Life, 518 Million Years Ago
An extraordinary fossil deposit discovered in the Chinese site of Qingjiang allows us to observe, as in a photograph, the wide variety of life forms that populated the shallow waters of a Cambrian sea
For over three billion years, life on Earth existed only in the form of single-celled organisms. Then, around 600 million years ago, unequivocal fossil traces, found in many parts of the world, testify to a vast and sudden spreading of multicellular life during the Precambrian. It is the Ediacaran biota. Very strange-looking life forms spread in the shallow coastal seabed, originating a bizarre fauna, which paleontologists consider
a kind of global experiment in multicellular life, driven by natural selection to find the most suitable body shapes and structures for survival.
Within a few million years, and for reasons we do not know, the Ediacaran biota became extinct, giving way to life forms a little less bizarre, more similar to those that still populate the planet today. The earliest and best-known evidence of this new flourishing of multicellular life, which took place in the middle Cambrian, just over 500 million years ago, is found in the thousands of fossil specimens discovered and cataloged since 1909 by…
