SOME FACTS ABOUT AGING AND IMMORTALITY
Let us proceed to demolish superstitions. Is aging universal?
Clearly not. If everything aged, the continued survival of the
cells responsible for producing our sperm and eggs (the germ-
line) over millions of years would have been impossible. Most
of the bananas that you have eaten in your lifetime come from
immortal clones produced on plantations. Even in organisms
like mammals, which have germ-lines that separate very early
from the rest of the body, the survival and replication of the
cells responsible for producing gametes (germ cells) have pro-
ceeded for hundreds of millions of years. Life can continue
But even if life can propagate itself indefinitely, are there any
organisms that are free of aging, living with biological immor-
tality? I must be clear about one point concerning death: It
is not true that aging is required to kill organisms kept in the
laboratory. Showing that a species dies in the lab is not the
same thing as showing that immortality does not occur in that
species. Mechanical accidents in the lab will kill many soft-
bodied plants, animals, and microscopic creatures. Deadly
mutations can kill at any age or time. It is also impossible
to keep living things free of all diseases indefinitely. Being
free of aging does not imply the complete absence of death.
Biological immortals will often die, just not because of a sys-
tematic, endogenous, ineluctable process of self-destruction.
Death is not aging. Biological immortality is not freedom
Instead, the demonstration of immortality requires the find-
ing that rates of survival and reproduction do not show aging.
There are many cases where such patterns are inferred anec-
dotally among plants and simple animals, like sea anemones.
But the best quantitative data known to me were gathered
by Martinez , who studied mortality rates in Hydra, the