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Name: James
Status: Other
Age: 30s
Location: N/A
Country: N/A
Date: 2002


Question:
What contains more information, a chicken or an egg ? This is a semi-serious question that I have been thinking about for years. It concerns the nature of information (or data)



Replies:
Are you asking about the gross amount of information or the type of information? A chicken has more cells, each cell having the same amount of DNA (except the sex cells of the chicken). As far as the egg goes, it depends on whether it has been fertilized or not. If it has, it has the same amount of DNA per cell but has less cells than the chicken. So the type of info would be the same, but the gross amount would be less. If it has not been fertilized, it has half the amount of information as the chicken in each cell.

The part about what it "knows" is not really relevant, because each chicken knows slightly different things, but not necessarily different amounts of things. And also just because chickens are bigger does not necessarily mean it is "more highly" evolved. Some plants have more genes than mammals.

vanhoeck


You are correct that "the nature of information" is central to answering your question. From a genetic standpoint, the fertilized egg, by definition, contains essentially all of the genetic information coding for an adult chicken. There are some comparatively minor genetic alterations as the adult matures, such as normal gene rearrangements and some scattered mutations, but their genetic composition remains essentially unchanged during development.

As to the concept of evolution, new traits often arise simply through the normal recombination between parental chromosomes during fertilization. Spontaneous mutations can contribute to this process, as well. So new genetic information, regardless of its origin, must be inherited through reproduction to be perpetuated in a particular species. But it is not necessarily true that more "evolved" species contain more genetic information. It is now believed that humans do not contain a great deal more active genes than many much less "evolved" species. There is even evidence that some "lower" species actually contain more genetic material than species that are more "highly evolved". The amount of genetic material that an organism requires really depends more upon their needs for surviving in a particular environmental niche than upon their evolutionary status.

The most difficult aspect of your question is whether or not the knowledge and experience gained during maturation constitutes an actual increase in information by the chicken. It would seem logical that the mature adult chicken brain contains vastly more "information" than the newborn chick, and certainly more than in the unborn egg. But this is very different than genetic information.

The chicken itself could be duplicated using the genetic information alone. Its knowledge and experiences, its "consciousness", are a by-product of its genetics and its environment, which cannot be directly inherited or duplicated. Thus, one might argue that this "learned" information is of even greater significance than the basic blueprints provided by the chicken's genes. So, I would say that the adult chicken does contain far more "information" than the egg.

It seems similar to comparing a brand new computer with that same computer after the operating system and software have been installed. I think it is pretty clear that the "fully loaded" version would contain much more "information". Although none of these programs would be required to build a duplicate of the computer itself, the new computer would not be the "same" until it was loaded with the same software, as anyone whose experienced a hard drive crash knows well. The biggest difference is that the computer cannot replicate its basic components itself, but the manufacturing process takes care of that.

Anyway, thank you for the most interesting question and I hope that this has given you some more to think about,

Jeff Buzby, Ph.D.


This depends on what you call "information". If you are referring to genetic information stored in the DNA there is no doubt that an adult vertebrate organism holds more genetic information than a fertilized egg. There are numerous post fertilization modifications to the genome of a developing organism that are not passed on to the offspring. Two that occur quite often are viral insertions in somatic cells and T-cell memory of antigenic exposure with concomitant "memory cells".

Peter Faletra Ph.D.
Assistant Director
Science Education
Office of Science
Department of Energy


You have answered your own question about chickens and eggs. One comment I will add is that a chicken's body will also contain information - torn feathers, full belly, whatever - reflecting its history, in addition to what knowledge it has in its little bird brain.

As for evolution, it is not necessarily in the direction of increasing information. All that evolution really requires is change over time. Organisms can become simpler or more complex as the occasions arise. As heritable mutations in organisms' genomes arise, those that increase the organism's "reproductive fitness" are preserved, while those that decrease it are not. What constitutes reproductive fitness can vary as environmental conditions, population densities, competition, etc. changes.

What makes a chicken "more evolved" than a fly? Is it because a chicken is bigger than a fly? Both flies and chickens have had the same amount of time to evolve to their present state. The ancestors of chickens and flies split off from their common ancestor a long time ago, but both have continued to evolve since then.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois


An interesting question! You are right in noting that the crux of the matter is the nature of information, or how you define the word information.

But first, we need to know if there is a rooster in the henhouse. An egg has one half the "normal" amount of DNA, since the other half will come from the sperm when the egg is fertilized. So if you are comparing an unfertilized egg to a chicken, the chicken wins hands down. But if the egg has been fertilized, then we have to consider a tie vote. Both the fertilized egg and the chicken contain the same amount of DNA, so as far as the information content of the organism, they are equal.

If you bring in what the chicken "knows," then we start mixing apples and oranges, in my opinion. We are using information in two very different ways:

1) the information content of DNA, which encodes the entire structure of the chicken, and
2) the "knowledge" of the chicken, which is based upon the interactions among the neurons in the chicken's brain. Some of those neuronal connections are fixed at birth, but other connections are more "plastic," meaning they are formed as a response to stimuli, etc. -- in other words, what we consider "learning." Of course, the ability of the brain to form connections came from, where else, the DNA. If you are willing to lump in learned information with encoded information, then I guess the chicken wins, but I am not totally comfortable with that umbrella term for information.

I do take minor issue with one statement you made, the a chicken is more evolved than a fly. The problem arises from the casual way that we throw the word "evolved" around. Generally when you say chickens are more evolved than flies, what you are really saying is that chickens arose later in the process of evolution than the organisms which gave rise to our current insects. But, and this is key, both organisms have undergone continual evolution up to today. In other words, let's say that X million years ago, a series of random mutations accumulated (over hundreds of thousands of years) that allowed reptiles to have feather-like scales, then stronger muscles, etc., etc., until we have what looks like a bird. You might say that birds are more evolved than reptiles, in the sense that you are using the phrase above. But, in the same X million years that birds have evolved, reptiles have also continued to evolve. In the strict sense then, I would say that reptiles, birds, and insects are all highly evolved, and that one has not evolved more than the other since the original split. But all of this is just semantics. Thank you for an interesting question!

Paul Mahoney, PhD



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