After the wear and tear causes too much damage to our body to sustain, death occurs. With age, the body also loses its ability to damage repairs and combat diseases.
Our body is subject to abuse by external elements and also by usage. Definition There are various theories of aging, out of which, the 'Wear and Tear' theory of aging suggests that, human beings are simply like assets, and the cells of our bodies are subject to wear and tear.
There are various external agents, such as chemicals, ultra-violet rays, harsh climate, etc. In addendum, there can be various other reasons, such as smoking and over consumption of alcohol, that can add to the damage done to the body.
Lifestyle and over usage may accelerate the frequency of damage to the body. In short, this theory suggests that aging in humans is due to the degradation which the body is subject to. Let's see some examples to elaborate this biological theory of aging. Examples Skin The skin is the most delicate and exposed part of the human body. Apart from weather, sunlight, bruises, pregnancy marks, etc. With age, there is thinning of the epidermis, and it appears more wrinkled. Bones Bones undergo degradation too, and with age, there are many who complain of osteoporosis weakening of the bones and osteoarthritis pain and stiffness in the joints.
With efflux of time, our muscles tend to contract, thereby losing mass. Further, we suffer from joint pains due to increase in tensions. What is stopping a mouse or human from continuing those activities longer? Some organisms apparently do not age see Negligible Senescence. How do they avoid the supposedly inescapable deterioration? Some organisms, rather than dying from gradual aging, die suddenly following reproduction. Wear and tear does not provide an explanation for limited life span in these species.
Because of these major problems, few biologists currently believe in simple deterioration or wear and tear theories of aging. Note that while many scientists believe oxidation and other molecular damage are implicated in the aging process they also believe that other factors are involved in determining whether that damage is or is not repaired.
In summary, the simple deterioration theories are too simple to explain the multi-species observations and a more complex explanation is needed. This led to the development of more complex aging theories. All of the modern theories involve modifications to Darwin's survival of the fittest concept!
Modern Aging Theories In Sir Peter Medawar originated the now generally accepted idea that the force of evolution declines following the age at which an organism can complete a first reproduction because of attrition under wild conditions. For example there would be essentially zero evolutionary force toward having the internal ability to live longer than age X if essentially zero individuals live longer than age X in the wild because of external limitations like predators, intra-species combat, lack of food or habitat, harsh environmental conditions, or infectious diseases.
This idea led to modern non-programmed aging theories to the effect that each species only evolved the necessary maintenance and repair capabilities needed to support living to a particular age that was dependent on age-at-puberty, predation, and other species-unique factors. This idea provides a good match to the huge differences in observed species lifespans. Beginning in multiple population-benefit theories of evolution appeared to the effect that an organism trait that increased the ability of a population to avoid extinction could evolve despite being somewhat adverse to the survival and reproduction of individual members of that population.
These theories provided an explanation for observations such as animal altruism and sexual reproduction that appeared to be incompatible with traditional survival-of-the-fittest evolutionary mechanics theory. The cross-linked theory of aging, this theory follows the basis of that with age, the proteins in our body, our DNA and other structural molecules in our cells develop over time inappropriate attachments or a more appropriate name cross-linked. These bonds can inhibit protein enzymes breaking them down so these damaged cross-linked proteins stick around.
As they are in the cell and cannot be broken down, they can then cause problems and therefore they can lead to cell damage, which can lead to aging. For example cross-linking of the protein collagen ahs been shown to cause wrinkles which is a common sign of aging.
Finally, wear and tear is highly individualized. What is stopping a mouse or human from continuing those activities longer? They all suffer from corrosion and mechanical wear.
Just like a pair of socks, they can only last so long before becoming threadbare or getting a hole. Because of Medawar's modification, there existed an age at which the benefit of living longer was outweighed by the population benefit of limiting individual lifespan. As we get older the body produces lower levels of hormones which can have serious effects on our functioning. Note that while many scientists believe oxidation and other molecular damage are implicated in the aging process they also believe that other factors are involved in determining whether that damage is or is not repaired. Therefore, changes in the organs actually start at the very smallest unit which is at the cellular level. With age, there is thinning of the epidermis, and it appears more wrinkled.
What is stopping a mouse from continuing those activities longer? From birth we are equipped with a unique genetic code, which has a great deal to say about how quickly we age and how long we live. A Word From Verywell Rather than bore you with yet another admonition read: yawn to eat well and exercise, we offer one special tip from Verywell. This states that as people age, it is very important for them to be engaged in various activities and social roles. In very similar species such as mammals, the cellular and molecular basis of the organism is very similar and yet mammal life spans vary over a range of between Argentine desert mouse and human. With increase age, there is decrease body resistance to microorganisms such as virus and bacteria that cause diseases.
If we were to buy a new automobile or other complex machine, we might expect some immediate problems actually referred to as "infant mortality. Because of these major problems, few biologists currently believe in simple deterioration or wear and tear theories. Because of these major problems, few biologists currently believe in simple deterioration or wear and tear theories of aging. The obvious maintenance activities described here are all relatively short-term in nature weeks. Because of reduced immune response, the bactericidal effect of urine also decreases which allows invading microorganism to settle in the residual urine and multiply giving rise to urinary tract infection.
All the cars have deteriorated exterior paint.
These theories also called simple deterioration theories are attractive to many people who are mainly concerned with human aging but have severe problems as described below. If we then abandon the ship, it will eventually return to its original un-ordered, un-structured state: a large lump of iron oxide buried in the ground. Bifulco Throughout this semester we have come across many psychological and social theories. Does our human body suffer, too and age due to wear and tear? Aging as a Genetic Process in 3 Pages Words There are several theories on aging in humans due to genetics.
There is quick recovery from illness due to prompt and aggressive immune response. Simply using the organs over time wears them out even if you never touch a cigarette or have a glass of wine and stayed out of the sun, etc. The stream of urine also declines due to decreased bladder tone which facilitates the excretion of urine from the bladder.
Visually, we can find structural changes with age in our skin and bones. Then go and have some fun!
After the wear and tear causes too much damage to our body to sustain, death occurs.
In summary, the simple deterioration theories are too simple to explain the multi-species observations and a more complex explanation is needed. Another argument against the wear and tear theory notes that organisms in their growth phase become stronger and stronger. Apart from weather, sunlight, bruises, pregnancy marks, etc. The obvious maintenance activities described here are all relatively short-term in nature weeks.