Neil deGrasse Tyson has settled it once and for all .....Which came first the Chicken or the Egg?

[Playinghardball]

Neil deGrasse Tyson @neiltyson · Aug 20
Just to settle it once and for all: Which came first the Chicken or the Egg? The Egg -- laid by a bird that was not a Chicken

[valerief]

1. Love it! Evolution!!!!! nt

[Scootaloo]

2. A better answer is, "how do you define 'chicken'?"

[Xipe Totec]

9. Order Galliformes

http://en.wikipedia.org/wiki/Galliformes

Family: Phasianidae

Genus: Gallus

[Scootaloo]

15. see Jimlup's post downthread

These taxonomic designators are actually wholly arbitrary - oh, they're fine for current use. But when we go backwards or forwards in evolution they start to fall apart.

Sticking with the chicken... if we follow a chicken's maternal ancestry ALL the way back, from one hen to the next, we're going to notice something - at no point in that chain of organisms, is the individual we're looking at particularly different from its immediate ancestor or immediate progeny.

That is, there is no cutoff point where "not-chicken' stops, and "chicken" begins. We will never find a point where the progeny is a chicken, but the parent isn't. We can leapfrog several generations in either direction and probably find a "not-chicken" on the maternal line, but again, we will find no discernible point where that whatever-it-is organism "stops' and the next in line "begins."

This is part of the reason creationists go on about "micro-evolution' as if it disproves speciation - they can't wrap their heads around ht notion that there is no clear speciation "cutoff point" - Every organism born is going to resemble its parents vastly more than it will be different from them. And so will it offspring, and so on down the line. so it's easy enough to look around the modern day, see a crocodile and a duck and say "they're totally different' - it's a little different when you go back to the middle of the Triassic and find out that crocodiles and ducks share a common archosaur ancestor - one that happens to not be a crocodile or a duck (and is itself not very distinguished from its ancestors or descendants...)

[Xipe Totec]

18. Chicken in Spanish is Gallina; Gallinacea, Gallus. Get it? nt

[BrotherIvan]

29. whoah

that was a mind-bender.

[Scootaloo]

31. Yeah, biology is amazingly fun like that!

It's a good thought exercise fro realizing the interconnectedness of stuff.

i reccomend Dawkins' "The Ancestor's Tale" if you want a hefty, informative read about the subject

[BrotherIvan]

37. I haven't read much on biology in a while

And I'm woefully behind on physics. I think about it and love any show about wildlife. The universe trips me out regularly.

[rickyhall]

41. I'm wondering about the story I read the other day

about the two ant species in one ant hill. One specie came from the other but can't produce progeny with the other would be sorta like what Tyson's saying.

[Scootaloo]

42. And (and communal insects in general) are... weird

basically every ant in a colony is the same organism - the result of an eternally-cloned fertilized egg from a single queen. it might be more accurate to regard individual ants as organs of the colony rather than individual creatures, because really, that's how an ant colony works.

In the case of the ant colony you describe - this one? - my guess would be at some point the original queen's egg-replication went a little faulty - maybe due to being exposed to toxins, a virus, or some other mutagen - and resulted in an "improper copy" - which led to a mutant strain of (apparently fertile) ants that the rest of the colony would still recognize as "one of us' rather than "invasive intruders." The species has since continued its own parasitic evolutionary course.

[hedda_foil]

24. Wow! That thar is one purdy rooster.

[WillyT]

3. K & R !!!

[muriel_volestrangler]

4. Yeah, didn't we work out that answer before we were ten?

It's sort of basic to understanding of evolution - "fish lay eggs too, chickens evolved from fish (via other creatires)".

[progressoid]

22. Blasphemer!!

I didn't work it out until I was 14.

[KittyWampus]

5. Only a chicken can lay a chicken egg, though.

Some performers can "lay eggs".

