1.
As to the question,
which came first,
the Chicken or the Egg?
the egg has existed on Earth
for at least several hundred million years,
while the Hen has been here
only fifty million years.
And the difference between them,
is the difference between mortality
and immortality. (a)
An egg does not die a natural death.
The egg's single cell continually divides,
and grows into a multi-celled organism.
For most animals, however,
the process of death and dying
is inevitable.
We know that sexual reproduction –
the mixing of two different sets of chromosomes –
leads to programmed cell death in an offspring,
and ultimately to the demise of the adult.
As microbiologist extraordinaire
Lynn Margulis likes to remind us:
death is a sexually transmitted disease.
One consequence of programmed cell death is population control.
If it were not for the inevitability of death,
the population of a species could easily inflate to a critical size,
leading to an increased competition for resources,
and under extreme circumstances,
to the elimination of the entire species.
Barring a random accident,
the Egg
will continue to persist
without the threat of death or dying.
While the Chicken, on the other hand,
must ultimately sacrifice itself
for the survival of the species
as a whole.
2.
In direct contrast, it is possible
that proteins may have evolved
prior to DNA molecules. (b)
Proteins are the structural building blocks of an organism,
while DNA is typically located inside the nucleus.
If you think of the nucleus as the embryo or egg,
and proteins as its protecting membrane,
or material body,
then one may conclude
that the chicken, did in fact, come before the egg.
(a) Guy Murchie, The Seven Mysteries of Life
(b) Amy Robinson, in conversation
The Chicken and the Egg 