Jakob BC wrote:
I'll have to disagree here. Of course +30-40 degrees C is too much for the human body, but we wouldn't survive long in minus degrees. Clothes is something else. In cold weather, the clothes helps us, If the human body was built to survive cold weather, we would wear fur. If it's possible to walk around naked outside without feeling too hot or cold, it's the perfect weather
You raise an interesting point,but you need to look into the Course of Evolution and mammals and humans adapting to conditions over the centuries,this will counteract the point you raise,there is a reason why you don't need a full coat of fur,but we do have a form of fur which acts as a semi coat,as when we are cold the Hairs on our body stand on end to trap air between the hairs to create a barrier which traps heat from our bodies.Over millions of years this coat on our bodies became less and less useful and through gene pools during breeding filtered our body makeup as we became more accustomed to surviving in less extremes so we needed less fur/Hair and began to use our Knowledge of covering our bodies to keep us warm,it didn't happen overnight it took thousands of years of evolution.
If you look at the history of Evolution and Living mammals,if we descended from Apes,you can see how we have adapted our exterior to cope with the different extremes,we can change our physical side of things by process of coping and variation and Genes,which would take thousands of years to actually evolve,we are as history would have us beleive to have descended from the Water,scientists have proved this yet whilst we have no form of fins or scales,and are not equipped to survive in the water for long periods this is how evolution works,we came onto the land and slowly over thousands of years changed our forms and limbs due to having to adapt to the Conditions and the needs to Survive
Your right in that we cannot cope in sub zero temperature extremes because we have adapted to the climates of the places we can inhabit,those places where we cannot inhabit we rely on Technology now to allow us to do so,if we were to face another Ice age,if we had not got the technology to aid us then I'm sure over a course of thousands of Years our bodies would change Form to allow us to do so,but it would be doubtful with the knowledge we have now that your going to walk around Naked in such Temperatures but we are of a high Intellect as Human Form so we use our brains rather than a process that Animals use of instinct and evolution and Gene selection
Chickens are supposed to have been a direct evolutionary descendant of T-Rex,if you look at their body forms and features,its somehow scarily believable and even more so when Chickens share the same DNA make up as the Dinosaurs,if you beleive the story of the Dinosaurs being wiped out by a meteorite then you'd find it hard to beleive the connection between a common Bird and a Dinosaur that roamed the earth Millions of years ago but you could see how the T Rex over time could have through its evolutionary adaption changed its form of short stumpy hands/Claws into a wing to adapt to different needs and situations to find food and survive
We no longer need to face the extremes so we slowly over time lost the need of an exterior coat,the same with most of the Animal world,they change form,through evolution based on the conditions and availibility of food or they die or become extinct altogther,
People who live in Sun drenched countries,there Skins have adapted to have less colour pigments because they need more sun protection than those people who live is less milder climates,hence why those people tend to be of darker complexion or black
I've always beleived in the Evolutionary stages,as its all around us,from the beggining of time history has showed us,in every living object you can see how they have changed form to survive and those that didn't became extinct,most animals by instinct adapt to their conditions.I do beleive that we as a human form cannot evolve anymore because we use and rely on Technology and Invention to help us face the extremes but this will also be our downfall,whilst we are intellectual,we cannot decide and control how the course of Nature works we merely try to adapt and relying more on Technology we are less able to Evolve naturally
Just to give you an example of how we can change form in our day and age,through conditions and adaption of our surroundings.it is predicted that because of the use of Mobile Telephones text messaging and more and more people utilising keyboard and phones pads that if this is a technology that is around for many hundreds of years over the course of selection and variation we will breed through our genes,the average thumb length and finger length will have drastically shortened due to the way in which we utilise our hands in such day and age
, I could barely tolerate -8°C a couple of weeks ago. 
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