Explore the fascinating oxygen fluctuations during the Paleozoic Era in this 25-minute video lecture. Delve into the timing, extent, geochemical evidence, and biological implications of these atmospheric and oceanic changes. Learn about carbon isotope excursions, redox-sensitive trace elements, and the role of land plant evolution in increasing oxygen levels. Discover how the Devonian oxidation event coincided with the development of the first forests and how sponges may have contributed to ocean oxygenation. Examine the potential Cambrian deoxygenation event and its effects on marine life. Gain insights into how oxygen levels influenced biodiversity, the 'age of fish,' and reef development throughout the Paleozoic. Conclude with a comprehensive summary of Earth's oxygenation history and enjoy some lighthearted bloopers at the end.