Which Came First, the Chicken or the Egg?
If chickens must hatch out of chicken eggs, how could there ever be a first chicken?
The egg. This question is less “philosophical” than you might think…
This classic scientific conundrum has been used in a few ways, down the long years since Charles Darwin caused all that trouble with his “monkey book”.
Among those who dispute the reality of evolution, it’s used to illustrate the problem of the “first cause”. If every animal is descended from an earlier animal… how did the whole thing start? That’s abiogenesis, and it doesn’t just break the rules of how our biosphere works right now, it breaks our definition of life itself.
Life is tricky to define. For now, we describe life as a selfsustaining, selfcontained grouping of one or more cells, which were generated by other, earlier cells. From the merest bacteria to the blue whale, all life has cells, of one kind or another.
Also crucial to the definition is this idea that all cells have ancestor cells, and they go on to create new cells themselves. Most of the time, cells just divide into (almost) perfect copies, either to repair damage or to increase the total number of cells in – ie grow the organism of which they are part. But every now and then, two very special cells come together to create a new, separate, selfcontained organism that can go off into the environment and, in the case of the chicken, murder pennylizards.
This is of course the essence of sexual reproduction. Cells combine genetic material to create novel new forms, to beat those fiendish cellhijacking viruses and all the other nasties that exploit the way our cells work.
Repeat this process of reproduction billions of times over millions of years, and various copying errors, random changes, even the occasional cosmic ray, cause the organisms to change and, well, evolve.
The problem of course is in identifying when a creature stops being a dinosaur and starts being a bird. Evolutionary scientists
know there isn’t a
specific day when Species 1 ends and Species 2 takes over. No hairy Homo
erectus suddenly gave birth to a weirdly bald and intelligent Homo sapiens. It happens over time. Extremely long periods of time.
Critics of evolution like to use the example of the chicken and the egg though, because that extra step – birds are “born” on one day, then “hatch” on a different day – adds extra confusion. If a proto- chicken lays an egg that hatches into a chicken… was that a proto- chicken egg, or was it a chicken egg?
If they’re being particularly belligerent, these critics will point out that the internal machinery required to build an egg is very complex, so how could a thing-that-wasn’t-a- chicken possibly include the right machinery inside it to make a chicken egg?
And this is where the evolutionists step in and try – again – to explain that the bird we call a “chicken” didn’t just suddenly pop out of a dinosaur egg or something. It has a bird ancestor which already laid eggs. And before that, eggs were used by dinosaurs of course, and even earlier, by amphibians too.
So obviously, “the egg” as a tool for helping baby chickens develop to a size large enough so they can survive when they finally hatch, came first.
But ah, say the critics. We’re not asking if the chicken’s ancestors laid eggs. We’re asking how an animal that needs to develop in an egg could ever come out of an animal that wasn’t the same species.
One day, a bird we now recognise as a chicken, had to be born. There had to be a “first chicken”. But if chickens can only hatch out of chicken eggs, how did this happen? How could a, let’s call it a neander chicken, lay a chicken egg?
To answer this, it’s helpful to realise there’s no such thing as a chicken.
Oh fine, semantically of course there are chickens. My mother has some. But in a biological sense, this idea of organising animals into discrete species and saying “that animal there is a grizzly bear, and that one there is a red kangaroo” is very human, and nature doesn’t really pay that much attention to it.
What each of us are, in an evolutionary sense, is the organism that has been constructed by a set of genes. Our genes provide the fundamental instructions for what we look like (though our environment affects the fine details, of course).
If you look only at genes over time, it’s not exactly straightforward to tell where one species gives way to another. A million generations of a horse-like creature might show a slow loss of one particular set of genes, while a mutation elsewhere slowly becomes dominant and gives the horselike creature, say, hooves.
There’s no point in time where a horse with no hooves popped out a foal and said “Look at this freak’s feet!” If you had a time machine and made multiple stops, say every few hundred thousand years, you’d need to photograph thousands of horse-feet and then arrange them chronologically. Only then would you see a very slow and gradual change from soft toes to a single, hardened hoof.
It’s a bit like growing up. You never really think of yourself as being bigger than you were 20 years ago. But the photographic evidence is clear. You used to be really small. But the growth happened so slowly, it only struck you every now and then how big you were getting.
Now, this isn’t the same mechanism as evolution, but it gives a sense of how gradual the process is.
From ancestor bird to chicken, a long unbroken line of birds kept laying eggs, each chick was slightly different to its parents, and over millions of years these differences built up to a point where the bird now looked like what we call a chicken.
This is true of how animals involve, but in the specific case of the CHICKEN and the CHICKEN EGG, we didn’t need to get into evolution. Because it turns out the answer to this question is really easy, and doesn’t require any knowledge of evolutionary theory at all.
One day there was a bird that wasn’t a chicken, and it laid an egg, and that egg hatched into a chicken. How do we know? Because we were there and, very probably, we made it happen.
Specifically, humans in Asia no earlier
Think of the craziest rooster you ever fled from and multiply by about ten
than 7000 years ago, bred a red junglefowl with a grey junglefowl to produce the domestic bird we Aussies call a bloody idiot chook.
That’s right. Chickens are junglefowl like dogs are wolves (see box). Why don’t more people answer the question this way? Because they don't think in terms of species, maybe. If someone is trying to use a particular animal to challenge evolution, the first thing you should do is check what the animal has supposedly evolved from. The chicken is Gallus gallus domesticus, a subspecies of Gallus gallus, , the red junglefowl. Because of the chicken’s yellow skin gene, and a few other genetic markers, there’s strong evidence that the red junglefowl was hybridised with the grey junglefowl (Gallus sonneratii).sonneratii). sonneratii)
Why did this happen? Some studies suggest Asian cultures first bred red junglefowl for cock-fighting, around 5000 BCE. Further genetic analysis of chickens, though, shows that domestication took place in several areas and even as far west as India.
The red junglefowl was a good candidate for domestication because, among other things, it can massively boost its rate of reproduction when it has access to plenty of food. All we have to do is feed ‘em up, and the junglefowl produces lots of eggs. Yummy!
At some point, what probably started by accident became very much deliberate, and domesticated junglefowl – true chickens – were introduced to Europe around about 3000 BCE.
Those were pretty mad chickens though. Think of the most craziest, peckhappy rooster you ever fled from screaming as a child, and multiply by about ten. Getting chicken eggs, even as a Roman, would have been a bit of a test of fortitude. You'd need a stick.
Recent DNA analysis of chicken bones shows that in the Middle Ages, chicken breeders finally began selecting for birds that were less aggressive and which began laying earlier.
This is an important point actually. Even over the time we’ve had the chicken – only 7000 years, give or take – we’ve continued to change it. Just look at all the amazing breeds and varieties at the Royal Easter Show. Quite what the Romans would have thought of our hypotrophied breast-muscled, relatively bland-tasting frankenchickens created as a result of industrial farming, I shudder to think. So the next time someone busts out this tired old cliché of a scientific “gotcha”, you can now respond as we all should have for years. The egg came before the chicken, because the first chicken (well, the first clutch really) had a red junglefowl for a mother.
The large image is a chicken, and the smaller (right, inset) a grey junglefowl. The family resemblance is very clear.
Like dogs, chickens have the genetic ability to be bred into hundreds of different phenotypes.