inc. Retrieved 28 February 2016. ↑ Johnson, Eric. "A Grimm Tale of Reproductive Conflict". Scientific American. Nature America Inc. Retrieved 28 February 2016. ↑ Stone, John. "Putting the Men in Menopause". The Scientist. LabX Media Group. Retrieved 28 February 2016. ↑ Stone, John. "Putting the Men in Menopause". The Scientist. LabX Media Group. Retrieved 28 February 2016.
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