Iverna GardensProterozoic Era
For billions of years, there was nothing on the land. The oceans were warm and shallow, but no one swam in them. They were silent and empty because nothing was alive in the world yet. Then, tiny micro-organisms began to grow in the sea; so tiny they could not be seen by the naked eye. These micro-organisms split into two separate types: cells that got their food from the sun, which were the first green plants, and cells that got their food by eating the green plants. The latter were the first animals. At this time, bacteria called blue-green algae developed on the earth. Over millions of years, these algae covered the oceans; the algae were able to photosynthesize, and produced oxygen as a result. Oxygen prepared Earth for life, cleaning the atmosphere and giving it an ozone layer to protect it from the harmful rays of the sun.
Some micro-organisms evolved into colonies, forming sponges and corals. Also, at this time, sea anemones, starfish, sea-worms and jellyfish, which were the first creatures with a simple nervous system, developed.