News Finding: Origin of animals may **NOT** have been triggered by oxygen. 
Paper Finding: Although levels of atmospheric oxygen may have reached 10% PAL by 580 Ma, the geochemical record does not preclude oxygen levels of 0.5-4% PAL during the Cryogenian Period .
News Context: Origin of animals may **NOT** have been triggered by oxygen. 
Paper Context: Such an early evolution for sponges would be well before the general oxygenation of the deep oceans in the Ediacaran Period. Although levels of atmospheric oxygen may have reached 10% PAL by 580 Ma, the geochemical record does not preclude oxygen levels of 0.5-4% PAL during the Cryogenian Period . Indeed, oxygen levels this high may have been reached as early as the Great Oxidation Event some 2.3-2.4 billion years ago and may have persisted at these levels through much of the intervening time , with some likely swings to lower levels, however, around 1.8 billion years ago .