Paleozoic (the time of the oldest life)

This era lasted about 340 million years. The situation is still not stable earth, the climate is changing and frequent rainfall is very large. However, in this age begin to have signs of life, such as: single-celled creatures (microorganisms), small animals that invertebrate, fish species, amfhibi and reptiles. There are also plant species of algae and grasses. Age is also called the era of primary (first time).