# The Chicken and the Egg **URL:** \ **Category:** Factual Questions\ **Created:** [June 9, 2008, 9:13am UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310 "2008-06-09T09:13:02Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [June 9, 2008, 9:13am UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/1 "2008-06-09T09:13:02Z")
While eating a hard-boiled egg, I started to think about its nutritional value. For instance, the amount of calcium in the yolk and white. There must be enough calcium and other materials to create the skeleton of a baby chick. The more I thought about it, the more I wondered how the contents of an egg get transformed into a baby chick. It’s a closed system, unlike the uterus of a mammal. It seems like the contents of the egg are transformed into a baby chick with great efficiency. How does this happen, and where do the waste products go? ---
**Author:** ![Amblydoper](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@Amblydoper](https://boards.straightdope.com/u/Amblydoper)\ **Post date:** [June 9, 2008, 9:46am UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/2 "2008-06-09T09:46:40Z")
[From here](http://www.answersingenesis.org/creation/v24/i3/egg.asp) “…With the embryo closed off from the outside world by the shell,2 there is the problem of how to dispose of excretory wastes. Here is where the allantois is so crucial, as it serves as the embryo’s garbage bag. (When the chick hatches, the accumulated wastes can be found sticking to the inside of the abandoned shell.)” ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [June 9, 2008, 10:13am UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/3 "2008-06-09T10:13:12Z")
I was expecting something new about the “What came first?” debate when I read the thread title, but I was disappointed. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [June 9, 2008, 10:18am UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/4 "2008-06-09T10:18:59Z")
[QUOTE=Schnitte] I was expecting something new about the “What came first?” debate when I read the thread title, but I was disappointed. [/QUOTE] The egg. ---
**Author:** ![Myself](https://avatars.discourse-cdn.com/v4/letter/m/8491ac/32.png) [@Myself](https://boards.straightdope.com/u/Myself)\ **Post date:** [June 9, 2008, 8:38pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/5 "2008-06-09T20:38:52Z")
The chicken. ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [June 9, 2008, 8:45pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/6 "2008-06-09T20:45:02Z")
[QUOTE=Myself] The chicken. [/QUOTE] Yes, but only after the egg. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [June 9, 2008, 9:17pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/7 "2008-06-09T21:17:36Z")
[QUOTE=Schnitte] Yes, but only after the egg. [/QUOTE] Yes, but only after the chicken. ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [June 9, 2008, 9:29pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/8 "2008-06-09T21:29:59Z")
[The BBC set up a high-profile expert panel, and they agreed on the egg.](http://news.bbc.co.uk/2/hi/uk_news/england/nottinghamshire/5019682.stm) ---
**Author:** ![Autolycus](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@Autolycus](https://boards.straightdope.com/u/Autolycus)\ **Post date:** [June 9, 2008, 9:39pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/9 "2008-06-09T21:39:55Z")
[QUOTE=panache45] Yes, but only after the chicken. [/QUOTE] Yes, but only after the egg. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [June 9, 2008, 9:45pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/10 "2008-06-09T21:45:20Z")
The chicken came first, according to the site cited by **CoG888**. Answers in Genesis? Was that the most reliable site you could come up with? ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [June 9, 2008, 10:02pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/11 "2008-06-09T22:02:47Z")
Well, last time I saw the cartoon, it was the egg contentedly smoking a cigarette, and the chicken looking disgruntled (or disclucked) and say “Well, I guess we settled _that_ question”. ---
**Author:** ![Chimera](https://avatars.discourse-cdn.com/v4/letter/c/8e8cbc/32.png) [@Chimera](https://boards.straightdope.com/u/Chimera)\ **Post date:** [June 9, 2008, 10:51pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/12 "2008-06-09T22:51:28Z")
That’s why an egg is such good food. It has to contain all the necessary ingredients - nutrients and elements - to create a fully functional miniature chicken (or other species, as applicable). It doesn’t really contain much waste, because the chick isn’t digesting raw materials with the expectation of absorbing the needed material and excreting the rest. ---
