all beings and all desires rose up toward it.
Therefore at its rise and at its every return,
shouts and hurrahs and all beings and all
desires rise up toward it.
— Chandogya Upanishad, ca. 800 BCE
What makes an egg an egg? Of the two
reproductive cells, it’s the larger, less mobile
one. It receives the sperm cell, accommodates
the joining of the two gene sets, and then
divides and differentiates into the embryonic
organism. It also provides food for at least the
initial stages of this growth. This is why eggs
are so nutritious: Like milk and like plant
seeds, they are actually designed to be foods,
to support new creatures until they are able to
fend for themselves.
Improving the Package The first animal eggs
were released into the equable oceans, where
their outer membrane could be simple and
their food supply minimal. Some 300 million
years ago, the earliest fully landdwelling