In the Carbonifene of the Paleozoic era, animal gigantic diseases have spread. Huge flight insects occur in many places, but arthritis and other arthropods are also experiencing very big symptoms. Arthropods exist in the Paleozoic era and are the largest terrestrial arthropods in Earth history. Yasuda of 1 m in length is classified as arthritis. During the coal era, amphibians such as the land maze dragon amphibian also became huge. Large amphibians can grow to 2 meters in length.
According to the geochemical model, during the Paleozoic period near the Permian, the oxygen content in the global atmosphere has declined to about 15%, which is lower than the current atmospheric level of 21%. The Permits were one of the greatest extinctions of terrestrial and aquatic animals, including gigantic mites. However, oxygen reduction is not considered to play an important role in causing extinction. Some creatures that are particularly suited to living in an oxygen-rich environment, such as big flying insects and other huge arthropods, may not survive dramatically changing the oxygen atmosphere.
In the first two billion years of the history of the earth, the atmosphere will suffocate. And, strangely, the atmosphere starts to be filled with oxygen. At the moment, the group of atmospheric scientists insist that they know the reason. Evolution of bacteria changed the balance of gas in the atmosphere of the earth, resulting in the ultimate rise in methane loss and oxygen level. Oxygen content in the atmosphere will not rise from production of oxygen producing bacteria to at least 400 million years after. The theory of the Earth's oxygen source must take this gap into account. Until very recently, the major theorists believed that volcanic gases changed their composition during this period, eventually consuming less oxygen in atmospheric reactions. However, recent evidence from lock records hindered this idea.