The albumen (egg white)
and yolk of the egg serve as food for the growing embryo during
the incubation period.
Yellow yolk is
White yolk is produced at night
and contains more protein.
What provides the place where
the embryo develops?
The
blastoderm is an early stage of the embryo, present when
the egg is laid.
What grows during the incubation
period to ultimately become the chick?
What surrounds and protects
the yolk?
What functions to suspend the
egg yolk in the center of the egg?
The chalazae allow the yolk
to rotate and they function to keep the blastoderm on the top side of
the yolk, close to the heat of the hen's body.
The egg white or
albumen consists of several layers that surround and protect the blastoderm
and yolk .
What contains a large amount
of water which is needed by the developing embryo?
Gases (for example oxygen and
carbon dioxide) can pass through the shell because it is gas-permeable.
If the shell were not gas-permeable,
the embryo would die
Water vapor can also pass through
the shell, but the shell does act to slow the loss of water, so that enough
is retained inside the egg for the growing embryo.
One of the functions of the
shell membrane is to provide a barrier to disease organisms (for example
bacteria).
The air space normally develops
As
the egg incubates the air space increases in size to compensate for carbon
dioxide and water loss.
