This presentation deals with how do we age and why do we age as the time passes. There are multiple theories which are discussed about the ageing and some evolutionary trade-offs. The evolutionary theories are divided into Programmed theory and damaged or Error theory. Also the evolutionary tradeoffs discuss about how some evolutionary changes help or cause problem to a particular species.

1. AGEING AND EVOLUTIONARY TRADE-OFFS
NAME: ABHISHEK ANAND SHETYE
CLASS: M.SC. MICROBIOLOGY PART 1
GUIDING TEACHER: MRS. SHITAL SHEVATE

2. 1. WHAT IS AGEING?
• Ageing is the result of the progressive accumulation of the changes in the
body which occur with the passing of time, causing the increase in the
probability of disease and death of individual.
• It can also be defined as wearing of the structures and functions that reach
a peak or plateau during development and maturation of the individuals of
a given species.

3. 2. THEORIES OF AGEING
• Despite recent advances in the molecular biology and genetics, the mysteries that
control human lifespan are yet to be unraveled.
• Many theories have been proposed to explain the process of ageing but neither of
them appears to be fully satisfactory.
• Modern biological theories of ageing in humans fall into two main categories:
A. Programmed theory and
B. Damaged or error theory.

4. A. PROGRAMMED THEORY
• The programmed theory has three sub-categories:
1. Programmed longevity:
• Aging is the result of a sequential switching on and off of certain gene.
• Senescence being defined as time when age associated deficits are manifested.
2. Endocrine Theory:
• Biological clocks act through hormones to control the pace of ageing.
• Recent studies confirm evolutionary conserved Insulin/ IGF-1 signaling pathway plays
key role.

5. A. PROGRAMMED THEORY
3. Immunological Theory:
• Immune system programmed to decline over time, leading to increasing
vulnerability to infectious diseases and thus ageing and death.
• It is researched and documented that effectiveness of immune system
peaks at puberty and gradually decreases with the advancing age.

6. B. DAMAGE OR ERROR THEORY
• The Damage or Error theories emphasizes environmental assaults to living
organisms that induce cumulative damage at various levels as the cause of ageing.
• This theory include:
1. Wear and tear theory.
2. Rate of living theory.
3. Cross linking theory.
4. Free radical theory.

7. B. DAMAGE OR ERROR THEORY
1. Wear and tear theory:
• This theory was put front by Dr. August Weismann, a German biologist in
1882.
• This theory sounds perfectly reasonable to many people, because this is
what happens to most familiar things around them.
• This theory states that Cells and Tissues have vital parts that wear out
resulting in ageing.

8. B. DAMAGE OR ERROR THEORY
2. Rate of living theory:
• This theory was proposed by Dr. Rollo.
• This theory is not completely adequate in explaining the maximum life span.
• This theory states that the greater an organisms rate of oxygen basal metabolism,
the shorter its lifespan.

9. B. DAMAGE OR ERROR THEORY
3. Cross-linking theory:
• Cross-linking theory was proposed by Johan Bjorksten in 1942.
• According to this theory, an accumulation of cross-linked proteins damages the
cells and tissues, slowing down bodily processes resulting in ageing.

10. B. DAMAGE OR ERROR THEORY
4. Free Radical Theory:
• This theory was first introduced by Dr. Gerschman in 1954, but was
developed by Dr. Denham Harman.
• This theory proposes that superoxide and other free radicals cause damage
to macromolecular components of cell giving rise to accumulated damage
causing cells.
• This eventually leads organs to stop functioning.

11. 3. EVOLUTIONARY TRADE-OFFS
• Trade-off:- A trade-off is a situational decision that involves diminishing or
losing one quality, quantity, or property of a set or design in return for gains in
other aspects.
• In simple terms, a trade-off is where one thing increases and another must
decrease.
• Evolutionary Trade-off:- A situation that occurs when a change in one trait
increases fitness, but a simultaneous change in another trait reduces fitness, thus
preventing the organism from optimizing both changes.

12. 4. EXAMPLES OF EVOLUTIONARY TRADE-OFFS
1. Shrimp like species:
• Chaundianella ovata and Waptia
fieldensis two closely related
Cambrian arthropods.

13. 4. EXAMPLES OF EVOLUTIONARY TRADE-OFFS
2. Peppered moth:
• Biston betularia f. typica (White
bodied pepper moth) and Biston
betularia f. carbonaria (dark
bodied pepper moth).

14. VIDEO

15. REFERENCES
• https://pubmed.ncbi.nlm.nih.gov/11089980/
• https://phys.org/news/2020-04-evolutionary-tradeoff-ancient-shrimp-like-
species.html#:~:text=Prior%20research%20has%20shown%20that,offsprin
g%20a%20species%20may%20produce
• https://en.wikipedia.org/wiki/Peppered_moth_evolution
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995895/

16. THANK-YOU