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The following article is taken from John Clayton’s Dandy Designs, a collection of articles from the bi-monthly bulletin, Does God Exist?, July, 1979. I think you will find it fascinating.


One of the evidences for the existence of God that we have repeatedly presented in this publication is the evidence from science that there is design in the creation. If one can prove there is design in the creation, one knows there has to be a Designer because design cannot occur in living or in non-living things by chance. We believe this Designer is God and that if an intelligent, thinking person will examine the evidence available, they will see it is impossible for these things to occur by any other process than God’s intelligence and direction. The Bible repeatedly makes reference to these things, telling us in Romans 1:19-23, for example, that we can know there is a God through the things He has made. We are all familiar with passages such as the one in Psalms which tell us the heavens declare the glory of God and the firmament showeth His handiwork. There are numerous claims throughout the Bible maintaining that God’s design is able to be seen in His creation.

One of the more beautiful examples of design in living things is in the structure of the bird egg. You may think in looking at an egg that it is really not that remarkable a structure, but repeated studies done by scientists in various areas and with various features of experimental design have shown that, in fact, the egg is a really incredible structure. Readers may wish to investigate Scientific American (February, 1979 or March, 1970) to see more material along this line. The article in Scientific American in March of 1970 on how an egg shell is made is particularly interesting.

The interesting thing about a bird egg is that it is a self-contained life support system. All the nutrients, minerals, energy sources, and water that will be needed by the embryo during its incubation are already present in a freshly laid egg. But there is one thing that the egg does not have and this is oxygen. Somehow, the egg has to be able to provide oxygen to the organism inside and yet get rid of the waste products that are involved. How do you do this through an apparently impenetrable egg shell? We have to realize that the eggs of birds and other organisms such as spiders and reptiles do not show any respiratory movements. There are no air currents within the egg, and there are no capillaries involved. Instead, the egg must breathe by a process chemically known as diffusion.

Diffusion is the process by which gases move from areas of high concentration to low concentration. In the area of an egg shell, diffusion is through thousands of microscopic pores in the shell of the egg. The lower concentrations of oxygen inside the egg allow oxygen to diffuse through the shell from outside. The high concentration of carbon dioxide inside the egg shell allows the gases to move out to spread into the atmosphere outside where the carbon dioxide is of a lower concentration. One has to realize there is virtually no carbon dioxide in our atmosphere, but about 21% oxygen. Apparently, God has not only designed the bird egg to be able to make these exchanges, but has designed the atmosphere with the capability of exchanging as well.

An interesting experiment which has been done along these lines is to attach an egg to a source of air and put it under water. By injecting pressurized air into the egg shell at the blunt end of a chicken egg, bubbles are seen to emerge from the entire surface of the shell. This experiment was first done by John Davy of Edinburg in 1863, but has been recently reproduced and circulated in numerous photographs by Dennis Atkinson of State University of New York at Buffalo. We have actually discovered that the chicken egg has about 10,000 microscopic pores distributed all over its surface which exchange the gases with its atmosphere.

It is also interesting to notice that the water content of the air within the egg is greater than the water content of the air outside the egg. This means that the pores not only allow oxygen to diffuse through the pores, but also allow water molecules to diffuse out. Bird eggs are designed to lose water at a controlled rate. Most of the energy needed for embryonic development is taken from the fat material stored inside the yolk. For every gram of fat burned, there is also equal mass of water generated. This means that the relative water content of the egg during incubation will decrease. If the relative water content at hatching were to be measured and compared to the water content when the egg was laid, it would be found that about 15% of the original mass of the egg was lost. Those who raise chickens are aware that the longer an egg sits, the more water loss there is. This is the amount of water loss that is essential for successful hatching, and scientists have even learned to determine whether an egg is progressing satisfactorily or not by whether or not it is losing the right amount of water.

During the 21 days that it takes a chicken egg to hatch, an egg which weighs about 60 grams will take up about 6 liters of oxygen, give off 4½ liters of carbon dioxide and 11 liters of water vapor.

The shell of a chicken egg is made of a material similar to limestone. The material is calcium carbonate which forms columnar calcite crystal. These crystals are imperfect, having a small amount of organic material within them. The imperfect packing of these crystals leaves spaces that allow the material to be transported through the egg. The permeability or conductance of the shell to gases is delicately controlled to meet the embryonic needs inside the egg. If gas is conducted too rapidly through the shell, the egg will dehydrate and if gas conductance is too low, the baby chick inside will suffocate.

A happy medium must be struck between the rates at which the gases are conducted through the shell. The way this is done is that as metabolism takes place and gas enters the shell to replace the lost water, an air cell is formed at the blunt end of the egg. The air cell grows until it occupies about 15% of the internal volume of the egg. This occurs at the end of the incubation period. The oxygen consumption of the embryo increases slowly during the first week and a half of life; between 10-14 days it reaches a plateau which it maintains up until hatching. This plateau of 6 milliliters of oxygen per day is the volume that the pores of the cell are able to pass by diffusion. This means that the rate of oxygen movement is exactly equal to what the shell is able to diffuse. In different terms, what this means is that every second about 20 trillion oxygen atoms flow into the egg through each cell and 14 trillion molecules of carbon dioxide and 12 trillion molecules of water vapor flow out.

All of this intricately designed system provides for the chick up until about the 19th day. On or about the 19th day, the chick penetrates the air cell at the blunt end of the egg with its beak. This process is called “internal pipping.” The chick then begins to breathe from this air cell ventilating its previously unused lungs. During this period, oxygen is provided by both diffusion and convection. About six hours after the chick has penetrated the air cell in the eggs, it pokes a hole in the shell. This small hole produced by the egg tooth on the upper beak of the chick provides atmospheric oxygen for the first time. By this time the lung function is well enough established to allow increased oxygen consumption which is required during the final effort of hatching.

The engineering principles involved in this process are even more remarkable when one considers different kinds of eggs. Not all eggs have the same size pores, but all eggs end up producing the same final concentrations of oxygen and carbon dioxide within the egg. It is rather remarkable when one considers that the incubation of bird eggs ranges all the way from 11 days in some small birds to 70 days for large birds such as the Wandering Albatross. The chemistry involved in a system such as this of moving gases and providing for the embryo inside the egg seems virtually impossible to explain in terms of any kind of evolutionary process. It is another example of God’s wisdom and design in the creation–a design that demands a Designer.


Cora Gail Trent
www.cgtrent.com
cgtrent@att.net