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What came first, the chicken or the egg?

  1. Jul 31, 2012 #1
    I think it is the chicken. I can't understand why there is such confusion?

    Why is it compared to the promblem over the first genetic material formed?

    Is there any explanation on the basis evolution or mutation that supports the egg to be formed first?
    Last edited by a moderator: Jul 31, 2012
  2. jcsd
  3. Jul 31, 2012 #2
    Re: Chicken vs Egg

    In the context of evolutionary biology, the standard answer is "egg", reasoning that if you trace the lineage of any chicken far enough back, you'll eventually end up with an ancestor that can't any longer be called a chicken - but the things it lays are nevertheless still eggs.
  4. Jul 31, 2012 #3
    Re: Chicken vs Egg

    Wait...how can you have a chicken without an egg?...how can you have an egg without a chicken?...no chicken, no egg...no egg, no chicken...but one had to come first...chicken...egg...chicken...egg... BWAK BWAK BUKAWWW!!!! *head explodes*

    (Lol, sorry I know I'm nutty. I agree with onomatomaniac)
  5. Jul 31, 2012 #4


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    Re: Chicken vs Egg

    Wrong! it's neither the chicken nor the egg.

    Publication The evolution of early animal embryos: conservation or divergence?
    From the author:
    Dilemma resolved..
  6. Jul 31, 2012 #5
    It's a bit of a flawed question; categories like "chicken" are taxonomic conventions created for our convenience. There is no instant at which a "chickens" appeared where there were none before; we just look at the categories that exist today and decide that a group of animals are similar enough (in features and in ancestry) to be placed within a single category.
  7. Jul 31, 2012 #6
    Which were we humans eating first, the chicken or the eggs?
  8. Jul 31, 2012 #7
    "The chicken (Gallus gallus domesticus) is a domesticated fowl", whereas eggs can be gathered from, inter alia, the nests of wild birds. Unlike domestication, gathering is as old as the human species. So the answer would again seem to be "egg".
  9. Aug 1, 2012 #8
    Re: Chicken vs Egg

    Don't you mean ovamatermaniac?
    The first chicken egg was laid by an animal that you wouldn't call a chicken. There was a an embryonic chicken in the egg, but the mother is considered a different type of bird.
    I am not sure that you are quite serious, but I will expand on this anyway. It may be useful to quote this post when similar issues come up.
    You made an error in logic. The "paradox" is based on a false hypothesis. The hypothesis is that a female animal has to lay an egg which is the same species as the mother. Obviously, if a dog could lay a chicken egg there would be no problem. However, we need not get so far. The line of discrimination between species can be somewhat arbitrary. A bird that is not a chicken, but very similar to a chicken, can lay an egg that hatches into a chicken.
    Let me ask an analogous question. Which came first, the king or the prince?
    A prince is the child of a king. However, the king had to grow up from a prince. So obviously, the theory of royal succession doesn't work.
    At some point, there were no kings or princes. Far back, somebody was charismatic and aggressive enough to get everyone to declare not only him as boss, but all his children and his children's children. So he had himself declared as king. He did not grow up as a prince.
    An example would be King Saul in the Bible. He was the first king. There was no prince and no king in Israel before him. So the king came first, in this example. In fact, the one that followed him was not a Prince. King David was not a prince. He replaced Saul as King.
    In fact, that happened quite often in history. So the king always came first, not the prince.
    Last edited: Aug 1, 2012
  10. Aug 1, 2012 #9
    Re: Chicken vs Egg

    Yes, I've just been thinking along similar lines, partly in reference to this thread. I'd say it quickly becomes more an issue of semantics than anything else, if one takes this far enough. Let's try a thought experiment inspired by the basilisk legend:

    "A [chicken/snake] lays [an avian/a reptilian] egg, from which hatches a [chicken/snake]."

    ("Avian" and "reptilian" is meant to refer only to the appearance and architecture of the egg.)

