<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Regina Redman</dc:contributor>
  <dc:creator>Rusty Rodriguez</dc:creator>
  <dc:date>2005</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Fossil records suggest that bacteria developed the ability to photosynthesize &amp;asymp;3,500 million years ago (mya), initiating a very slow accumulation of atmospheric oxygen (&lt;/span&gt;&lt;span class="xref-bibr"&gt;1&lt;/span&gt;&lt;span&gt;). Recent geochemical models suggest that atmospheric oxygen did not accumulate to levels conducive for aerobic life until 500&amp;ndash;1,000 mya (&lt;/span&gt;&lt;span class="xref-bibr"&gt;2&lt;/span&gt;&lt;span&gt;,&amp;nbsp;&lt;/span&gt;&lt;span class="xref-bibr"&gt;3&lt;/span&gt;&lt;span&gt;). The oxygenation of Earth's atmosphere resulted in the emergence of aerobic organisms followed by a great diversification of biological species and the eventual evolution of humans.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1073/pnas.0500367102</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>National Academy of Sciences</dc:publisher>
  <dc:title>Balancing the generation and elimination of reactive oxygen species</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>