[Igel]

26. That's precisely wrong.

If you define "chicken" closely enough to be able to say, "This is a chicken, while these few genetic differences make this fowl a non-chicken," you're pushing the limits of sanity. But at the same time, you get to answer the question.

I'm not going to use the phrase "chicken egg" because in daily life it can mean "egg laid by a chicken" or "an egg that produces a chicken" (at least if fertilized). There's a 100% overlap between the two, so there's no need to distinguish. In this case, that distinction is crucial.

Genetic mutations happen in eggs, in sperm, and during the genetic recombination that is fertilization. Those changes can happen in a hypothetical not-quite-a-chicken so that the fertlized egg that results is a chicken. A non-chicken lays an egg that produces a chicken. Where there was no chicken there is an egg that will produce a chicken. No chicken can still lay an egg that will produce a chicken.

Once fertilized, that embryo's genetics are set. That egg, if its genetics say "chicken," will either fail to develop or will produce a chicken. If the genetics say "not quite a chicken," you get no chicken. No egg = no chicken.

The egg came first.

Of course, Tyson is far from the first to point this out. He's just the first person that some will notice pointing it out, and people assume that if they don't have information it doesn't exist. They didn't have information that somebody else came up with this argument, so that information can't exist.

[grahamhgreen]

52. Sounds like Omlettulate Conception...

[Chathamization]

53. That doesn't seem right.

The egg exists before fertilization so you'd have to either assume that all the mutations needed to make it a chicken occurred in the egg or that the act of fertilization turned the egg from a red junglefowl egg into a chicken egg (though it'd seem like the act of fertilization is about when you'd start separating the chicken from the egg). Someone could argue that the answer is a chicken, hatched from a red junglefowl egg, and it's probably a better answer.

Of course, as others have pointed out the real answer is that this is arguing nomenclature where no firm line of separation exists.

[Tree-Hugger]

6. K&R nt

[Yavin4]

7. That's gross. n/t

[chollybocker]

8. This also answers another important question:

Q: Why did the chicken cross the road?

A: Because it was not chicken.

[rhett o rick]

11. What's the definition of "cross"?

[jimlup]

10. Eh, kinda but not strictly correct...

If we define a "chicken" as an animal that could successfully breed with a chicken then the parent could almost certainly have breed with a "chicken".

Species are defined as separate if they can not interbreed with each other. This process takes many generations so eventually, over many generations, the direct ancestors of chickens would not be able to breed with "chickens".

Sorry to be a stickler here. Actually, I would have expected deGrasse-Tyson to know this. Maybe 'cause he's an astronomer and never had a biology teacher as a colleague (I'm a physics teacher) I'll forgive him.

There is no exact dividing line, which is the point of the parable.

[BlueJazz]

12. I'll ask Superchicken when I see him.

Cluck Kent

[rhett o rick]

13. Looks to me like you are backing up his theory. If a chicken evolved from something

other than a chicken, and that other thing laid eggs, that would mean that there were eggs existing long before chickens existed. As you are a physics teacher, I will give you some leeway.

[jimlup]

16. Fair enough

Yeah, when I first read it I didn't think about it that way. But you're right...

[MattBaggins]

17. No he is correct

We have defining characteristics that are used to categorize the birds in the genus gallus. If we were to go back in time watching the evolution of chickens, at some point there would have been a bird with none of the characteristics of a chicken, that laid an egg with the genetic mutation, that gave rise to an offspring that was a rudimentary chicken.

[Scootaloo]

19. No, actually...

at no point would we be able to draw a line saying "On this side are individuals that are chickens, and on this side are individuals that are not chickens." At every juncture in the chicken's ancestry, every offspring would have been the same sort of creature as its parents, and of its own offspring.

Now we can find creatures that are ancestral to chickens that are themselves not chickens. But we would be unable to define the exact point that the "change" happened, unless the condition of chicken-hood is based entirely on a single particular feature that arose from a single particular mutation - and while I'm no expert on chicken biology, I don't think they're one of the handful of species that work like that.

