The question regarding which came first, the chicken or the egg, has been a puzzling mystery for many. Considering the continuous cycle, it may be quite a futile matter to delve into. However, it is also a matter that could be important for evolutionary biologists.
Nevertheless, science has something to say regarding this puzzling matter.
Chicken or Egg Puzzle
According to Live Science, several biologists claim that eggs preceded chickens. Basically speaking, eggs are simply the sex cells of females. Amniotic eggs, which are hard eggs that can be externally laid onto the ground, served as remarkable game changers among vertebrates.
Paleontologist Koen Stein from the Royal Belgian Institute of Natural Sciences says that eggs are vital when it comes to the evolution of vertebrates. This is because eggs enable amniotes to go further from water.
Live Science reports that before these hard eggs dawned, vertebrates depended on the presence of water for their reproduction. This is a limitation that several amphibians still face, given how their eggs need to be kept moist for survival.
According to a study published in the Current Biology journal, true birds were not reflected in the fossil records before. It was only during the middle to late Jurassic period, roughly 150 to 165 million years ago, that they showed up.
However, according to the Biodiversity Center of the University of Texas, the first eggs with shells may have evolved way before such a period. This means that the egg indeed preceded the chicken.
Earth's First Eggs
Live Science reports that the first eggs had a leather texture and were probably malleable. They could be largely similar to eggs laid by platypuses and reptiles of the present.
Several vertebrates that dwelled on land laid amniotic eggs during the Triassic, Permian, and Carboniferous times. Among the many animals of these periods, the most famous ones were dinosaurs. Stein looked into some eggshells of dinosaurs, which are among the earliest known ones. These remnants date to the early Jurassic era, roughly 200 million years ago.
The thickness of the shells was only a hundred microns, which is roughly equivalent to the thickness of a human hair strand. However, considering the structure, such dinosaur eggs could have been rigid and not flexible, which means that they could be the earliest discovered example of the common hard-shelled eggs of today.
Such thinness could be the reason why specialists found it hard to spot prehistoric eggshells. Live Science notes that, when eggs get into contact with acidic and rich soil, they start dissolving slowly. Stein expresses that it is impossible for such thin shells to be preserved because of the soil.
Because of the soft-shelled nature, the exterior did not fossilize well, Nature.
Did Eggs Really Come Before Chicken?
While this may seem to close the case, things change when actual chickens enter the picture. Live Science reports that chickens are likely to have evolved from the red jungle fowl subspecies. These birds then got domesticated over time, according to a PNAS study.
As they got domesticated, the huge ancestor of present-day chickens would have laid an egg that was genetically distinct from its parent. Such a chicken embryo would have grown within the distinct egg before it hatched.
When the species reached adulthood, it would then proceed to lay the earth's first chicken egg. Considering this, the chicken may have preceded the egg.
However, such a history is not quite straightforward. Due to a vast history of interbreeding and domestication, it is quite hard to pinpoint the actual original chicken.
Nevertheless, this goes to show that the answer to the puzzle is not linear and depends on various considerations. However, what scientists agree on is that both chicken and eggs are delicious to eat.
RELATED ARTICLE : Eating Fried Chicken Everyday Could Lead to Early Death, Study Says
Check out more news and information on Animals in Science Times.
