to ponder that evolutionary women may well were chosen to look after their off spring(55 Posts)
in the way they do....i.e. often more close and full on parent.....
just thinking this of other debates, not just on mn, so, not a thread about a thread.....because men can have baby's whatever age, and are meant to die younger than women, but women have a biological cut off date....?
personally I do believe we all have the same human rights, but that we are generally wired differently depending on many things, such as race, sex....but I do think that women are evolutionary and biologically more geared up to parenting, as in remembering everything, to some extent
Disagree on that I'm afraid. Men generally don't do the stuff we do because they don't have to.
Certainly we are 'designed' to do child raising when they are very young, we bond very strongly with our babies, have breasts etc, but once the kids get past about 2 the skills required are not innate to either gender.
think that this is a very complicated issue but there are differences in the way men and women are wired. Men are more likely to take risks and do dangerous things, prob because of their higher testosterone levels- ergo more likely to die in battles they have started-whilst the women folk look after the children.
i agree with op really but this doesn't mean it's right or that it has to be that way.
But why do men not have a "cut-off" date? What I mean is....is it because historically men were more likely because they be dead by 50 anyway, whereas women are not, and therefore nature has given women a protection of becoming mothers at a late stage of their life, in order to protect off spring to grow up motherless...and i know you cna be run over by a bus any day....but the higher likelyhood of dying a natural death does come with age...
am not explaining this well at all...it's all sorted in my head, but is coming out in a jumbled mess, sigh...
I actually think creches make the most sense evolutionary wise. So you have all the young together with a few females, younger/older males keeping an eye on them.
With the healthy adults of both sexes out and about finding food.
Lions certainly seem to have the arrangement down. There are not too many animals that will mess with a pride of lions (with the exception of other lions).
In theory I agree with you.
In practice DH is a much better parent than I am
From a strictly evolutionary standpoint there are advantages for women not bearing children past a certain age. Pregnancy and childbirth are risky and the older the mother the higher the risks to both the mother and the child. This is particularly the case with humans as our children are reliant on their parents (and mothers in particular due to BFing) for much, much longer than other animals. Back in prehistoric times, children of older mothers were less likely to grow up and have their own children and so the genes that allowed for later pregnancies were less likely to be carried through to later generations.
As pregnancy and birth don't have any significant impact on male health, and the man can't BF so it's not as vital to the child that the father is alive and well (compared to the utter dependence on the mother for food in the first year or two), so there's less evolutionary advantage in male fertility stopping by a certain age.
All that being said, though, I think love and caring for children is something that anybody can do, regardless of gender. And I think that nurture, rather than nature, has a lot more to do with how members of our society behave than evolutionary biology does.
Eg, while it is true that men do take more risks than women and that might be down to differences in testosterone levels, it's also the case that male risk-taking is more socially acceptable and accepted than it is for women. I'm happy for both DS and DD to climb trees, but I've had comments from more than one person questioning why I'm letting DD do so whereas it's expected that DS would want to.
I agree with kat - a lot of men don't do the bonding etc because they don't have to; and, in some cases, they're actively discouraged from doing so. I've found out that raising children results in making a hell of a lot of mistakes and then having to learn from them. Some women are so protective of their children (and/or dismissive of their partners) that the fathers aren't allowed to make any mistakes as if they make even a minor error, the mother goes ballistic and takes over. Just as mothers need space, lee-way and understanding to allow them to develop their own parenting styles, so do fathers.
Snorbs....that was what I tried to get too...thank you!
Btw....this was never about Man are not as good parents, etc....because many many man are fabulous fathers....
I suppose with that debate about the Lady that had IVF at a very late age, had Baby's and than sadly died of cancer, and people taking such moral issue with it and other people saying, but why are we so down on women when no one bats an eyelid about older dads....I sort of started pondering that there must be a reason why women , by nature, shouldn't have Babies at an old age...
The thing is they have recently discovered that while men don't have an abruput "cut off" like women, the quality of sperm starts to degrade dramatically after about 30 (IIRC).
They found that men trying to conceive later were more likely to have partners suffering multiple miscarriages (which of course were put down to the woman rather than the man) and are more likely to father children with various difficulties.
So while there's not a "cut off" it is preferable from an evolutionary point of view to mate with a younger man, for the best chance of a successful pregnancy and healthy offspring.
None of this stuff is straightforward, and personally I am of the view that the sexes behave as they are programmed to by society to a large extent, and the differences between individuals are what is interesting. eg DH is a much soppier parent and was far more broody than me. Further I think this is fairly common, so there are enough people displaying the opposite "gender characteristics" as to mean that any "gender trait" is less statistically relevant IYSWIM.
