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.
Carbon dioxide concentrations dropped from 7,000 parts per million during the Cambrian period about 500 million years ago to as low as 180 parts per million during the Quaternary glaciation of the last two million years.