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.
the Cambrian. 45 Indeed, for 525 million years after the Cambrian explo-sion and for 3 billion years before it, the fossil record does not show any-thing like a steadily increasing number of new phyla. Nor does the sudden The Cambrian Explosion: Biologyâs Big Bang 351 # --)#B'5%)#  FIGURE 19A. Animal phyla and subphyla ï¬rst appearances: based on fossil dataalone (see appendix D) # --)#B'5%)# 8 FIGURE 19B.