I wonder why the human body is so badly designed?

[LJ17xx]

However the human race came about, why are we so unprepared for life? Our bodies aren't equipped. So many illnesses, mental health disorders, too many ways to die!

There is no evolutionary advantage in being able to survive for a prolonged period beyond optimal child-producing age,

Ah there might be. For women at least. There seems to be a positive survival affect with engaged grandmothers. So having a decent granny around to help seems to improve infant survival. Doesn’t apply to men apparently but some hypothesise that this is one reason menopause evolved.
You see similar ‘alloparenting’ behaviour in many birds (the Seychelles warbler I think is one? I could be wrong on that it's a long time since I did anything on this...) anyway having an aunt or GP around helps the offspring survive. Even if the helper doesn’t pass their genes on directly, the young they help are sufficiently related genetically for there to be a positive selection pressure on what for want of a better word, is altruism.

You see similar ‘alloparenting’ behaviour in many birds (the Seychelles warbler I think is one?

And this is why I love MN

I heard a talk from a clinical psychologist recently who said that in evolutionary terms, are brains are still looking for - and coping with - sabre toothed cats. (Was in the context of stress and resilience)

Ah yes I was right...

en.m.wikipedia.org/wiki/Seychelles_warbler

I was working on sex allocation skewing rather than alloparenting - there’s some evidence that they can skew the sex ratio of their offspring to adapt to resource availability. Interesting birds anyway.

I’m available for pub quizzes.

And yeah, I want a new set of teeth every 20 to 30 years - if sharks can keep growing new teeth, why not us? Maybe we should start a campaign, I seriously hate the thought of false teeth and see the hygienist every 3 months without fail. All my kids have had teeth extracted, they've all had wisdom teeth out which I don't have and one has had extractions for orthodontic work. I hate the thought of having to have teeth extracted.

Well it is only supposed to last 35 years or so. When you at it that way one would say that we have managed remarkably well with our poorly evolved bodies considering that most people don't get properly ill until their sixties, often not until their eighties.

Because we came to be through evolution which is just a series of happy accidents

so many of my family have died from this way before their time

We probably aren’t supposed to live beyond 40. The vast majority do.

I heard a talk from a clinical psychologist recently who said that in evolutionary terms, are brains are still looking for - and coping with - sabre toothed cats. (Was in the context of stress and resilience)

Absolutely true. A fascinating subject.

I doubt the Americans would be funding nasa if most males could face the prospect of death or injuries at some time in life to carry on the species.

Guns. Kill (& hurt) mostly men. In USA. Civil society. Do you see any federal research to try to understand much less stop that?

Everybody known somebody who lived to 100 and smoked 60 cigarettes a day

I don't . I know just one person who got to 100 (non-smoker & tee-total). I know a few who got over 90 (all non-smokers, some tee-total).

My brother smokes about 60/day and is still alive, amazingly enough (age 59). He won't make 70, though.

Body: "I'm amazing! I'm just 9 months I can grow an entirely new human. Brain, body, the works."

Me: "Fantastic! How long will it take you to repair my bad back?"

Body: "Fuck you."

Everybody known somebody who lived to 100 and smoked 60 cigarettes a day

In genetics, this is called ‘the uncle Albert effect.’ It’s when people go ‘well, uncle Albert smoked fifty a day/snorted asbestos/drank a bottle of whiskey a day and rode mustangs blindfold so it CANT be bad for you...’

Some people are just lucky

Most people I know don't look after their 'vessel ' very well. I think a well looked after body and insides is exceptional .

I think I'm obsessed with teeth but wisdom teeth are surely a design flaw? My kids went through hell with them, were warned about nerve damage due to how the nerves were running through the roots but had them out anyway. Then one got dry socket and that was another load of hellishness. Definitely no point in wisdom teeth that I can see, mind you I don't have them so what do I know?

Everybody known somebody who lived to 100 and smoked 60 cigarettes a day lljjk I don't either. I don't think I've ever met a 90 year old either although both my grandfathers (both smokers one a drinker) almost made it.

My wisdom teeth came in with almost no trouble. My dentist would mutter at them as if to say "WTF are THOSE doing in your mouth?"

justanotherzombie No the human body isn't perfect. What's your appendix for? Your spleen? Why do you have a lower spine/lumbar spine so ill designed for modern upright walking? Why do you have unneeded wisdom teeth crowding your jaw?

