What Exactly Defines An “Egg?”

Eggs are the reproductive body produced by most multicellular organisms. Its evolution is still considered somewhat of a scientific mystery. The earliest single-celled organism would have reproduced using binary fission, where the organism split itself into two. However, as evolution progressed, multicellular organisms had developed a specialized group of cells that was capable of cumulation with another organism, leading to the formation of the very first “egg”. It would have resembled soft-bodied eggs, such as the ones laid by modern fish.

Live Birth v/s Laying Eggs

Today, most animals are categorized into one of two …