    Consider each of the eight sentences which can be formed by selecting one word from each of the pairs, and decide whether you'd call the egg in question a "chicken egg" under those conditions.
  11. Aug 1, 2012 #10
    Re: Chicken vs Egg

    How about archaeopteryx:


    wouldn't that work? That's a (proposed) transition species between dinosaurs (which laid eggs) and birds and I assume archaeopteryx is also laying eggs and then by continued evolutionary change, its lineage includes a branch which gradually (or sometimes abruptly) evolved into the chicken lineage. So from that perspective one could argue the egg came before the chicken, i.e., archaeopteryx was laying eggs long before the chicken emerged. However, not quite sure the question is referring to just eggs or bonifide chicken eggs.
    Last edited: Aug 1, 2012
  12. Aug 1, 2012 #11
    Re: Chicken vs Egg

    It doesn't really matter. In both cases, the egg came first. So long as the species is defined in the adult form, the egg came first. Since the morphology of embryos doesn't evolve as fast as the morphology of the adult form, scientists will continue to define a species in terms of the adult form.
    I assume that the species called chicken is defined in terms of the anatomy of the adult. The anatomy of embryos in the tail bud stage vary across class lines. However, I assume that the tail bud stage is conservative within any class of vertebrates. If so, one has to wait until the chick grows up to decide whether it is a chicken. By then, the egg has hatched.
    If he meant any eggs whatsoever, then clearly the egg came before the chicken. Purported eggs presumably from some invertebrate have been found in rocks 700 million years old. Thus, "eggs in general" preceded the vertebrates.
    If he meant the eggs of a "proper chicken", there is the question of how that egg is defined. When I look in any dictionary, the "chicken species" is defined in terms of its adult form. Thus, one would have to wait until the egg hatched before one decided that it was a chicken. Thus, the egg came first.
    If the evolution of the embryo wasn't conservative, then we would have a harder time. However, the greatest taxonomic detail occurs in the adult stage. Know one can tell what the species is from a blastula.
    Yes, I know that Haekel was wrong. Embryos even in the tail bud stage vary with taxon. You can tell the embryo of a fish from the embryo of a chicken in the tail bud stage. Haekel fudged his illustrations. However, I seriously doubt that you can tell the embryo of a chicken from the embryo of a duck at any embryonic stage. I suspect that it would be difficult to tell a newly hatched chicken from a newly hatched duck. Therefore, one has to wait for the corresponding chicks to grow up.
    The "proper chicken egg" had to proceed the "proper adult chicken". However, I wonder about those rare cases where the embryo evolution is not so conservative.
    It may be especially hard in the those animals that can reproduce both sexually and asexually. For instance, coral can reproduce by budding or by releasing eggs. Which came first, the coral adult or the coral egg?
    Then there are the organisms that form embryo-like stages by fusing individuals. Such as fungi. Such as slime molds.
    Which came first? The amoebic stage slime mold (asexual reproduction of protozoa-like cells), the slug stage slime mold (fusion of amoeboid individuals), or the spore (asexual reproduction of the multicellular slug)?
    Please take into account that a typical slime mold species has five independent genders!
  13. Aug 1, 2012 #12
    I read a theory that humans first started raising chickens for cock fighting. I think it was in a recent issue of Smithsonian Magazine. The popularity of chickens as a food came about only within the last four centuries, according to this article.
  14. Aug 1, 2012 #13
    Re: Chicken vs Egg

    "...evolution wasn't conservative...", What do you mean by that? Is it similar to the examples of fungi and coral you have given?
  15. Aug 2, 2012 #14


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    Re: Chicken vs Egg

    It would be good not to confuse people with this. Parents of 1 species don't give birth to offspring of different species. Organisms bequeath organisms so similar we consider them the "same species". Its important to remember here also that species in this context are arbitrary boundaries put upon the gradations of successive generations, for the ease of human convenience. Not natures.