And the really weird thing is?

These primeval almost-chickens... probably looked more like a chicken, than a lot of modern chickens do!

[MattBaggins]

23. No actually

We would reach a point where the parent could no longer be classified as a chicken

At some point back in time the chickens ancestors were fish.

[Scootaloo]

25. I think you misunderstand

we would of course reach ancestors that are clearly not chickens - whether they be fish or archosaurs or some sort of pheasant / grouse / whatever living in North Vietnam in the Pliocene. We could definitely tell the difference between a chicken, and the fish at theroot of its (our) family tree.

But where would we draw the line between the modern chicken, and its most recent ancestor? How could we actually do so? we could certainly understand that one is one and the other is the other... but... we wouldn't actually be able to demonstrate this, even if we had every single individual involved in the process at hand.

There really is no solid point where "most recent ancestor" ends and "chicken" begins. Nor for that matter is there a point where "ancestor before that" ends, and "most recent ancestor" begins.

It's an unbroken continuum, all the way back to whatever amino soup was frothing around on earth's frosty shores way back before the Paleozoic

This is actually an important issue with tracking human evolution - we've got this awkward divide of "archaic homo sapiens" and "modern-type homo sapiens" for example - both of which could contain different species, or which all might be the same species with simple ethnic or individual variation.. .and this is without figuring contemporaneous human species we're finding in the area as well! Because what we're finding isn't actually a species-by-species catalogue of ancient human remains, but more of a... genetic cloud of multiple populations and individuals all swamping together over a period of about a million years. So yeah, we can tell the difference between a type-specimin "Homo erectus" and a human skeleton from last week.. .but... there's a gloudy gradient between the two that gets murkier and murkier the closer to th middle you get.

This is just the way it is for every species on earth. we define species by how differnet htye are from other species, but when you go back, the differences shed away as you draw close to common ancestors, so how do you keep the "species" designation? At what point does one species stop and new one begin?

Richard Dawkins has pointed out that gaps in the fossil record are pretty much the only thing that keeps Paleontologists and taxonomists from going completely fucking bonkers. Can you imagine if we actually DID have access to every individual ancestor of modern rabbits (or chickens?) all the way back to the Paleozoic? They would be impossible to classify!

[tclambert]

48. So you're saying there could be several generations of "almost chicken" between chicken

and "not a chicken," yes? The "almost chickens" could breed with either and could be classified as either, and don't seem quite different enough to warrant their own species designation. So line-drawing may not be so clear.

Am I capturing the essence of the argument there?

Then there are donkey-horse crosses (mules), zebra-horse crosses (zorses) and zebra-donkey crosses (zedonks). Very strange since the primary species involved have different numbers of chromosomes. Horses have 64; donkeys have 63; and zebras have 32 to 46, depending on species or subspecies of zebra.

And now I'm wondering if, given the right anti-rejection drugs and an embryo implantation procedure, could a chicken could lay a duck egg?

[DocMac]

49. I would like to thank you

for taking to time to type that. I'm impressed.

[mathematic]

20. That's not the definition of chicken or species

Both terms are defined by scientific consensus. Many people involved in the consensus use the reproduction rule. However, this rule is clearly inadequate as there are many examples of different species successfully producing fertile offspring.

Additionally, the chicken-or-egg problem predates the theory of evolution by two millennia, dating back to Aristotle (who liked to write about the causes of things). Back then it was more related to a "what created the Creator?" type of problem.

[tclambert]

46. The Creator must have created him/her/itself. Which implies the Creator is a time traveler.

He jumps in His TARDIS and pops back to the beginning of time and creates Himself. Every schoolchild on Gallifrey knows that.

[Igel]

30. At the same time, there are numerous species that can interbreed.

And produce fertile offspring.

