WEBVTT - What Came First, the Chicken or the Egg?

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<v Speaker 1>Welcome to brain Stuff, a production of iHeartRadio, Hey brain

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<v Speaker 1>Stuff Lauren vogelbamb here. The age old question of what

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<v Speaker 1>came first, the chicken or the egg has confounded many

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<v Speaker 1>and inspired plenty of hopefully friendly debates. Here's the dilemma.

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<v Speaker 1>A chickens come from eggs, but you need a chicken

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<v Speaker 1>to lay an egg. But can we figure out the

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<v Speaker 1>answer to this question once and for all. Let's look

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<v Speaker 1>at the evidence for both sides of the argument. Eggs

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<v Speaker 1>have existed in nature for more than a billion years,

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<v Speaker 1>long before of any chicken was on the scene. Technically,

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<v Speaker 1>an egg is just a container bound by membranes that

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<v Speaker 1>allows an embryo to grow and develop with nutrients and

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<v Speaker 1>at least a little protection from the harsh outside world.

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<v Speaker 1>Almost all sexually reproducing species make eggs. An egg is

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<v Speaker 1>just another word for the specialized cells that are female

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<v Speaker 1>sex cells. Now. Animals originally laid their relatively simple eggs

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<v Speaker 1>in ponds and other water borne environments, because otherwise the

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<v Speaker 1>eggs would have dried out at some point. Though maybe

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<v Speaker 1>around three hundred and twelve million years ago, give or take,

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<v Speaker 1>amniotic eggs came on the scene. These were eggs with

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<v Speaker 1>three extra membranes inside. These membranes created a complex system

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<v Speaker 1>within the egg to support the developing animal. A nutrient system,

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<v Speaker 1>a waste system, a wave of exchanging air with the

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<v Speaker 1>outside world aka respirating, and a bonus, a shell that

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<v Speaker 1>would protect the egg even it did get dry on

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<v Speaker 1>the outside. This allowed for land based reproduction and paved

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<v Speaker 1>the way for today's birds and reptiles and mammals too,

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<v Speaker 1>though we tend to develop those life support structures in

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<v Speaker 1>an internal placenta instead of an external egg. But okay,

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<v Speaker 1>let's talk chickens. In nature, living things evolved through changes

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<v Speaker 1>in their DNA. In an animal like a chicken, a

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<v Speaker 1>DNA from a male sperm cell and a female egg

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<v Speaker 1>meet combined to form a zygoat, which is the first

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<v Speaker 1>single cell of a new baby chicken. This first cell

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<v Speaker 1>divides innumerable times to form all of the specialized cells

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<v Speaker 1>of the complete animal. Although those cells do all kinds

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<v Speaker 1>of different work in the animal's body, they usually all

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<v Speaker 1>contain exactly the same DNA, the DNA that was created

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<v Speaker 1>when the zygoat was created. So, in the case of chickens,

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<v Speaker 1>a fertilized egg laid by a hen should hatch into

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<v Speaker 1>a baby chick and either a butting hen or rooster

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<v Speaker 1>will be revealed. Once the chickens hatch, the process starts

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<v Speaker 1>all over again. They grow, produce sex cells, and might

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<v Speaker 1>well reproduce to create more fertilized eggs. Fun side note,

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<v Speaker 1>female chickens will produce in lay eggs whether they get

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<v Speaker 1>fertilized or not, kind of similar to how female humans

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<v Speaker 1>usually produce eggs and then ject them through mensturation, whether

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<v Speaker 1>they get fertilized or not. So yes, the chicken eggs

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<v Speaker 1>that we eat are just large unfertilized female sect cells

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<v Speaker 1>which happened to be delicious when poached or scrambled. But okay,

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<v Speaker 1>we were talking about what came first. Eggs predated chickens

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<v Speaker 1>by a long shot, but these were not chicken eggs.

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<v Speaker 1>The very first chicken would have been a genetic mutation

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<v Speaker 1>from two other birds that we might call proto chickens.

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<v Speaker 1>The domestication process that led to this event happened over

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<v Speaker 1>a long period of evolutionary history, during which the genetic

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<v Speaker 1>makeup of all of these non chickens was edited through

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<v Speaker 1>small changes caused by the mixing of the parent's DNA

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<v Speaker 1>or mutations to that DNA that produced each new zygoat.

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<v Speaker 1>So what eventually happened was that two non chickens mated

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<v Speaker 1>and the DNA in their new zygoat contained the combinations

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<v Speaker 1>and or mutations that produced the first chicken that was

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<v Speaker 1>more or less like the ones we know and love today.

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<v Speaker 1>Scientists believe that the parents of the first chickens were

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<v Speaker 1>red jungle fowl, which are native to Southeast Asia. At

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<v Speaker 1>some point long in the past, people there got to

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<v Speaker 1>work domesticating red jungle fowl, that is, breeding them specifically

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<v Speaker 1>for desirable traits such as less aggression and in this case,

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<v Speaker 1>more prolific egg production. The road toward chicken, and thus

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<v Speaker 1>toward chickens crossing roads, seems to have been a complex one.

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<v Speaker 1>Archaeological evidence has suggested that the first true chicken appeared

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<v Speaker 1>around ten thousand years ago. However, DNA analysis and a

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<v Speaker 1>bit of advanced probability mathematics has suggested that the chicken

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<v Speaker 1>diverged from the red jungle fowl much farther back, around

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<v Speaker 1>fifty eight thousand years ago, and also that some of

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<v Speaker 1>the modern chickens jeans, like the ones that sometimes create

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<v Speaker 1>the yellow color on the skin of their legs come

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<v Speaker 1>from interbreeding with other types of jungle fowl. After that,

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<v Speaker 1>at any rate, if a chicken developed from a red

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<v Speaker 1>jungle fowl egg, then you could argue that the chicken

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<v Speaker 1>came first, and afterward it grew up to produce the

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<v Speaker 1>first chicken egg. But consider it this, Before that first

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<v Speaker 1>true chicken zygoat, there were only non chicken jungle foul species.

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<v Speaker 1>The zygoat's cell is where DNA combinations and mutations take

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<v Speaker 1>place to produce the blueprint for a new animal. The

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<v Speaker 1>zygoat cell then grows its own egg. So therefore, the

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<v Speaker 1>first true chicken egg must have come before the first

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<v Speaker 1>fully realized chicken queed. Today's episode is based on the

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<v Speaker 1>article what came first, the Chicken or the Egg? On

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<v Speaker 1>HowStuffWorks dot Com written by Leah hoy. The Brainstuff is

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<v Speaker 1>production of iHeartRadio in partnership with how stuffworks dot Com,

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<v Speaker 1>and it is produced by Tyler klang A. Four more

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