1. Theoretical Perspectives on
Aging
By: Cody Harman
TRMT 392
Special Topics: Seniors
David Robinson, PhD.
May 17, 2010

2. Contents
1. Overview of Aging Theories 11. Interconnectedness of
2. Overview of Aging Theories Aging factors
3. Overview of Aging Theories 12. My Opinion
4. Overview of Aging Theories 13. References
5. The Beginnings of Aging
Theory
6. Medawar’s Theory
7. Medawar’s Theory
8. Programmed Aging Theory
9. Non-Programmed Aging
Theory
10. Physiological System Theory

3. Overview of aging theories
• Programmed Aging
– Theories that posit that the human condition is a
``programmed`` process
– According to the Programmed approach, the
inherent repair and renew processes of the
human body means that without genetic
purpose for aging, our bodies could live without
aging.

4. Overview of aging theories
– “...aging and death, according to this theory, are
not a result of wear and tear or exposure, but are
a programmed, natural and necessary part of
genetics. In short, we are programmed to age and
die. “(Stibich, 2007)
– Evidence for programmed aging is shown by
many things, including the average age of death
within a species (elephants around 70, people
average 80 years) (Stibich, 2007)

5. Overview of aging theories
• Non-Programmed Aging
– Theories that posit ideas of aging due to issues of
wear and tear, not through purposeful genetic
programming
– Wear and tear theories are based on older, less
developed ideas of evolutionary mechanics.
– Also called passive or non-adaptive, these theories
contend that aging is actually adverse to
populations
(Azinet LLC, 2010)

6. Overview of aging theories
• Physiological System Theories
– Theories which suggest that aging is not the result
of either programmed or passive systems, but the
result of failures in certain body systems causing
bodily harm
– Physiological theories actually have influence from
basic cellular deterioration theory, as well as the
inter-connectedness of different biological
systems in the human body
(Lakehead Education, 2005)

7. The Beginning of Aging Theory
• August Weismann, German evolutionary biologist, suggested a
Programmed Death Theory. Programmed Death suggested that
death is an important and required step in Darwinian evolution.
Without death, younger (more evolved) members of a species
would be required to contend for sustenance with older (less
evolved) species members. This theory is supported in basic theory
by modern advances in evolutionary mechanics. (Azinet LLC, 2009)
• Darwin`s On the Origin of Species, changed the entire conversation
regarding aging. Prior to it`s publication, aging was believed to be
part of the design of a species. No explanation was needed, as
general opinion was that a creator designed the species. After
publication, Darwin spoke of aging, saying “...there must be some
hidden benefit to a limited life span that compensated for its
otherwise adverse nature...” (Azinet LLC, 2009)

8. Medawar’s Theory
• Medawar's Hypothesis on Mammal Aging
– One of the earliest theories regarding the relatedness of
population size and age. Combined ideas from both Weisman
and Darwin.
“Medawar proposed that even if an animal did not age, that is, did not have
an increased probability of death as a function of age, the numbers of adult
animals of any given age would decrease exponentially because of deaths due
to other causes such as predators, environmental conditions, etc. Some
constant percentage of the animals of any given age would be killed in any
given time period. As a metaphor, he used the random breaking and replacing
of test tubes. If, in a lab with hundreds of test tubes, when a test tube is broken
it is replaced with a new (age = 0) test tube, then after a while the number of
test tubes of a given age in the test tube population will decline exponentially
with age.”
(Azinet LLC, 2009)

9. Medawar’s Theory

10. Programmed Aging Theory
• Error Theory
– Error Theory suggests that aging is not a process
of DNA, but actually RNA errors that result from
poor transmission during the copying process of
cell splitting
– This incomplete copy therefore cannot function as
the original cell did, causing cellular breakdowns,
deterioration, and eventually death in the host
(Lakehead Education, 2005)

11. Non-Programmed Aging Theory
• Wear and Tear Theory
– Suggests that the human body is similar to a
machine, and is susceptible to wear and tear in
much the same way that a car is (Azinet LLC, 2010)
– Damage is caused by toxins, radiation, ultra violet
light, and other environmental influences (Stibich,
2007)

12. Physiological System Theory
• Immunological Theory
– Suggests that aging is not a process, but more
accurately a disease of the immune system
– Immune system’s antibodies, which are supposed to
help protect our systems
– Antibody production peaks during adolescence, and
decreases from this early peak
– As antibody systems change over time, the body has
trouble telling apart required cells from mutant cells.
This effectively makes the human immune system it’s
own enemy
(Lakehead Education, 2005)

13. Interconnectedness of Aging factors
Image taken from Innovita Research (http://www.innovitaresearch.org/news/res/02071901_01.jpg)

14. My Opinion
Upon reading all of the material, researching, and compiling information, I have developed
my own opinions regarding aging theory. While many of the theories in each of the
categories (programmed, passive, physiological) are developed to offer an alternative to
other theories, I have an opinion that takes influence from all of the categories, and is an
attempt at looking more holistically at the aging process. The Error theory’s suggestion of
RNA replication errors offers a scientifically supported explanation of why cellular breakdown
occurs, and can also explain why it occurs more rapidly as our bodies age. The Wear and Tear
theory’s consideration of external influences in not cellular mutation is suggested as a
replacement to Error theory, but I feel that both Error, and Wear and Tear theories are
different paths to reach the same destination. I feel that cellular mutations the cause
deterioration are not the result of one or the other, but a combination of RNA errors and
external influences. Further, The Immunological system theory`s suggestion that immunity
breakdowns cause aging is, I think, a result of the Programmed and Passive theories. If the
cellular mutations experienced in these theories did not occur, then arguably the Immune
systems functions would still occur in the same way as they did during adolescence. This
would lead us to not age in the same way we age now. We would age, but functionally, we
would not deteriorate.

15. Further explanation and
understanding
• Aubrey de Grey, a biogerontologist from
Cambridge, is a proponent of “curing”
humanity of age related deaths. In this video
he discusses the potential to reverse aging.
Click his picture to open the video.

16. References
Azinet LLC. (2010). Wear and tear theories of aging. Retrieved from http://www.programmed-
aging.org/theories/wear_and_tear.html
Azinet LLC. (2009). Medawar's hypothesis on mammal aging. Retrieved from
http://www.programmed-aging.org/theories/medawar_hypothesis.html
Azinet LLC, (2009). programmed aging theory information weismann's programmed death
theory. Retrieved from http://www.programmed
aging.org/theories/weismann_programmed_death.html
Azinet LLC, (2009). Darwin on aging theory. Retrieved from http://www.programmed-
aging.org/theories/darwin_evolution.html
Lakehead Education, Initials. (2005). Biological theories of aging. Informally published
manuscript, Gerontology, Lakehead University, Thunder BAy , Ontario. Retrieved from
http://flash.lakeheadu.ca/~mstones/Biological%20theories%20of%20aging.pdf
Stibich, Mark. (2007, 3 28). Programmed theories of aging. Retrieved from
http://longevity.about.com/od/researchandmedicine/p/age_programmed.htm
Stibich, Mark. (2007, March 28). Wear and tear theory of aging. Retrieved from
http://longevity.about.com/od/researchandmedicine/p/wear_tear.htm