Please illustrate your belief in human perfection.

Tansie1 - What's your appendix for? Your spleen?

Your spleen is pretty important. It's where infections that have reached the blood get trapped by immune cells. If you lose your spleen you're likely to develop sepsis from fairly common infections, which is why people who've had it removed have to have additional vaccinations and take life-long antibiotics. It's also where most red blood cells get broken down at the end of their useful life.

I don't understand how humans have evolved to require clothing to keep warm.

Or as a species have we simply moved too far away from our original stomping ground (Africa I think) where the weather is warmer?

I don't understand how humans have evolved to require clothing to keep warm.

It gives us flexibility: we can put clothes on or off, depending on conditions. Which is why human can survive almost anywhere in the world.

When I said 'everybody knows somebody...' I did not mean literally - the aforementioned 'Uncle Albert' effect is what I meant. It is often used to justify a terrible lifestyle but goes alongside a very poor understanding of the concept of 'risk': you can have a high risk of something happening and it doesn't, or a low risk and it does.

I find it quite interesting that there can sometimes be competing interests between the survival of a species' DNA and an individuals.
It's all rather fascinating.

Please illustrate your belief in human perfection.

Striving for perfection just sets you up to fail.
Biology/evolution does simply not care whether what she gets up to is convenient to the individual, and evolutions takes far too long to notice a significant difference in the lifetime of an individual.

Spleens - really important.
Appendix - give it a few 10.000 years and it may disappear
Wisdom teeth - ditto, although they do not bother everybody and may have had a use at some point in time.

Backpain - for the vast majority of simple mechanical backpain the only thing with any kind of chance of longterm improvement is the right kind of mobilisation, movement, stretches, strengthening of back-, stomach- and pelvic floor muscles - the famous 'core'. If we don't use the tool that is our body appropriately, we cannot really complain if it malfunctions

I don't understand how humans have evolved to require clothing to keep warm.

We haven’t evolved to do anything - that’s the important thing to keep in mind. Humans first evolved in a hot climate and we’ve spread massively since then in the blink of an eye in geological/evolutionary terms. And we are smart and can make clothes and it seems we have been doing so from VERY early in our history. So in a way clothes ARE part of our actual makeup. Just like tools. It’s not part of our body but we have the skills to make them, just like birds build nests and beavers build dams and other species create protective shells or bubbles out of found objects.

But in fact we have evolved some physiological tricks to keep us warm in colder climates. Neanderthals (and most non Africans have some Neanderthal DNA) had a larger body mass which would have had a more favourable surface area to volume ratio for heat retention. You also see real physiological adaptations in arctic populations - theres a ‘heat flush’ response in the extremities whereby vessels dilate briefly to flush the area with warm blood then contract again to regain heat. Shorter stature/limbs/stocky builds seem to also retain heat better.
Groups who have lived at altitude for long periods of time also develop adaptations- Sherpas for example and populations in the high Andes have mutations which allow more efficient oxygen transfer across the placental gradient from Mum to baby. If you take an American indigenous person from a sea level dwelling group and put them at high altitude or a westerner who is from a lowland group at high altitude they have all sorts of issues with high altitude pregnancy.

We do evolve and we are still evolving. The incidence of the cystic fibrosis gene is postulated to be the result of the Black Death plagues for example. If a terrible plague decimated us tomorrow, the survivors would repopulate and any advantageous resistance genes would spread.

It’s all fascinating stuff. I’m a geneticist and it’s so interesting because it combines science, physiology and also a lot of anthrology, history etc.

Skilltan- interesting about the spleen.

My DB had a splenectomy at 22. He's now 56 and has never taken additional drugs!

Wisdom teeth - ditto, although they do not bother everybody and may have had a use at some point in time. I always tell my kids I'm more evolved than them as I don't have wisdom teeth.

Our bodies aren’t designed, they have just adapted into what they are now. I think the human body is amazing and I’m in awe at its ability to self heal etc I do think since standing though our bodies are a bit crap at giving birth I think due to change of shape or birth canal and also larger brains overtime, but trying different positions can help with that. I think our bodies are still surprising us even today and forever changing.