Why the human body gradually falls apart

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Last week on the ABC's The Science Show they broadcast a press conference type Q&A on "Why the human body gradually falls apart"

Full transcript as well as podcast available here

 

why do humans have an arch?

 

It's OK to say that, in terms of designing or re-designing the body, you wouldn't start from 'here' but given that 'here' is exactly where we are it's interesting to speculate on the advantages as well as disadvantages that come from the Duct tape and paperclip approach (Duct tape and paper clips being the evolutionary successors to a bit of string, which was itself successor to a thinly cut strip of hide, etc)

What is the survival advantage (for the species) of having a body that gradually falls apart?

Does sticking on more Duct Tape and paper clips necessarily improve the survival prospects?

Is there any way of knowing, in the short term, if there is a long term survival advantage in any tinkering that humans do with their internal or external environments?

Bill

PS Just an idea to try and prevent any thread that uses the word evolution from being side-tracked or swamped by 'anti-evolutionsts'.

How about the 'anti-evolutionists' starting a thread with the same title as the above but with the addition (anti-evolution), ie Why the human body falls apart (anti-evolution). That way each group can happily develop their separate arguments and those who have a foot in either camp can compare and contrast and hopefully get the best of both worlds.

Lead balloon?

 

For the species, it is surviving until you can reproduce, so after that your body can fall apart, but your genes will go on, flawed as they maybe.

Public health initiatives (clean water, vaccines etc.), Modern medicine and surgery as well as improved food security, have all lead to an increase in life expectancy over time, though, for the current generations, in the developed world, average life expectancy is likely to decease, due to the obesity epidemic.

and I agree with your concerns and suggestions re controlling the threads responses.

 

Duct Tape and pape clips or not, the prosthetics still have a long way to go to better the human foot. I have quite a number of young male patients with prosthetics and none of them would choose their prosthetics over what they had before, although many had elective amputations as they would rather have a prosthetic than their injured foot. Those that do multiple tasks have different prosthetics to do them. One for running, another for hill walking and a third for normal street walking. Healthy human feet do it all. Another aspect of design is cost, below the knee coming in at about £40 grand and above the knee about £60 grand.

Stephen, a factor that is significant after we reproduce is our ongoing ability to care and nurture for twenty years or so. An important part of that is the presence of grand parents who can markedly increase the child's chances of survival. Children whose genes will enable them to become grand parents will themselves be more likely to have grand parents and so may be more likely to survive. Just a thought beyond simple mechanics.

 

Absolutely Bill and that, sadly, might well be the reason why grandfathers in general, die before grandmothers, ie the survival advantage to the children and grandchildren of a living mother/grandmother goes on longer than the survival advantage of a living grandfather. Although in contemporary society we have almost dissociated the role of grandparents in survival of grandchildren.

Bill

 

Interesting Stephen.
However, I would suggest that merely because us "mortals" would not design a foot the same if we were to start over, doesn't mean that there is a better way nor does it mean that we, with all our intellect and biomechanical training, could do a better job than evolution or God.

For instance, if you have tried to walk on a "blade" (similar to a blade prosthetic) it works fairly well with straight locomotion on a flat surface, but try it on uneven ground, pivoting, balancing on different areas of the weightbearing surface...it is not so perfect. If it was biological, I'm sure it would be painful as well. When broken or damaged, it doesn't heal very well either (that's a joke)



Steve

 

Jeremy de Silva says that '........ humans are not perfect because evolution doesn't produce perfection...'

Where did the notion of perfection come from?

Surely evolution should be judged on the basis of 'fit for purpose' rather than some manmade, poorly applied idea of perfection?

If 'fit for purpose' means able to reproduce and to ensure that each generation has the maximum/optimum opportunity to reproduce then man is certainly fit for purpose, so far and is in that sense 'perfect'. The focus of 'fit for purpose' or 'perfection' is not the individual but the species. Individuals only become important if too many of them are, one way or another, interferring with the 'reproductive purpose'.

