Life's Great Mysteries - Which came first, the chicken or the egg?

Often touted as an impossible conundrum, this question is actually easier to answer than you might think. The answer is, quite clearly, the egg. We simply need to go back in time to examine things.

The first eggs with waterproof shells that could be laid on land appeared about 312 million years ago. Most biologists agree that domestic chickens came from a tropical bird that still exists today in the forests of Southeast Asia, called the red junglefowl (Gallus gallus). Humans began domesticating red junglefowls about 10,000 years ago, eventually creating a new bird subspecies (Gallus gallus domesticus… aka the chicken). As you know, humans eventually spread domestic chickens around the world.

So, in one respect, eggs obviously predated chickens by hundreds of millions of years. But this is an oversimplification of the question. Let’s consider the very first chicken—the very first individual that had the genetic characteristics that made it a new subspecies. Well, genetic variation comes about through a process called mutation. This is true whether we’re talking about life forms that live wild, or those that humans breed for certain desirable characteristics. The genetic variation comes from the same phenomenon—mutations. These mutations cause new physical traits, and these traits are selected, either by the forces of nature (natural selection) or by humans (artificial selection). Sometimes the mutations cause changes that are significant enough that the new individual is considered a new subspecies or even a new species (this usually occurs incrementally over time, but sometimes it can happen relatively quickly).

Anyway, long ago, there was a time when a male red junglefowl mated with a female red junglefowl, and a mutation occurred in the process of the male’s sperm cell fertilizing the female’s egg cell. The mutation resulted in the very first bird that could be considered a chicken (Gallus gallus domesticus). This fertilized egg formed a chicken egg, with the embryo developing inside the egg. The very first chicken hatched out of that egg. So… the first chicken egg came before the first chicken. Mystery solved, right?

But wait! If you think about it, that very first chicken came from an egg that developed inside a female red junglefowl. That means the egg was a red junglefowl egg. And the first chicken egg didn’t exist until that first chicken grew up and laid her own chicken egg. Which means the chicken came before the egg!

Now I’m just confused.

Photo Credits:
- Chicken and egg - DepositPhotos