It's serious problem in cactus taxonomy, for instance, where you get continua of species across the Sonoran desert. At this end, you get one set of genes, flower morphology, spination, etc., etc. At some point in the middle, you get a different set, sufficient that they can't interbred. At the far end of the continuum, you get something that can't interbreed with either the midpoint or the first end point.

That makes it sound like there's just a line. But it's in 2D, with the same problem along any line you draw through the sometimes discontinuous territory.

Yet at every point along the way, there's a lot of interbreeding and gene flow. Even at recent discontinuities there's gene flow.

Taxonomy's a bear because where you define the type for the first species essentially dictates the number of species you come up with in the end and what they look like. Start in the middle, you get one number. Start in the southern extreme, you might get a second. Start in the NW corner, you get a third set of species.

Rules of historical precedence come into play, cladistic analysis, and the old fallback of having a type set by a good, solid description and analysis for the individuals in a well defined given locality.

(I teach HS physics, but was a cactus fancier married into a family of desert botanical garden curator-professors. Currently wondering how my small Ariocarpus and Rebutia collections will fair in Houston's unpredictable winters.)

[Scootaloo]

33. So are the cacti ring species like california salamanders or arctic gulls?

or are they more of a murky genetic soup like wolf / coyote / dog populations?

[Jackpine Radical]

39. That's actually an antiquated definition of species.

Wikipedia:

Some biologists may view species as statistical phenomena, as opposed to the traditional idea, with a species seen as a class of organisms. In that case, a species is defined as a separately evolving lineage that forms a single gene pool. Although properties such as DNA-sequences and morphology are used to help separate closely related lineages,[6] this definition has fuzzy boundaries.[7] However, the exact definition of the term "species" is still controversial, particularly in prokaryotes,[8] and this is called the species problem.[9] Biologists have proposed a range of more precise definitions, but the definition used is a pragmatic choice that depends on the particularities of the species of concern.[9]

[tclambert]

47. Horses, donkeys, mules. Each has a different number of chromosomes.

Male donkey (62 chromosomes) + female horse (64 chromosomes) ==> mule (63 chromosomes). On rare occasions, female mules have given birth, sometimes to mules, sometimes to full horses.

Horses and donkeys are regarded as different species. But what species are mules? Are they horse, donkey, or their own separate species?

[rhett o rick]

14. Ask the same question to a Zen Master and he might say,

"Can you hear the sound of one chicken clapping in the woods, if no one is around?"

[Maedhros]

21. Ontogeny recapitulates phylogeny.

The egg came first.

[Aerows]

27. Yep

That's what I learned in Biology.

I had a professor and that was her favorite saying to describe the evolutionary process.

She was a freaking brilliant woman.

[Martin Eden]

28. I drew that conclusion a long time ago

Seemed obvious, and I have a small fraction of Tyson's intellect.

[Capt. Obvious]

32. Egg = breakfast; chicken = dinner

Pretty self evident.

[Scootaloo]

34. As a chef, i'm apalled

You've never had chicken quesadillas for breakfast? never had a quiche for dinner?

where's my fainting couch?

[Capt. Obvious]

35. Hey, I'm Portuguese

We put eggs on top of every dinner

[Scootaloo]

36. Well, good! Eggs are the best part of the chicken!

Well, that and the skin. Mmmm, crispy crispy creamy-backed fried chicken skin

[a2liberal]

38. exactly

both my brother and I have always (without discussing a priori) agreed that this is the obvious answer

[Purrfessor]

40. If life begins at conception, why did God feel...

it necessary to create Adam and Eve as fully-functioning humans?

[Man from Pickens]

43. I came to that conclusion 20 years ago

someone shower me with intellectual praise please

[underpants]

45. Welcome to DU

I hope you find it everything you want

DU Wise and Otherwise.

[underpants]

44. Been saying that for years

Thanks Neil

[Jamastiene]

50. I always thought it was the rooster.

Well, it does make sense, in a way, if you really think about it.

[qazplm]

51. I would tweak it

An egg laid by a bird that was almost a chicken.