Although the Earth was formed some 4.500 million years ago, it had to wait another thousand million years before life emerged in the primeval soup of the Precambrian ocean.
Our world had taken the decisive step towards its differentiation in a lifeless solar system. Appropriate physical and chemical conditions allowed the appearance of matter capable of perpetuating itself: life had emerged in a humble but unstoppable way.
The complexity of living forms grew as environmental conditions changed. Body structures became more sophisticated giving rise to creatures that were more capable of exploiting the energy of the environment in order to metabolise it and convert it into living matter capable of reproducing its genetic endowment. The first bacteria and single-cell algae made way for the first invertebrates and from those soft functional creatures arose a new much more complex order with an internal skeleton: the vertebrates.
The appearance of fish marked the starting point for one of life’s greatest adventures. Oceans and seas had been conquered by plants and animals, but beyond, outside the protective water, stretched the world of the planet’s surface, a different world full of promise but also full of innumerable obstacles and limitations. And living creatures, after preparing themselves for it for three thousand million years, decided to go out and conquer it.