**Author:** ![Amblydoper](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@Amblydoper](https://boards.straightdope.com/u/Amblydoper)\ **Post date:** [June 10, 2008, 5:11am UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/13 "2008-06-10T05:11:03Z")
I can’t come up with a “more reliable” site, sorry. All the references in the article are either dead ends or broken links. I don’t have access to the book that their facts likely came from (Curtis, H., Biology, 4th Ed., Worth Publishers, New York, pp. 859-864, 1983), and my google-scholar-fu isn’t good enough. I am not headed to the library anytime soon either. So, I retract my previous answer about waste products in the egg. However, while searching for a better source, I found the answer to another of the OP’s questions… “… _The final stage, the making of the shell, occurs in the uterus, or shell gland, and takes about 14 hours. The shell is about 4% protein and 95% calcium carbonate, materials which again are secreted by the surrounding tissue. Much of the Calcium needed is removed from the honeycomb-like structure of the hen’s own bones. The principle function of the shell, of course, is mechanical protection, though the embryo does derive some calcium from it. Since the enclosed embryo is alive and, although it can not breathe, needs a constant supply of air, the shell is porous and allows oxygen to pass in, carbon dioxide to pass out_…” Harold McGee, “On Food and Cooking: the Science and Lore of the Kitchen.” Fireside, New York, 1984, page 61. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [June 10, 2008, 4:13pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/14 "2008-06-10T16:13:14Z")
[QUOTE=CoG888] I can’t come up with a “more reliable” site, sorry. All the references in the article are either dead ends or broken links. I don’t have access to the book that their facts likely came from (Curtis, H., Biology, 4th Ed., Worth Publishers, New York, pp. 859-864, 1983), and my google-scholar-fu isn’t good enough. I am not headed to the library anytime soon either. So, I retract my previous answer about waste products in the egg. [/QUOTE] I should have added a smiley. Your cite was accurate enough for the most part; the stuff about evolution, not so much. Here’s a more complete (and more reliable 😉 ) cite: [http://chickscope.beckman.uiuc.edu/explore/embryology/day04/4Focuson\_1.html](http://chickscope.beckman.uiuc.edu/explore/embryology/day04/4Focuson_1.html) > [@](#): > > **The Chorio-Allantoic Membrane** > > Ectoderm and somatic mesoderm form the chorion which lines the eggshell and performs gas exchange and waste elimination. The allantois is the embryo’s connection to the chorion. It appears as a balloon-like structure coming off the hindgut at about day 4 or 5. It is made up of endoderm and splanchnic mesoderm and carries with it the allantoic vessels coming off the heart. The allantois grows larger as the chick grows, wraps around above the chick, and fuses with the chorion. **It works together with the chorion to exchange gasses between the embryo and the outside environment. The egg shell is porous and thus allows oxygen and carbon dioxide to pass freely back and forth from the environment to the inside of the egg. The chorio-allantoic membrane is also responsible for drawing calcium from the egg shell and carrying it back to the chick.** Calcium is needed to carry on general metabolism and make bone. For the first ten days the chick can absorb a sufficient amount of calcium from the yolk. But at around day 10, the formation of bones begins to accelerate and the embryo must draw calcium from the egg shell. **The allantois also stores wastes (urine) once the embryonic kidneys begin to function.** When the chick hatches, the chorio- allantoic membrane remains attached to the egg shell and is therefore discarded with it. ---
**Author:** ![Myself](https://avatars.discourse-cdn.com/v4/letter/m/8491ac/32.png) [@Myself](https://boards.straightdope.com/u/Myself)\ **Post date:** [June 10, 2008, 7:26pm UTC](https://boards.straightdope.com/t/the-chicken-and-the-egg/452310/15 "2008-06-10T19:26:16Z")
Or the reptile. The creature with the machinery to lay an egg had to come before the first egg was laid. QED!