    There is also another very, very important point to make here that may confuse readers reading your post. Its that evolution happens to populations. There is no "first chicken" or "first person" or "first of any species". Evolution is the change in allele frequencies over time for a population. It is incorrect, both conceptually and in reality, to think of a not-quite chicken giving birth to a chicken. At no point did such a finite line exist where a species "pops up". What did happen is a population of organisms reproduced and their alleles over time were sufficiently altered for us to label them as a distinct species. That is an easily misunderstood point--even often by students of the biological sciences. Think about it like a color bar;

    Its like asking where yellow becomes green. There is no finite point in the transition, only "populations of pixels" (think vertical lines) with changing RGB values (think of alleles). The "point" at which we consider 1 a "new" species in this case is going to be an artifact of human preference.

    For chickens and the rest of real life, this distinction between "species" in context becomes even harder to detect. A domestic rooster;


    A representative of that ancestral population, the red jungle fowl;


    A population of, according to us, almost chickens---but not quite chickens.

    I agree with the rest of your post though. I like the royal analogy--Just remember though that evolution is populations!
    Last edited by a moderator: Apr 19, 2017
  16. Aug 2, 2012 #15
    Regardless of the changes in allele frequencies in populations over time, it's scientifically undisputed that birds evolved from reptiles and reptiles laid (and continue to lay) eggs. So, with respect to chickens (which are birds), the egg came before the chicken.

    EDIT: My question is why mammals had to develop a new way. The avian egg is relatively simple and quite elegant IMO. The mammalian way is too complicated, messy and unnecessarily hard on the mother. Has a chicken ever died from the complications of pregnancy?
    Last edited: Aug 2, 2012
  17. Aug 2, 2012 #16


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    Having live young has its advantages. Ever seen a lowly raccoon raid a giant alligator nest, destroying all the young? Having your babies with you circumvents that problem.
  18. Aug 2, 2012 #17
    Well I've never seen a lowly raccoon raid a giant alligator nest, so I have to either take your word for it or demand a peer reviewed reference. Seriously, there are certain advantages to gestation and live birth, but our avian friends are doing just fine. They can fly south for winter without having to take a plane or get hotel reservations. And they can hang around the pool without feeling self-conscious because they're obviously pregnant. Besides we are talking about avian eggs, not reptile eggs. The birds perfected the egg IMO. They usually guard their eggs 24/7 until they hatch. I don't have a ready reference for it, but I've read that with many bird species, the female forms a monogamous relationship with the male to share egg minding duties. If you insist, I will find a reference for this. But you will then need to find a reference for the lowly raccoons (and not non-lowly raccoons) and giant alligator nests (it's not clear to me whether you mean giant alligators or giant nests, so you will need to cover both).
    Last edited: Aug 2, 2012
  19. Aug 2, 2012 #18
    Re: Chicken vs Egg

