Female anatomy

[kempiejon]

I think the issue is the modern life. A human being is proably designed to live 30 to 35 years. But modern life styles, access to food, shelter, medicine etc. extends the life span considerably.

Cats for example, in the wild the lifespan is ~2 years. My moggy is now approaching his 20th birthday as he has a constant supply of food, he gets wormed and defleaed (and these days a monthy shot of anti-biotics). Were as the feral cat does not.

So women are probably designed to be fertile up to their deaths. Just we've managed to extend lifespans.

https://en.wikipedia.org/wiki/Life_expectancy

I'm gonna have to take issue with "designed" but I know what you mean.

[Alaric]

Modern medicine may have added a decade to your biblical three-score-years-and-ten, but not the dramatic difference implied by a claim we all died at 35.

Three-score-years-and-ten as quoted in the Bible is cultural evidence of expected lifespans in ancient times. Expected lifespan at birth is weighted by those who fail to survive to becoming adults.

[Lanark]

Every time you see something in biology which doesnt quite make sense - thats just a sign of chaotic evolution in progress.

A lifeform doesnt have to be perfect it just has to be good enough to work and reproduce.

[DiamondEcho]

Three-score-years-and-ten as quoted in the Bible is cultural evidence of expected lifespans in ancient times. Expected lifespan at birth is weighted by those who fail to survive to becoming adults.

I'm not sure if the bible ever morphed beyond the realms of c4th century/+ fantasy. Meanwhile...

'The average life expectancy for a male child born in the UK between 1276 and 1300 was 31.3 years. In 1998, it is 76. However, by the time the 13th-Century boy had reached 20 he could hope to live to 45, and if he made it to 30 he had a good chance of making it into his fifties.27 Dec 1998
BBC News | Health | A millennium of health improvement
news.bbc.co.uk/2/hi/health/241864.stm

UK/ONS:
' How has life expectancy changed over time? 9 September 2015
In 1841 the average newborn girl was not expected to see her 43rd birthday. Thankfully times have changed and so have life expectancies in the 170 years since the first lifetable was constructed1.
https://www.ons.gov.uk/peoplepopulation ... 2015-09-09

[Alaric]

[i]In 1841 the average newborn girl was not expected to see her 43rd birthday

The key word is newborn. Once infant and child mortality is eliminated the expectation at birth increases dramatically. That doesn't say there were no 60 year olds or 70 year olds in the distant past, because there's the historic records that there were.

[Leothebear]

As an aside, I've often wondered why humans attain puberty so young. Children as young as 10 or 11. When they are generally ill-equipped to deal with the consequences of a sexual relationship.

[Meatyfool]

As an aside, I've often wondered why humans attain puberty so young. Children as young as 10 or 11. When they are generally ill-equipped to deal with the consequences of a sexual relationship.

Animals need to breed as soon as possible in order to ensure the survival of the species. As to a child being ill-equipped to deal with a child of its own, that is what older members of the family/tribe are for - someone earlier asked why older women can't have children, here is one part of the answer.

Before anyone can have a chance to reply with what I suspect may come my way, today we have ethical/moral/legal imperatives for not "breed[ing[ as soon as possible", but we do have our intellectual/technological capabilities which mean that we don't have to.

Going back far enough to when homo sapiens didn't have even the thinnest veneer of "humanity", such imperatives would have been a luxury - procreate before you die. Not that I am suggesting that there would have been no such thing as taboo.

Meatyfool..

[BobbyD]

The only thing i can think of for the female biological clock's cut off-point to be at a relatively young age compared to the male ability to produce which can continue for much longer is that perhaps nature doesn't intend males to be monogamous?

BnC

Childbirth is a significantly bigger risk factor for women than for men. Older women suffer increased risk of complications whilst not offering the best chance of strong and healthy offspring, they do offer other potential survival benefits to their group.

[Bminusrob]

My questions are (1) why when the natural life-span is at least 100 years does the female biological clock have a relatively short a period of time for compared to the male ability to reproduce.

I think the big mistake is the suggestion that the natural lifespan is 100 years. This link (https://en.wikipedia.org/wiki/Life_expe ... 0-2050.png) shows that as recently as the 1950's, even in the developed world, life expectancy was only about 65, and worldwide, it was only about 50. So, assuming a child needs a family environment for 15 years, this means that a woman needs to have her children by the age of 35.

Already, we are seeing women giving birth well into their 40's or even 50's, but nature does take time to catch up.

[madhatter]

I have also wondered about the relatively long period human children require before being able to do useful (for society) things. Can it be put down to being in the ecological niche that requires them to have to learn a lot of things that may be instinctive in other critters?

Having lots of read/writable brainpower instead of being born with mostly read-only memory?

Of course there are certain crows etc which seem very good at learning, but they don’t have hours of aeronautics lectures before learning to fly, do they?

Perhaps the brain size at birth is governed by the mother needing to survive the experience with at least the possibility of not minding having another go, but the brains “arms race” with other species of near human required increased development after that, along with the flexibility of needing to learn stuff which might otherwise be instinctive, leading to use of fire, stone axes, leaf shaped arrowheads, et-bleeding-cetera?

[Alaric]

This link

Be very careful about reading too much into life expectancy at birth.It's a useful composite measure but in terms of how long someone who makes it to adulthood will survive it's not so useful. By way of an extreme example, if half of all babies die shortly after birth, but the survivors live to 80, life expectancy is going to come out at 40.