In all of the biology that humanity has pieced together, a copious number of unresolved mysteries still exist, and aging is one of the more perplexing ones. Experts believe it is a multifactorial process and may involve several mechanisms working collectively, which results in humans and other organisms aging over time.
Scientists have proposed numerous theories that significantly overlap each other in some way, explaining the different aspects of aging. Here are a few of the most popularized:
- The genetic theory of aging predicates that the longevity of an organism is greatly determined by its genetic blueprint. One aspect of this theory of aging is telomeres. Segments of DNA that occur at the end of chromosomes, named telomeres, can estimate the maximum lifespan of a cell. Each time a cell divides, telomeres shorten. As telomeres become shorter, cells arrive at a point where they can no longer divide without sacrificing crucial segments of DNA, leading to cellular senescence. Genetic factors can influence the rate of telomere shortening, impacting the aging process at the cellular level.
- Programmed theories of aging state that senescence is an innate and essential part of an organism’s life and that aging is programmed into our bodies. The evidence to support this theory is that over the years, there hasn’t been a significant amount of variation in the lifespans of organisms. For example, elephants live an average of 70 years, whereas spider monkeys have an average lifespan of 25 years. Aging purposefully occurs due to evolved biological mechanisms to acquire evolutionary benefits. There are three main systems connected to this theory of aging: the endocrine system, the immune system, and the genetic system.
- The ‘Wear and Tear’ theory, also known as the ‘Simple Deterioration’ theory, suggests that senescence occurs due to the gradual damage to cells, essentially the “wearing out” of bodies over time due to use. This theory is categorized under the error theories of aging–which go against the claims of the programmed theories– they view aging as an occurrence due to a series of accidents instead of being programmed in the body. A wide range of factors are considered to accidentally damage the body over time such as exposure to radiation or toxins that damage genes. Even bodily functions cause damage over time due to their constant operation.
Along with these theories related to our biological system, several environmental factors may have a significant effect: diet, physical exercise, stress, and even social interaction have proven to exhibit major impacts on shaping the aging process.
There is no one explanation as to why aging exists; instead, several theories have been combined to explain different aspects of aging. This is what makes this complex phenomenon astounding.
- Anushka Jain
Sources:
- https://www.verywellhealth.com/the-genetic-theory-of-aging-2224222
- https://www.biomolther.org/journal/view.html?uid=81&vmd=Full
- https://www.verywellhealth.com/programmed-theories-of-aging-2224226
- https://www.physio-pedia.com/Theories_of_Ageing
- https://link.springer.com/referenceworkentry/10.1007/978-3-030-22009-9_731
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