The origin of life forms and their development in the course of the earth’s history into more complex organisms (biological evolution) is one of the most exciting natural science themes.

Approximately four billion years ago, the first forms of life began to evolve. The first bio molecules arose from inanimate matter. Early bacteria-like unicellular life forms without a nucleus had already started to emerge about 3.5 billion years ago. The first unicellular organisms with a nucleus appeared about 1.5 billion years ago. The development of the nucleus, which serves as the central command post for all higher developed cells, lasted around two billion years. It was an evolutionary tour de force that took about half of the entire time span during which life has existed on earth.

The first multi-cellular organisms probably appeared about one billion years ago. Five hundred million years later, most of the invertebrate phyla already existed. During this time centimetre-long worm-like precursors of vertebrates wriggled through the waters. Around 400 million years ago, vertebrate fish took over a leading role in the animal kingdom. At this time, life which for the previous 3.5 billion years had only existed in the water, also emerged onto the land. Small primitive land plants began to appear, amongst which millipedes, scorpions and primitive insects crawled and scampered. Some 30 million years later, tall tree-shaped plants were already growing and forming forests. Primitive amphibians, the first terrestrial vertebrates, which had developed from fish, made their appearance.

As the vertebrates continued to develop, the amphibians evolved into reptiles and then branched off to become mammals (about 220 million years ago) and birds (somewhat more than 150 million years ago). It was only in the Cenozoic era (beginning 65 million years ago) that mammals and birds were able to embark on the fantastic diversification of their species, when the extinction of the dinosaurs and other related species brought to an end the dominance of reptiles, which had lasted for more than 200 million years.