In paleontology, the origin of vision has its source in an enigma that has been called the “Cambrian explosion”.
At the beginning of the Cambrian era, 543 million years ago, evolution had led to the creation of three major families of animal life. Barely 5 million years later, there were 38! Nowadays this number has hardly changed. Over a short period of time, a veritable explosion of life took place, a mystery still unsolved by scientists.For zoologist Andrew Parker, who developed the so-called “Light Switch” theory, it is the appearance of the sense of vision that would have allowed this explosion of life.
On the eve of the Cambrian explosion, the sense of vision was present at an embryonic stage: in certain creatures, we could distinguish organs with photosensitive cells capable of distinguishing darkness from light.
The first living being to have a real eye (that is to say, an ocular system capable of leading to the perception of an image, is the trilobite, a small arthropod that has now disappeared but whose appearance corresponds exactly to the start of the Cambrian explosion.
Thus, this new sense of vision would have given an evolutionary advantage so disproportionate that it would have led to a veritable "arms race" among all creatures, thus allowing this unprecedented acceleration of evolution.
This period of the Cambrian explosion was intensively studied by scientists including Charles Darwin, who saw in it an argument against his theory of natural selection. Indeed, according to Darwinian theory, evolution was enabled by small, gradual changes, stretched over very long periods of time. So he had trouble understanding this sudden acceleration of evolution!
Parker's Light Switch theory therefore aims to bridge the gap between Darwin and the scientific and historical fact of the Cambrian Explosion.
It was only after the appearance of the sense of vision that living beings, both plants and animals, added various colored elements to their adornment. The appearance of color is therefore intrinsically linked to that of the sense of vision.
Source: A. Martel "The Power of Light" Editions Trénadiel, 2016