    I meant that there is a stage in the development of the embryo where evolution doesn't seem to move as fast as in other parts of the embryo.
    Part of the development of the embryo is considered the phylotypic stage. The phylotypic stage is where the general anatomy of the embryo is characteristic of every species in that particular phylum. Sometime this idea that there is a phylotypic stage that slowly evolves is called the hour-glass model.
    In chordates, the stage at the beginning of the tailbud is considered phylotypic. Recent studies have pointed out that the tailbud stage isn't identical in every class of chordate. Yes, you can distinguish the tailbud embryos of fish, birds and mammals. The number of pharyngeal slits vary quite a bit, as does the size of the yolk sac. However, the adult stages of development vary even greater than the tailbud stage. An adult fish is very easy to distinguish from an adult bird.
    The trochophore stage of the development of mollusks is also considered a phylotypic stage. Adult mollusks are very different from each other. The adult stage of bivalves, gastropods and chitons are very different. However, the earliest larval stage of each class is the trochophore. Trochophores don't vary much. Some cephalopods don't have a trochophore stage. However, the resemblance of trochophores to each other despite class is rather amazing.
    The hourglass model explains this resemblance by hypothesizing that the phylotypic stage evolves very slowly compared to the other stages in development. Evolution works slower in the phylotypic stage than on the adult stage. The reason is that the tailbud stage of the embryo is basically protected from harm. The adult has to make a living. The ova and sperm have to compete. However, the phylotypic stage is generally the most passive stage in the animals existence. The tailbud embryo just has to grow in the chordate mother. The trochophore stage of a mollusk is plankton, and just floats.
    The hour-glass model has taken a beating in recent years. Haekel was a rather single minded scientist of the eighteenth century that pushed the hour-glass model to an extreme. Haekel may have even misrepresented some of his data. He claimed that the early embryo was identical within a phylum of animals. This is very wrong. However, the general structure of the phylotypic stage is similar within a phylum. The proportions of each phylotypic feature may vary greatly from class to class, but the same anatomical features are present in all classes for the animal in the phylotypic stage.
    I was pointing out that the egg obviously came first since the general structure of the birds egg is the same from bird to bird. The colors on the eggs may differ, but a birds egg is a birds egg. The adult bird is something else. Adult chickens vary in appearance from other birds, and even from each other. Therefore, the egg of the first chicken was indistinguishable from the eggs of other birds. It wasn't until the first chicken grew up that anyone can say, "This is a weird type of bird. I will call it a chicken." Therefore, the egg had to come first.
    The other examples that I gave were organisms that don't have a clear phylotypic stage. Even their individuality is questionable. Some don't even need eggs to reproduce. They occasionally lay eggs anyway, but don't critically need the egg in any one generation. Therefore, the question of "what came first" is considerably more complicated in their case. Which did come first, the coral adult or the coral egg?
    Last edited: Aug 2, 2012
  20. Aug 2, 2012 #19
    One can carry ones eggs with you. Some amphibians do that.
  21. Aug 2, 2012 #20
    I will bet that there were penguins that did.

    Viviparity can be useful both in cold climates and in aquatic environments.

    Egg laying is a real problem in cold climates. The egg can freeze solid without some means of keeping it warm. Perhaps the first placental mammals, or even the first marsupials, lived in very cold climates.
    It is even possible that the cold weather during the KT extinction killed off most egg-laying mammals.

    Viviparous lizards live tend to live in cold climates. It is thought that they evolved this to avoid getting frozen. Here is a link to an article about viviparity in squamate reptiles.
    “Cold climates and the evolution of viviparity
    in reptiles: cold incubation temperatures
    produce poor-quality offspring in the lizard,
    Sceloporus virgatus
    Evolutionary origins of viviparity among the squamate reptiles are strongly associated with cold climates, and cold environmental temperatures are thought to be an important selective force behind the transition from egg-laying to live-bearing. In particular, the low nest temperatures associated with cold climate habitats are thought to be detrimental to the developing embryos or hatchlings of oviparous squamates, providing a selective advantage for the retention of developing eggs in utero, where the mother can provide warmer incubation temperatures for her eggs (by actively thermoregulating) than they would experience in a nest.”

    One bird that has a real problem with eggs freezing solid is the penguin. Emperor penguins have this very elaborate migrating behavior, practiced by both parents, that has evolved to keep the egg from freezing. This is a very risky behavior. The males stand a good chance of starving to death while incubating the eggs.
    Here is an article on emperor penguins. Yes, they lay eggs. However, that is an accident of history. I conjecture that emperor penguins wish they were viviparous. Here is a free link on the hard life of emperor penguins.
    “The Emperor Penguin is perhaps best known for the sequence of journeys adults make each year in order to mate and to feed their offspring. The only penguin species that breeds during the Antarctic winter, it treks 50–120 km (31–75 mi) over the ice to breeding colonies which may include thousands of individuals. The female lays a single egg, which is incubated by the male while the female returns to the sea to feed; parents subsequently take turns foraging at sea and caring for their chick in the colony. The lifespan is typically 20 years in the wild, although observations suggest that some individuals may live to 50 years of age.”

    Air breathing tetrapods that return to the sea have to do something about their eggs. If the eggs are laid in water, the embryo could drown. Maybe that is why many marine snakes are viviparous. Here is a link (buy on line) on viviparous sea snakes.
    The viviparous sea snakes (Hydrophiinae) comprise ∼90% of living marine reptiles and display many physical and behavioral adaptations for breathing, diving, and achieving osmotic balance in marine habitats.”
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