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Speaker 1: Welcome to brain Stuff, a production of iHeartRadio, Hey brain

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Speaker 1: Stuff Lauren vogelbamb here. The age old question of what

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Speaker 1: came first, the chicken or the egg has confounded many

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Speaker 1: and inspired plenty of hopefully friendly debates. Here's the dilemma.

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Speaker 1: A chickens come from eggs, but you need a chicken

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Speaker 1: to lay an egg. But can we figure out the

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Speaker 1: answer to this question once and for all. Let's look

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Speaker 1: at the evidence for both sides of the argument. Eggs

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Speaker 1: have existed in nature for more than a billion years,

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Speaker 1: long before of any chicken was on the scene. Technically,

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Speaker 1: an egg is just a container bound by membranes that

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Speaker 1: allows an embryo to grow and develop with nutrients and

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Speaker 1: at least a little protection from the harsh outside world.

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Speaker 1: Almost all sexually reproducing species make eggs. An egg is

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Speaker 1: just another word for the specialized cells that are female

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Speaker 1: sex cells. Now. Animals originally laid their relatively simple eggs

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Speaker 1: in ponds and other water borne environments, because otherwise the

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Speaker 1: eggs would have dried out at some point. Though maybe

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Speaker 1: around three hundred and twelve million years ago, give or take,

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Speaker 1: amniotic eggs came on the scene. These were eggs with

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Speaker 1: three extra membranes inside. These membranes created a complex system

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Speaker 1: within the egg to support the developing animal. A nutrient system,

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Speaker 1: a waste system, a wave of exchanging air with the

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Speaker 1: outside world aka respirating, and a bonus, a shell that

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Speaker 1: would protect the egg even it did get dry on

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Speaker 1: the outside. This allowed for land based reproduction and paved

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Speaker 1: the way for today's birds and reptiles and mammals too,

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Speaker 1: though we tend to develop those life support structures in

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Speaker 1: an internal placenta instead of an external egg. But okay,

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

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Speaker 1: in their DNA. In an animal like a chicken, a

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Speaker 1: DNA from a male sperm cell and a female egg

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Speaker 1: meet combined to form a zygoat, which is the first

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Speaker 1: single cell of a new baby chicken. This first cell

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Speaker 1: divides innumerable times to form all of the specialized cells

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Speaker 1: of the complete animal. Although those cells do all kinds

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Speaker 1: of different work in the animal's body, they usually all

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Speaker 1: contain exactly the same DNA, the DNA that was created

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Speaker 1: when the zygoat was created. So, in the case of chickens,

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Speaker 1: a fertilized egg laid by a hen should hatch into

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Speaker 1: a baby chick and either a butting hen or rooster

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Speaker 1: will be revealed. Once the chickens hatch, the process starts

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Speaker 1: all over again. They grow, produce sex cells, and might

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Speaker 1: well reproduce to create more fertilized eggs. Fun side note,

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Speaker 1: female chickens will produce in lay eggs whether they get

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Speaker 1: fertilized or not, kind of similar to how female humans

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Speaker 1: usually produce eggs and then ject them through mensturation, whether

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Speaker 1: they get fertilized or not. So yes, the chicken eggs

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Speaker 1: that we eat are just large unfertilized female sect cells

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Speaker 1: which happened to be delicious when poached or scrambled. But okay,

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Speaker 1: we were talking about what came first. Eggs predated chickens

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Speaker 1: by a long shot, but these were not chicken eggs.

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Speaker 1: The very first chicken would have been a genetic mutation

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Speaker 1: from two other birds that we might call proto chickens.

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Speaker 1: The domestication process that led to this event happened over

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Speaker 1: a long period of evolutionary history, during which the genetic

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Speaker 1: makeup of all of these non chickens was edited through

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Speaker 1: small changes caused by the mixing of the parent's DNA

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Speaker 1: or mutations to that DNA that produced each new zygoat.

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Speaker 1: So what eventually happened was that two non chickens mated

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Speaker 1: and the DNA in their new zygoat contained the combinations

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Speaker 1: and or mutations that produced the first chicken that was

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Speaker 1: more or less like the ones we know and love today.

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Speaker 1: Scientists believe that the parents of the first chickens were

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Speaker 1: red jungle fowl, which are native to Southeast Asia. At

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Speaker 1: some point long in the past, people there got to

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Speaker 1: work domesticating red jungle fowl, that is, breeding them specifically

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Speaker 1: for desirable traits such as less aggression and in this case,

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Speaker 1: more prolific egg production. The road toward chicken, and thus

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Speaker 1: toward chickens crossing roads, seems to have been a complex one.

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Speaker 1: Archaeological evidence has suggested that the first true chicken appeared

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Speaker 1: around ten thousand years ago. However, DNA analysis and a

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Speaker 1: bit of advanced probability mathematics has suggested that the chicken

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Speaker 1: diverged from the red jungle fowl much farther back, around

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Speaker 1: fifty eight thousand years ago, and also that some of

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Speaker 1: the modern chickens jeans, like the ones that sometimes create

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Speaker 1: the yellow color on the skin of their legs come

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Speaker 1: from interbreeding with other types of jungle fowl. After that,

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Speaker 1: at any rate, if a chicken developed from a red

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Speaker 1: jungle fowl egg, then you could argue that the chicken

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Speaker 1: came first, and afterward it grew up to produce the

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Speaker 1: first chicken egg. But consider it this, Before that first

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Speaker 1: true chicken zygoat, there were only non chicken jungle foul species.

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Speaker 1: The zygoat's cell is where DNA combinations and mutations take

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Speaker 1: place to produce the blueprint for a new animal. The

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Speaker 1: zygoat cell then grows its own egg. So therefore, the

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Speaker 1: first true chicken egg must have come before the first

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Speaker 1: fully realized chicken queed. Today's episode is based on the

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Speaker 1: article what came first, the Chicken or the Egg? On

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Speaker 1: HowStuffWorks dot Com written by Leah hoy. The Brainstuff is

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Speaker 1: production of iHeartRadio in partnership with how stuffworks dot Com,

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Speaker 1: and it is produced by Tyler klang A. Four more

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Speaker 1: podcasts from my heart Radio visit the iHeartRadio app, Apple Podcasts,

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