Logan is a name with Irish origins. The meaning of the name Logan is from the hollow. Common nicknames for Logan include Loag and Lo. Famous Loganâs include athletes Logan Bailly, Logan Coutre, Logan Kensing, and Logan Mankins.
During the Cambrian explosion, the atmospheric oxygen levels increased by up to 10 percent, and prior to that time the living creatures roaming the Earth were typically small, simple and often single-celled.
Today oxygen makes up about 20 percent of Earth's atmosphere, but for the first two billion years after Earth formed, its atmosphere was anoxic (oxygen-free). About 2.3 billion years ago, oxygen increased from a trace gas to perhaps one percent of Earth's atmosphere.Another jump took place about 600 million years ago, paving the way for multi-cellular life forms to expand during the Cambrian Explosion.ndeed, the jumps in atmospheric oxygen at 2.3 billion years ago and 600 million years ago do seem to be associated with Snowball Earth episodes (Fig. 14). However, scientists are still unsure exactly what the connection might be between the extreme ice ages and changes in the oxygen content of the atmosphere.