[gurpal (OP)]

How do human bodies respond to changes
inside them and to their environment?

[carreerslut]

Three ways I can think of

1.  We change our behaviour eg. put a coat on if it is cold.

2.  We change our physiology eg, redistribute our blood supply and generate internal heat by shhivering if is cold.

3.  We change our environment to suit us eg start a fire or turn up the thermostat on the central heating if we are cold.

Right now I am hot, in temperature that is.

[Nizzle]

Saliva production is triggered by smelling odours associated to food

The stomach produces higher volumes of digestive fluid when food is inside

adrenaline levels in the blood rise when in danger

You yawn if your blood oxygen level is a bit low

you sneeze when there are too much outside particles in your nose

you sweat when it's too hot outside

you melt/catch fire when it's getting even hotter

your insulin level rises when your blood sugar level is high

and i can go on and on but i don't feel like it []

[lyner]

All the above mechanisms could be described as contributing to what is called homeostasis. This means maintaining our internal body conditions.
However, I suspect that the OP may have been hinting at evolutionary changes. That is a whole new ballpark. There seems to be no way in which organisms can achieve genetic changes simply because they 'would be' an advantage. Of course, humans have now that capability so we could actually envisage growing oun necks long because we wanted to reach up into trees or grow long coats of beautiful hair.

[Don_1]

I interpretted the question the same as sophiecentaur.

Answer #3 given by carreerslut pretty much sums it up, we have an ability to change our environment to suit us, in many ways, therefore, we do not need to evolve to meet the requirements of our environment.

To use sophiecentaur's example of needing to reach high into a tree to pick the fruit, why would we need to grow a giraffe like neck or limbs better adapted to climbing? All we need do is invent a ladder.

As for changes inside our bodys', I'm not sure what you mean. The internal balance control is as carreerslut & Nizzle said, already dealt with by the body's various regulatory systems. But as for other responses to 'changes inside them', I really can't think what sort of 'changes' you are suggesting might happen, which are not changes instigated by our own body in the first place. Unless you are referring to bacterial/viral/parasitic attack, in which case, the defence mechanism goes into action, or we take drugs.

[Nizzle]

Aha, evolutionary changes inside the human body.

The appendix is assumed to serve no purpose and people don't know why it's there. This might be an evolutionary leftover of a much longer gut that our ancestors needed to digest the plants from that time period.
The coccyx bone is left over from our ancestors' tail, which we didn't need anymore when we came out of the trees and into the plains.

Other more recent changes are an enlarged cranium and an ever smaller mandible, caused by the need for more brain, and the fact that we prepare our food which makes strong jaws less important.
Our thumb muscle strength compared to index finger muscle strength is also increasing on average over generations.

[Don_1]

Other more recent changes are an enlarged cranium and an ever smaller mandible, caused by the need for more brain, and the fact that we prepare our food which makes strong jaws less important.
Our thumb muscle strength compared to index finger muscle strength is also increasing on average over generations.

This suggests that our index and middle finger will become more pronounced due to left and right 'clicking' and use of the scroll wheel. This could have another advantage.....

As for the jaw becoming smaller, I can site 'er indoors as irrefutable evidence that this is not the case, 'er jaw wags all the bloody time... a never ending torrent of ...... Ooer, look out! Here she comes now, I'm off

[lyner]

I think the argument is taking us in to Larmarkian regions. Discredited many years ago, I'm afraid. Evolution is a lot more complicated than that.

[DoctorBeaver]

There are several examples of the human body changing to better suit the environment. One of the most obvious is the fact that Inuit have no facial hair. Frost tends to stick to beards & moustaches and even though you may think that a beard would act as insulation, it actually works in the opposite way. I can't, however, explain why Inuit are not bald. I also seem to recall reading somewhere that the teeth of Inuit are slightly different due to the high proportion of fish & blubber in their diet.

Another example is the increased lung function of those who live at high altitude. Lung function can be increased by moving to higher altitude (hence the benficial effects of high-altitude training for athletes) but will never reach the level of that of natives.

But the most striking example is that of skin colour. As Homo Sapiens moved out of Africa into cooler climes, skin lightened in colour.

[lyner]

But, Dr B, that isn't explained by Lamarkian effects. Those are pretty straightforward 'selective' effects. Remember - it isn't necessarily "survival of the fittest", it's survival of the ones that reproduce most effectively.
Along with Lyre Birds and Stags - the chicks may just prefer hairless guys (possibly an inappropriate characteristic for survival) under certain conditions.

[Variola]

See now I read this question as more of a physiological one, i.e how do we respond to a sudden change in temperature, we sweat or we shiver and divert blood flow etc.
How do we respond to changes inside ourselves, I view as a homoeostasis  question, which has already been partially covered by Nizzle.

Hmmm how to baffle the TNS forum...  [] []

[DoctorBeaver]

I do apologise, SC. I was under the mistaken impression I was replying to the original question; to whit "How do human bodies respond to changes inside them and to their environment?".

[Variola]

I do apologise, SC. I was under the mistaken impression I was replying to the original question; to whit "How do human bodies respond to changes inside them and to their environment?".

That makes two of us who thought that then.

[RD]

... Inuit are slightly different due to the high proportion of fish & blubber in their diet.

[Albert (old man) Steptoe voice]  "Inuit, terrible bleeders" ...

 [ Invalid Attachment ]
http://books.google.co.uk

[Perhaps this anticoagulant effect is an evolutionary countermeasure by the seals & fish to sabotage their predators].

[lyner]

I do apologise, SC. I was under the mistaken impression I was replying to the original question; to whit "How do human bodies respond to changes inside them and to their environment?".

Cross purposes again Dr B. We must stop meeting like this! [:I]

[DoctorBeaver]

I do apologise, SC. I was under the mistaken impression I was replying to the original question; to whit "How do human bodies respond to changes inside them and to their environment?".

Cross purposes again Dr B. We must stop meeting like this! [:I]

The neighbours are already gossiping.