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.
Earthâs atmospheric oxygen levels were highest in the Carboniferous, rising to about 35%, compared to todayâs 21%. There were many factors during that period that contributed to this. One that I havenât seen mentioned in other answers is the evolution lignin.