Its OK thinking about useful evolutionary changes as those changes that match man to his environment and focusing on how man is changing but it is equally important to think about how man is producing evolutionary change upon his environment.

The more man actively alters his environment to 'suit' him the less able man becomes to survive in a 'natural' environment. Therefore the more environmental control man exerts the more he needs to exert and the greater the risk of getting it wrong in a big way.

Bill

 

Stephen and Colleagues:

I believe that the main point of the effects of aging on the human musculoskeletal system has been missed by the comments so far. There is plenty of scientific evidence that shows that, over time, there is a degradation in the mechanical characteristics of the structural components of the body over time, with aging. Ligaments and tendons become less elastic and more likely to tear when subjected to tension forces with age. The bones become less dense and more resistant to fracture with age. The hyaline cartilage in our joints is subjected to imperfect applications forces and moments across them so that joint surface wear and tear occur over time with aging. Muscle mass decreases due probably to changes in hormonal patterns with aging. Central nervous system function deteriorates with aging as the patterns of neural cell alterations change over time. The list goes on and on.

Here is a very sobering study for those over 30 years of age who think that aging is not affecting themselves, and their patients, every year of their lives:

Contrary to the headlines seen in the popular media, the effects of aging on our bodies and other animals has been extensively studied and there is no real mystery as to why the "human body falls apart". All animals are affected by the aging process and this is part of the natural process of all members of the animal kingdom. Once one reads the scientific literature on the subject, one will find that we can only delay the inevitable: over time, we will all deteriorate. Aging is as just as normal as living and dying.

These facts give even more reason to make every day count in the lives that we have been gifted with in the short time that we all have on this wonderful planet.:drinks

 

Yes, I absolutely agree with all of that Kevin, especially the last sentence. However there seems to be something happening here that is very different from the deterioration of say a car, which is directly in proportion to its use and exposure to the elements.

It seems that all creatures have evolved to age and die at specific rates. It is as though it is of benefit to the species as a whole that the individuals pass away, in the case of humans, after 70 - 100 years. Not only that, it seems of benefit to the species, that individuals display their age regardless of their lifestyle as being young and strong, middle aged and powerful, and old and carriers of the collective wisdom.
We see this in cells where the mitochondria are programmed to self destruct the cell and if they fail to do so, the cell becomes a cancer.

 

Jerry De is a good boy. Bernie Zipfel (ex head of school of podiatry in South Africa, before he got lost down the same pathway as myself), and myself have written a few papers together, including one in Science. It just shows you the modern world of technology: we live on 3 continents, I have never met Jerry...............

 

But then it's highly probable that you (and the vaste majority of others) would say that as such a belief undoubtedly has a significant survival advantage. You are constructed by evolution to view life as a 'gift' and this planet as 'wonderful'.

With the gradual falling apart of your (in general) human body it is quite possible, for many of us that a time will come when 'gifted' might be replaced by 'burdened', for example and 'wonderful' by 'maligned'. Neither position would be objectively true but each is probably influenced by evolution.

Bill

 

Having now the experience of raising two boys, that are now men, and now having three grandchildren (ages 6, 5 and 3) hanging around our house a few days a week, one can certainly appreciate the positive influence that grandparents can have in the development of their grandchildren. Possibly the survival rate does not appreciably increase with exposure to influence and care of grandparents but the ability to impart accumulated wisdom to and help with the raising and care of grandchildren by grandparents seems to be quite an obvious benefit of having grandparents around to help grandchildren. Unfortunately, I never knew any of my grandparents, and I wonder how such an influence would have changed my life.

The aging process certainly diminishes the physical potential of all of us, but with aging, also comes the wisdom of experience. I appreciate this wisdom now at age 56, but sometime wish I had the physical abilities I did when I was 25 years old.

Possibly......this is part of the grand design of the human.....not giving all the best things of life to them at all the same time.....?