The Evolution of Life Through Ancient Eras
580 million years ago: Multicellular plants became quite common, and the first soft-bodied animals emerged. Today, fossils of soft-bodied animals dating back to this period have been discovered.
540 million years ago: Oxygen levels continued to rise in the atmosphere. In the upper layers, sunlight facilitated the formation of the ozone layer, which blocked ultraviolet radiation from penetrating the atmosphere. This was a crucial condition for life to begin colonizing the land, where the first continental landmasses had appeared.
505 million years ago: The next stage of biological development began during the Ordovician period, the second period of t...