Student Scholarship

Document Type

Research Paper

Abstract

The study of aging has historically transitioned from ancient folklore and mythical elixirs to the rigorous scientific discipline of gerontology. Throughout history, humans have attempted to recapture youth through practices ranging from the consumption of gladiator blood to the use of testicular extracts, though modern science has only recently begun to categorize these efforts into verifiable hypotheses. Gerontology defines true biological aging, or senescence, through four specific criteria: universality, intrinsicality, progressiveness, and deleteriousness. These benchmarks ensure that an age-associated change is a fundamental part of the biological process rather than a result of disease or environmental factors. 

Current biological research focuses on three primary theories. The first suggests that aging stems from changes in noncellular materials, particularly the accumulation of cross-links in collagen fibers. As these fibers become more tense and less elastic due to random molecular movement, they hinder the delivery of nutrients and the removal of wastes throughout the organism. The second theory attributes senescence to the loss of or injury to non-multiplying cells, such as neurons. While humans lose roughly 100,000 brain cells daily, this theory is often considered insufficient on its own to account for the total complexity of death. 

The most supported hypothesis is the somatic mutation theory, which posits that aging results from genetic alterations in multiplying cells. Mutations within the DNA double-helix are perpetuated through protein synthesis, eventually disabling the chemical reactions necessary for survival. Evidence for this genetic basis includes the finite life spans of different species, the limited division potential of human cells, and the observed heritability of longevity. While no single theory is exhaustive, the genetic perspective offers a comprehensive framework for understanding how cellular decay translates into the systemic failure of the human body.

Research Highlights

  • The Problem: The researcher examines the biological mechanisms of aging and evaluates historical and modern attempts to achieve longevity or rejuvenation against established scientific criteria. 

  • The Method: This study analyzes three classic theories—noncellular material changes, loss of nonmultiplying cells (neurons), and somatic mutations in multiplying cells—using the criteria of universality, intrinsicality, progressiveness, and deleteriousness. 

  • Quantitative Finding: Human brain cell loss is estimated at 100,000 neurons per day; most bodily functions decrease by 1% per year after age 30; a 30% decline in cardiac output severely handicaps an organism; maximum cell doubling generations are approximately 20 for chickens/rodents, 50 for humans, and 80 for Galapagos turtles. 

  • Qualitative Finding: Aging is characterized by an accumulation of collagen cross links due to Brownian movement; neural depreciation leads to diminished alpha waves and senile dementia; dietary restriction in rats can extend the period of youthfulness by slowing growth before maturation. 

  • Finding: The somatic mutation theory, which links aging to DNA/RNA damage and protein synthesis errors, is identified as the strongest possibility because it correlates most closely with the defined criteria for biological aging. 

Publication Date

5-1975

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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