Higher Order Evolution Begins Adequate Amt Oxygen Desk Mat

Ever wondered how much oxygen in the atmosphere existed during the Cambrian explosion or around the Permian-Triassic extinction event? Wonder no longer and showcase your evolutionary sense of humour with this desk mat featuring the relative oxygen content of Earth's atmosphere during the course of the last billion years. Caption says it all: "Higher Order Evolution Begins With An Adequate Amount Of Oxygen". Make others do a double-take about how oxygen levels and evolution impacted each other with this educational, scientific saying desk mat!