DESIGN IN BIRD EGGS

The miraculous creation of birds does not end with wings, feathers or their migration skills. Another extraordinary design feature of these creatures is in their eggs.

However ordinary it may seem to us, the egg of a chicken has about fifteen thousand pores resembling dimples on a golf ball. The spongy structure of smaller eggs can only be observed under the microscope. These spongy structures give eggs added flexibility and increase their resistance to impact.

An egg is a miracle of packaging. It supplies all the nutrients and water that the developing foetus needs. The yolk of the egg stores protein, fats, vitamins and minerals, and the white works as a reservoir of fluid.

The developing chick needs to inhale oxygen and exhale carbon dioxide. It also requires a source of heat, calcium for its bone development, protection of its fluids, protection against bacteria and physical impact. The eggshell provides all of these for the chick, which breathes
through a membranous sac that develops in the embryo. Blood vessels in this sac bring oxygen to the embryo and take carbon dioxide away.

Eggshells are amazingly thin and sturdy, and so transmit the body heat of the brooding parent.

A Necessary Loss

Section of egg

During incubation, the egg loses 16% of its water content in the form of evaporation. Scientists long believed this to be harmful and due to the porous structure of the eggshell. However, the most recent research shows this loss to be necessary for the chick to emerge from the egg. The chick needs oxygen and space to be able to move its head just enough to crack the shell while hatching. The evaporation of water creates the room and oxygen required.

Chicks have a special "egg tooth" that they use only to hatch the egg. This tooth is formed just before hatching and, amazingly, disappears after hatching. The eggshell is strong enough to protect the embryo during twenty days of incubation. However, it is also easily breakable so that the chick can emerge.

Furthermore, water loss ratio is adjusted to vary between 15 to 20% for ideal conditions depending on the type of eggshell. For instance, water loss in the eggs of loons is a few times higher than in others that incubate under dryer conditions.

This article is based on the works of www.Harunyahya.com