Why do women get one dollop of eggs and men get to make sperm as and when necessary?
Cats don't have menopause, they are fertile throughout their lives. They also only ovulate if they mate.
Presumably there are evolutionary benefits to menopause in humans(or perhaps it's a mistake/oversight or by-product of something else that was more evolutinary favourable). But it doesn't seem as though nature thought it was a good plan for all mammals.
From a biological point of view, a woman's body invests a huge amount of energy and resources into having a child, from pregnancy to BFing. A man's body doesn't. That, more than anything else, makes the difference.
(Note, I'm going to talk about this from an evolutionary biology standpoint - I'm not talking about what's morally right or wrong)
Evolution (which is all about which genes get to replicate down the ages) would suggest that it makes sense for a woman to a) limit the number of children she has, b) make sure those children are as healthy and likely to survive as possible, and c) avoid having too many children so as not to deplete her resources too much as a mother who's run down won't be able to nuture her children. If her children die because she can't provide breastmilk for them, or because she's died in childbirth, or because she's died because she's simply too old, then in evolutionary terms she's a dead-end.
Conversely, evolution would suggest that it makes sense for a man to a) have as many healthy children as possible, and b) have those children with a number of different mothers to increase the odds of his own genes replicating down the ages. Neither of those are markedly affected by the age of the father.
There's a fascinating (honest!) book called "Y: The Descent of Men" about the Y-chromosome in particular and genetic differences between the sexes in general. It seems that, at the genetic level, there's an arms race between men and women and it's been going on for millenia. Women's genes evolve lots of defences against weak sperm (because strong children are more likely to have children of their own), while men's genes evolve lots of ways around those defences (because if your sperm can't impregnate an egg, you're not going to be an ancestor).
"The thing is they have recently discovered that while men don't have an abruput "cut off" like women, the quality of sperm starts to degrade dramatically after about 30 (IIRC)."
LovelyTinOfSpam, I didn't know that. Interesting. In which case, you've just blown a huge hole in my carefully crafted post above
juule, one of the downsides of human intelligence is a big brain. Which means a big skull to store it in. Which causes trouble in childbirth as that big skull has to fit through the pelvis.
Sooo, human babies are born relatively early and relatively undeveloped because to wait any longer would mean that their big heads wouldn't fit through their mother's pelvis. The result of this is that human babies are pretty much entirely helpless for months. By contrast, other mammals have babies that are up on their feet in days at most, if not minutes.
Also, for that big human brain to develop enough that it can work out what's safe to eat and what isn't takes years, during which time the child has to be constantly looked after. All that creates a lot of dependence on the parents of a human baby for a lot, lot longer than is the case with other animals.
Yes I know that snorbs but I'm not sure that explains menopause.
Have just been trying to find the thing I read but I can't now which is pretty irritating. I'm pretty sure I didn't make it up though!
Nature seems to hit the jackpot on reproduction with the kangaroo.
"Another incredible aspect is that the doe can determine the sex of her offspring. How she does this is unknown, but she tends to put off bearing males until she is older. Males move away after about two years, but females stay with their mothers longer and benefit from ongoing support.
A doe is nearly always pregnant. From sexual maturity to death, she is rarely without three offspringan embryo in the womb, a joey in her pouch, and a larger youngster at her heels.
The joey is born after a gestation period of about 35 days (depending on the species) and in the largest species is the size of a human thumb nail. In the smallest, it is only the size of a rice grain. Naked, blind and deaf, it must make its way unaided from the birth canal to the pouch.
All going well, the climb will take less than 10 minutes. The joey can survive only a few minutes unless it reaches the pouch and attaches to one of the four nipples. Once there, its mouth swells on the nipple so that it cannot be removed without injury. A ring of strong muscles, similar to human lips, seals off the opening to the pouch to protect the joey from bouncing out, and keeps the pouch waterproof if mother goes for a swim.
After three months, the developed joey emerges from the pouch to make short trips in the outside world. However, it will return to the pouch to suckle and sleep until eight months old."
From here -
Well, let's say that average life expectancy for Mrs CaveDweller was 45 years. If she had a child at 40, the chances are she'd be dead before that child reached an age where it was able to fend for itself. Moreover, by having a child at such a (relatively) old age would put additional strain on her body, and increased risk of death in childbirth, which might lead to an earlier than expected death for her which would also put the rest of her children at risk.
If, on the other hand, she stopped being fertile at, say, 35 (I think I read somewhere that the menopause comes early for those who are malnourished or otherwise struggling) then even her youngest child is likely to be self-sufficient by the time she shuffled off this mortal coil. And her youngest child wouldn've been born while she was still (relatively) strong and could cope better with the demands that pregnancy and childbirth would place on her body.
