The Staircase of Evolution


The more than 18,000 annual visitors who climb the stairs of Colle Aperto to reach the Botanical Garden, can start the tour right from the first step. Here is placed the first of the 10 visual tactile posters devoted to the evolution of plants, an exhibition characterized by an approach suitable for all visual and tactile, also blind and visually impaired, made with embossed designs and texts translated into Braille, as well as to a foreign audience, written in English. The theme of evolution is starting from the Big Bang Theory (bottom), and then to (above) the apex of the evolution of plants in correspondence with the first collections of the Botanical Garden already visible.

Since the formation of the solar system, 4.57 billion years ago, the path commemorates the appearance in the oceans of the first single-celled organisms, first those with no nucleus (bacteria), and then those nucleated, algae, from which until differentiated Marchantiophyta conquest the mainland, followed by the ancestors of the current club mosses and ferns, gymnosperms and angiosperms up to. The plants have a long story to tell, as they contributed significantly to make the Earth a living here too: they changed the unlivable primordial Earth’s atmosphere, they have changed the climate and led to the formation of soil.


The realization, supported by Lombardy Region and Fondazione Cariplo as part of the EST Project – “Educating to Science and Technology”, have collaborated with the branch of Bergamo Italian Union of the Blind and Visually Impaired, Stephen Schultka of the Natural History Museum in Berlin and Francesco Bracco, the University of Pavia. Below are the contents of the 10 stages of the route of the evolutionary plant scale.


  1. The ladder of evolution of plants. Essential tactile and visual representations of plant life on the planet. The plants have a long history as they have changed the Earth’s atmosphere, changed the climate and led to the formation of soil.
  2. 57 billion years ago: formed the Earth and other planets in the system solar.
  3. 8 billion years ago: in the oceans appear the first single-celled organisms lacking a nucleus, bacteria. After 300 million years there is an active oxygenic photosynthesis.
  4. 7 billion years ago: there are organisms with cells with a nucleus, the atmosphere continues to be enriched with oxygen. After 1.5 billion years there is the spreading of the multicellular algae.
  5. Ordovician Era, 490-443 million years ago: we are facing the colonization of land by the Marchantiophyta, bryophytes lack vascular tissues evolved from green algae and equipped with spores.
  6. Devonian Era, 418-354 million years ago: there are dense stands of riniofite and zosterofilli of 15-20 cm. They spread more and more tall plants with well-developed and differentiated vascular tissues. Appearance of the first plants with seed.
  7. Carboniferous Era, 354-290 million years ago: Immense proliferate humid forests with species bearing tree ferns, giant club mosses, large ferns and horsetails as big Calamites.
  8. Triassic and Jurassic Era, 252-142 million years ago: we are facing the strong diversification of gymnosperms, plants with seeds unprotected, dominant ovary in the humid tropical forests and adapted to the new arid climates.
  9. Cretaceous Era (142-99 million years ago): Conducting the proliferation of angiosperms, plants with protected seed.
  10. Tertiary Era, 65 to 5 million years ago: Presentation of most of the existing kinds. Today it is estimated about 422,000 living species of plants, a small part is in the Botanical Garden of Bergamo.