take longer than emergence of a new species but the apparent occurrence of high-level taxa without precedents is perhaps implying unusual evolutionary mechanisms. There is general consensus that many factors helped trigger the rise of new phyla, but there is no generally accepted consensus about the combination and the Cambrian explosion continues to be an area of controversy and research over why so rapid, why at the phylum level, why so many phyla then and none since, and even if the apparent fossil record is accurate. Some recent advances suggest that there is no clearly definable "Cambrian Explosion" event in the fossil record, but rather that there was a progression of transitional radiations starting with the Ediacaran period and continuing at a similar rate into the Cambrian. An example of opinions involving the commonly cited rise in oxygen Great Oxidation Event from biologist PZ Myers summarizes: "What it was was environmental changes, in particular the bioturbation revolution caused by the evolution of worms that released buried nutrients, and the steadily increasing oxygen content of the atmosphere that allowed those nutrients to fuel growth; ecological competition, or a kind of arms race, that gave a distinct selective advantage to novelties that allowed species to occupy new niches; and the evolution of developmental mechanisms that enabled multicellular organisms to generate new morphotypes readily." The increase in molecular oxygen (O2) also may have allowed the formation of the protective ozone layer (O3) that helps shield Earth from lethal UV radiation from the Sun. Creation of information A recent objection of creationists to evolution is that evolutionary mechanisms such as mutation cannot generate new information. Creationists such as William A. Dembski, Werner Gitt, and Lee Spetner have attempted to use information theory to dispute evolution. Dembski has argued that life demonstrates specified complexity, and proposed a law of conservation of information that extremely improbable "complex specified information" could be conveyed by natural means but never originated without an intelligent agent. Gitt asserted that information is an intrinsic characteristic of life and that an analysis demonstrates the mind and will of their Creator. These claims have been widely rejected by the scientific community, which asserts that new information is regularly generated in evolution whenever a novel mutation or gene duplication arises. Dramatic examples of entirely new and unique traits arising through mutation have been observed in recent years, such as the evolution of nylon-eating bacteria