origin and evolution of species [1]
Since its formation some 4.6 billion years ago, the Earth has witnessed the genesis of continents and oceans and the appearance of animals and vegetation.
Ordovician 
Geological period marked by the appearance of the first vertebrates and new marine invertebrates. Corals, sponges and mollusks were especially abundant.
agnathan 
Jawless fish with a cartilaginous skeleton. Fish of this type still exist today (lamprey).
orthoceras 
Aquatic invertebrate fossil with a shell and arms equipped with suction cups; it was the ancestor of the nautilus, squid and octopus.
brachiopod 
Marine invertebrate fossil with a body protected by a bivalve shell.
Cambrian 
Geological period marked by the evolution of animals (appearance of mollusks, crustaceans) and the extinction of half of the marine invertebrates.
trilobite 
Marine invertebrate fossil with antennae and a carapace divided lengthwise into three lobes; it disappeared in the Permian period.
Precambrian 
The oldest and longest geological era, marked by the formation of continents and the appearance of ocean life.
cyanobacteria 
Blue-green algae, among the first living microscopic organisms to appear on Earth.
stromatolite 
Stratified calcareous concretion formed by microscopic algae (stromatolites), testifying to the existence of the first life-forms more than 3 billion years ago.