From an evolution advantage standpoint, when pregnancy is risky and "costly", and children are dependent on mothers for a long time, there are benefits in the mother's fertility stopping some time before the mother is likely to die.
But possibly any child mrs cavedweller had when she was around 12/13 onwards would be old enough to care for new baby. Childbirth wasn't just risky for older mothers either so it's possible other females might pick up the slack on orphans. Although that would be just good fortune on the babies part. But then reaching puberty in mrs cavedweller's time was probably good fortune anyway.
this is a great read and right up the alley of this thread
Does childbirth get easier the more you have?
Just thinking about an excellent scientific source - the "every sperm is sacred" monty python sketch from the meaning of life. The mum is on about her 300th baby and it just drops out.
So if you were a cavewoman and you safely delivered your first few, wouldn't the risk get less and less?
I think the kangaroos have it right. Sounds far better having something the size of a fingernail wriggling its way out than trying to squeeze a whole baby.
Juule, that's a fair point about older children helping to care for younger ones. That would depend a lot on the dynamics of the social group though. I'm not sure but I seem to recall reading that with most (all?) primates, care for the younger ones was something that was shared to a certain extent amongst the group.
Nevertheless it was rare that a baby would be suckled by any mother other than its own. A baby whose mother had died would be more likely to starve than be taken care of by another mother. Shared care on any level more complex than generally looking out for other group members requires a degree of altruism which is possibly too subtle for basic genetics to allow. You need intelligence for that and it's possible our breeding patterns were largely set before our levels of intelligence had advanced that far.
LovelyTinOfSpam, the comparative risks of the actual birth between younger, inexperienced mothers and older, experienced ones isn't something I'm confident about. As you suggest I'd also guess that a mother of 10 is, say, less likely to tear than a mother for whom this is her first, but on the other hand I wonder if risks of other complications increases. I have read, though, that older mothers tend to take longer to recover from the birth, their bodies lose more calcium and other reserves during pregnancy, and they take longer to replenish those reserves afterwards.
Snorbs I'm not sure that it would be true that a baby would rarely be suckled by any woman but it's own mother. Lots of possibilities there in that a mother may have had a stillbirth or been friends with the baby's mother or just had a rush of hormones and care about all babies for instance. The baby would possibly be weaned early? As you say it would probably depend on relationships in the communal group.
As regards birth being easier with subsequent pregnancies. Just going off my own experiences, I found that my first birth was the most difficult. The next 8 were straightforward and without any complications and recovery was quicker despite my increasing age. While a woman's body can use up calcium and other reserves, with a good diet(which I would think is the key regardless of age of the mother)they are quickly built back up and I believe that breastfeeding protects against osteoporosis.
Why, thank you, crazycanuck
Had a quick look at that book you linked to. It looks interesting. I'm considering getting it. Not in my local library though so might have to buy it.
juules, as I said my recollection of primate behaviour (chimps, gorillas etc) is that babies are rarely suckled by any mother other than its own. I know that human mothers in primitive societies these days would be different but, at some point in our evolution, we weren't that different from the other great apes.
I suppose it depends a lot on at which point in human evolution that the menopause came about. At some point in our evolution, our intelligence started having more of an effect on our behaviour than our genetic instincts did. From what I've read, that moment quite possibly coincided with the development of a spoken language that could convey abstract concepts.
From a genetic/evolutionary point of view, a mother suckling any child other than its own confers little if any advantage to that mother. The mother would have to obtain and consume enough calories to produce the milk which would then be given to a child bearing genes other than her own. I can't quite see how a gene that promoted such behaviour in the mother would make that mother's children be successful enough to out-reproduce the children of mothers who save their milk for their own kids. But there would have to be that kind of success to prevent the "suckle other babies" gene from dying out.
Sure, once language advanced enough to be able to express a concept of (say) "If you suckle my baby right now, I'll go off and get us both something to eat and then we can swap over tomorrow" then things will be very different and altruism will flourish. But that's altruism driven by intellect rather than by instinct driven by genes.
Eg, the change from a hunter/gatherer lifestyle to one based on farming requires altruism on the part of the farmer (or the abstract concepts of quid pro quo and/or barter). But, by then, intelligence is more important than instinct, and advancement is driven more by intellect, communication and societies than Darwinian evolution. Genetic evolution of major behavioural traits slows down or stops entirely in such circumstances.
So if we as humans had already evolved the menopause long before we got to the point where (intellect-driven) altruism was possible, we could well be stuck with it.
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